Cobalt DRIVE EFI - Moss Motors · this EFI kit. For 1970 and later, you will need to purchase and install Moss’s PCV kit part# 366-395 or come up with your own solution. This EFI

Part # 366-355 -1- Modified 11/18

Cobalt DRIVE EFIInstallation InstructionsMGB 1962-1974-1/2

PART # 366-355

Please read and understand these instructions before beginning installation.

If you feel uncomfortable with installation, an automotive repair shop or speed shop should be able to complete the install in about 8 hours. This is only an estimate and you will need to negotiate hours and pricing directly with your shop. An average do it yourself mechanic should be able to complete the installation in 2-to-4 days.

These instructions are broken up so that you will be installing either one part or several related parts in a section. When beginning each new section, it is extremely helpful to read through the entire section before beginning any work.

If you are unfamiliar with a term please refer to the glossary of terms near the end of these instructions.

Actual parts may vary from figures. It is our goal to make the instructions as accurate as possible however manufacturers change, parts change and sometimes we make mistakes. Please let us know if you find mistakes or have feedback on how these instructions can be improved.

READ THIS FIRST!The Cobalt DRIVE EFI dual throttle injection system is a combination of computer electronics, and hardware. While Moss Motors provides a base tune, which runs well on our own stock MGB, we cannot guarantee there will be no additional tuning required. The Moss Technical Services staff can help with mechanical hardware issues, but we cannot help with tuning to your specific application. To learn more about the Megasquirt tuning community, we suggest you visit http://www.msextra.com/forum-info

Before unpacking the system, please read and understand the full installation manual. If you are uncomfortable with the installation, or tuning process, stop. Either find a qualified installer to help, or return the kit.

Fuel injection systems run at substantially higher fuel pressure than your stock carburetors. It is therefore extremely important to follow all instructions in relation to setup of the fuel system. We strongly recommend a Class B fire extinguisher be present when first putting pressure to the system.

This kit includes an inertia cutoff safety switch that will disable the high pressure fuel pump in the event of an accident.

This kit is designed to bolt on to 1962-1974-1/2 MGB with dual SU carburetors. For fitment on later cars or other applications contact Moss Technical Support before purchasing this kit. Fabrication will be required for any vehicle other than '62-'74.5 MGB and will not be covered in these instructions.

Part # 366-355 -2- Modified 11/18 Part # 366-355 -3- Modified 11/18

Installation InstructionsInstallation Instructions

Required tools:

• MGB workshop manual

• Various flat and Phillips screw drivers

• Allen wrenches, 3/32", 5/32" , 1.5mm, 4mm

• SAE combination wrenches: 5/16", 3/8", 1/2", 9/16", 3/4", 1"

• 3/8" drive ratchet

• 3/8" SAE socket set

• Various 3/8" drive extensions

• 3/8" drive universal joint

• Right angle drill motor

• 17/64" drill bit (stepped bit recommended)

• Center punch

• Razor blade for cutting hose or a large hose cutter

• Jack and jack stands

• Measuring tape

• Felt tipped pen

• Metal cutting device (abrasive cut off wheel or band saw or hack saw)

• Masking tape

• Catch pan for gasoline

• Rags

• Silicone spray or petroleum lubricant

• Gasket scraper

• Isopropyl alcohol

• Throttle synchronizer

(Moss part number 375-324 suggested)

Optional helpful tools:

• 3/8" drive 1/2" swivel socket

• Masking tape

• An old or cheap 1/2" box or combination wrench you don’t mind modifying.

• 1" round gasket punch

Safety equipment:

• Class B fire extinguisher

• Safety glasses

• Gasoline fume rated respirator

• Gasoline resistant gloves (nitrile, not latex)

WARNING: Gasoline is extremely flammable. Work in a well ventilated area with a class

B fire extinguisher nearby. Make sure there are no open flames such as a water heater or clothes dryer pilot lights.

Instructions

1) On level ground, lift the rear of the car and support it with jack stands.

WARNING: Never work under a vehicle supported solely by a jack. Jack stands must be used to support the vehicle. It will help to have the front of the car on jack stands as well. If you have the stands for it, lift front of the car and support it with jack stands.

2) Remove the battery access panel. Disconnect the battery.

3) Collect the following items:

AB

C

D

E

Figure 3

BOM STEP 3

ID Qty Unit Part# Description

A 3 EA 770-021 GROMMET, 1-1/2 X 1-1/4"

B 1 EA 772-294 P-CLAMP, 2.00" ID

C 1 EA 324-590 WASHER, FLAT, 1/4"

D 1 EA 322-170 BOLT, HEX, 1/4 UNF X 1/2", FULL THREAD

E 1 EA 772-331 SCREW, #8-18, SELF DRILL&TAP

Requirements for your MGB:

Alternator, battery and overall electrical supply: Your MGB must be negative ground and have an alternator. The fuel injection system requires more amperage and voltage at idle speed than a generator can provide. We have tested several different alternators that look like generators and none of them output as steady as a regular alternator in an alternator frame. We recommend Moss part# 130-078 as it has been tested and confirmed to put out consistent voltage at idle with the extra load the fuel injection system puts on the electrical system.

Your MGB must be a single 12 volt battery placed in the right hand battery box. Dual 6 volt batteries will not work as a fuel sump will be placed in the left hand battery box.

Electronic fuel injection is far more sensitive to battery and charging system voltage than a carbureted car. The ECU, fuel injectors, idle air control motor and fuel pump are all negatively affected by low battery or charging system voltage. Make sure the battery is in good health. If you don’t have means to test it yourself, most auto parts store will test batteries free of charge. We recommend a battery maintainer be hooked to your car if it will sit for more than a few days.

A fully charged battery with a healthy charging system allows the car to start and run properly. Low system voltage can cause poor starting, idling and drivability, especially at low RPM.

Thermostat: The base tune (calibration) in this kit relies on the coolant temperature being over 160° for normal operating temperature. Coolant temperature less than 160° will result in a higher idle speeds and a richer air fuel ratio. We recommend a 180° thermostat be installed before installing this EFI kit.

Overall engine health: Your engine must be in good running order. Make sure you have even compression, valves are in adjustment, even vacuum at idle, no flat cam lobes, etc.

Ignition system: Your MGB must have suppressed ignition leads (spark plug wires) and resistor style spark plugs. EFI is sensitive to the electrical noise that solid core plug wires and non-resistor spark plugs make. Electronic ignition (such as Pertronix) is strongly recommended. We have tested points style ignition systems and found the electronic ignitions to be more consistent and provide a better signal to the ECU. Caution: No capacitive discharge ignition (CDI) systems can be used with this system. The ECU will be severely damaged. With the vacuum advance disconnected and plugged, set ignition timing to 10°-15° before top center. This is a good starting point

and where our car was set when developing the base tune.

There are no vacuum advance ports provided on the throttles. The base map was not designed around vacuum advance (either ported or manifold referenced). The vacuum advance on your distributer should be capped off prior to the installation of this kit. The distributor will still have it's mechanical advance which is ideal for this kit.

Fuel: Use the same fuel as you did carbureted. The ECU tune (calibration) was made using California 87 octane. Note, if you hear detonation or the spark plugs show any signs of detonation, up the fuel rating and or retard the ignition timing 2° at a time until all signs of detonation are gone.

Emission systems: This EFI kit was not designed around the air pump equipped on cars from 1970 to 1974. There are several reasons for this. First, this EFI is a "speed density" system. Meaning the ECU uses manifold pressure, throttle angle and engine rpm to calculate how much air is entering the engine and therefor how much fuel to deliver. The gulp valve can skew the MAP sensor readings, which means the wrong amount of fuel will be delivered. Second, if you ever plan on installing a wideband and enabling EGO (recommended), the air pump will skew the readings to the wideband. Again, the wrong amount of fuel would be delivered. Finally, we realize that most MGB’s, at this point in time, do not have the air pump system intact. We tuned a base map in the ECU that would run on the majority of cars.

The factory PCV system for 1962-1969 is compatible with this EFI kit. For 1970 and later, you will need to purchase and install Moss’s PCV kit part# 366-395 or come up with your own solution.

This EFI kit is compatible with the charcoal canister and its operation. The only change is the float bowls no longer exist and therefore the vacuum line to the canister will need to be plugged. The fuel tank pressure will be relived through anti-run on valve just as in the stock configuration. The anti-run on valve should be kept in place for this reason.



Fuel sump return line

You will be installing a 5/16" fuel hose that bleeds excess pressure from the fuel sump to a return sleeve in the fuel tank’s filler neck. Running the return before installing those other components makes their installation easier. The 5/16" hose is longer than it needs to be. The excess hose will be used to run another fuel line later in the instructions. When installing any of the fuel hoses, put masking tape over the ends to keep debris from entering the hose. This also gives you a place to label the hose with a felt tipped pen to keep organized.


A

B

Figure 5

BOM STEP 5


A 156 INCH 051-262 HOSE, FUEL, HP, 5/16"

B 1 EA 280-190 GROMMET, 1/2" ID, 7/8" HOLE

6) Starting from under the car, near the factory fuel pump, route the 5/16" fuel line through the right side battery box. It should pass through all three of the grommets and the p-clamp and into the empty battery box. Feed enough of the hose so that about 1ft of hose is hanging out of the bottom of the battery box. Eventually this end of the hose will be installed on the fuel sump but for now it should be left hanging under the battery box. Cover the end with masking tape and write "return" on it. Figure 5.

Figure 6

7) Next, the long end of the hose needs to be routed into the trunk where it will eventually feed back into the fuel tank. Use the provided cable ties to loosely hold the return line to the factory hard line that routes over the axle and back to the fuel tank. If your MGB has a fuel tank breather line, it will pass through the trunk floor near the right tail light. Next to the bulk head fitting for the vent line, you will find a small plug in the trunk floor. Knock the plug out and pass the fuel sump return line through the hole. If your car does not have the hole, you will need to drill a 7/8" hole near the fuel tank filler and route the fuel sump return hose through it. A stepped drill works great for this. Make sure you check the other side of the panel before drilling. Install a grommet (provided) in the hole before passing the fuel hose through. A bit of silicone spray on the grommet and hose will help with the hose pass through.

3A) Install a 2" p-clamp directly above the drive shaft and in between the 2 battery boxes. This clamp will be used to keep the fuel hoses from touching the drive shaft during full suspension compression. Some cars will have a 1/4" threaded hole in the chassis in this location make sure you look hard as it may be covered in road debris or undercoating. Use the provided 1/4-28x1/2" bolt and a 1/4" flat washer if your car has the threaded hole. Otherwise use a self-tapping screw. Drill into the extra boxed section at the corner of where the top and front of the battery boxes meet. This will ensure that the screw does not protrude into the passenger compartment (carpet) of the car. Figure 3.

Figure 3

4) There are 3 grommets provided in the kit that are sized for a 1 1/2" hole in sheet metal. Install a grommet in both upper, front holes of the right hand battery box (passenger side of LHD cars). Install the final grommet in the upper, front hole in the right hand side of the left battery box. Figure 4.

Figure 4



13) Read page 4 of the fuel sump instructions. This will tell you how to install the hose on the AN fittings. If a heat gun is not available, dipping the end of the hose in boiling water works great. The Figure 13.

Figure 13

14) Cut a 3 1/4" length of hose off the 19" section of 3/8" hose.

15) Install the short 3 1/4" hose on a 90° AN fitting. Install a hose clamp to secure the hose to the fitting.

16) Slip a hose clamp over the end of the 209" long 3/8" hose. Install the long 3/8" hose on a 90° fitting. Tighten the hose clamp to secure the hose to the 90° fitting.

17) Read the section on page 2 of the fuel sump instructions that refers to installing the fittings on the fuel sump lid.

18) Install the 90° fitting with the short 3 1/4" hose on the "IN" orifice on the fuel sump lid. The fuel filter will be attached in a later step. Figure 18.

Figure 18

209"

3½"

Do not over tighten the fittings. There are instructions on how to tighten the fittings in the sump instructions.

19) Install the 90° fitting with the 209" long section of 3/8" hose onto the "OUT" orifice on the fuel sump lid. Figure 18.

There are 2 fuel filters supplied with the fuel injection kit. One filter is a low pressure, pre-sump filter Wix part #33033 that can be identified by the seam around the center of the filter body. The high pressure post sump filter Wix part number #33482 has the seam at the end of the filter body. The high pressure filter found in the fuel sump kit will be installed later in the instructions.

WARNING: Do not use the low pressure filter on the high pressure side of the fuel sump. It will leak fuel causing a fire hazard.

20) Find the low pressure Wix filter #33033 that is supplied with the main fuel injection kit (not in the sump kit). In the Wix filter box you will find a filter, 2 short sections of hose and 4 spring type clamps that will not be used.

21) Install another hose clamp over the short section of hose which is on the 90° fitting. Install the low pressure filter in the short section of hose and adjust the second hose clamp so that it is clamping the hose to the filter. The filter has and arrow on it. Make sure the arrow is pointing toward the fuel sump (direction of fuel flow). This Wix filter is widely available and inexpensive. Mounted in in this location near the sump makes it easy to replace as it will be just under the battery access panel. Refer to Figure 18.

8)The fuel sump return line will be connected to the fuel filler tube later in the instructions. For now, cut the fuel sump return line about 6" past the fuel filler. This will leave plenty of extra hose. It will be trimmed to fit once the sleeve is installed. Figure 8.

Figure 8

Fuel sump The provided fuel sump kit has a high pressure fuel pump that is suitable for fuel injection. Do not remove the stock fuel pump from your MGB as it is required to feed low pressure fuel into the fuel sump.

There is 3/8" high pressure fuel hose that is supplied in the fuel sump kit. This hose will not be used. Instead use the provided 19 foot length of 3/8" hose provided in the main fuel injection kit.


A

B

Figure 9

BOM STEP 8


A 1 EA*NAS

FUEL SUMP

B 1 EA CONNECTOR, FUEL SUMP*NAS - NOT AVAILABLE SEPARATELY

10) The fuel sump will be installed in the left-hand (driver side U.S.) battery box. Remove the left rear wheel to help with installation.

11) Install the electrical connector provided in the sump kit onto the fuel sump lid. Make sure the Purple wire is on the (+) terminal and the Black wire is on the (-) terminal. Figure 11.

Figure 11


Figure 12

A

B

D

E

C

BOM STEP 12


A 1 Set INST- 772-958 INSTRUCTIONS

B 19 Inch 051-260 3/8" FUEL HOSE

C 2 EA *NAS 90° AN FITTING

D 1 EA 772-945, WIX# 33033

LOW PRESSURE FUEL FILTER

E 3 EA 772-960 3/8" HOSE CLAMP*NAS - NOT AVAILABLE SEPARATELY



25) Collect the following items from the fuel sump kit and the main kit: Figure 25.

AA

Fuel Sump Kit Main Kit

B

C

HG

F

E

D

Figure 25

BOM STEP 25


A 3 EA *NAS GROMMET

B 3 EA *NAS ALUNIMUM BUSHING

C 6 EA *NAS FLAT WASHER 5/16"

D 3 EA 772-962 PLASTIC SPACER

E 3 EA 770-577 NUT 1/4" UNF

F 3 EA 322-280 BOLT 1/4 UNF X 2 3/4"

G 1 EA 772-961 5/16" HOSE CLAMP

H NOT USED FOR COBALT DRIVE EFI*NAS - NOT AVAILABLE SEPARATELY

26) On the bottom of the fuel sump there are 2 hose nipples. The smaller metal nipple will not be used in this installation. Leave it exposed to the atmosphere (do not cap it off). The other is 5/16" plastic and molded into the sump, and is used to return excess fuel to the main fuel tank. Install a hose clamp on the fuel sump return hose which was routed to this location earlier in these instructions. Install the return hose (which was run into the battery box previously) on the 5/16" nipple and tighten the clamp.

27) Feed the outlet hose through the same grommets and p-clamp as the return hose, as you lower the sump into place. Use slicone spray on the hose and grommets to lessen the friction and keep the grommets in place. Install the fuel sump in the battery box using the hardware gathered and the holes drilled in the previous steps. Make sure to install the flat washers in between the fastener and the battery box. Fastener torque is to 7 lbs.-ft. Figure 27.

Figure 27

28) Working from underneath the vehicle, feed the long 3/8" fuel sump outlet hose alongside the return hose through the p-clamp and the battery box. For now, this fuel line can be left hanging under the car. It will be routed to the front of the car later in the instructions. Make sure that the outlet and return hoses make gradual curves and do not kink. Figure 28.

Figure 28

22) Find the full size template located on the last page of the fuel sump instructions. Measure the template to ensure the accuracy. If the template is not accurate, visit the manufacture’s web site and print another that is accurate. You may need to adjust your printer settings make it print correctly. Cut the template out but leave the three crosses indicating the mounting bolt centers. Punch through the crosses using a pen or pencil so their locations are evident from the non-printed side of the sheet. Figure 22.

Figure 22

22A) Fit the template in the battery box on the wall closest to the driver side fender. The printed side of the sheet will not be visible as it should face the left side of the car. Adjust the template so that all three mounting holes are located on the same plane of the battery box wall as pictured. Figure 22A.

Figure 22A

Alternatively, you can try fitting the template from the wheel well side. You will need to cut a large section out of the template where the bump in the battery box wall is. Failing to relief cut the template for the bump will result with inaccurate mounting hole placement. The printed side of the template should be visible on this side of the battery box. Figure 22B.

Figure 22B

23) Once the template has been placed, transfer the mounting hole locations onto the battery box wall using a center punch.

24) Use a small pilot drill to drill first and then open the holes to 17/16". Tip: stepped drills are short and are excellent for drilling sheet metal. Figure 24.

Figure 24



Fuel Filler/Return Sleeve to Tank The stock filler tube must be modified to accept the fuel return sleeve which gives the fuel sump a place to return excess fuel.


AB

C

E

D

Figure 34

BOM STEP 34


A 1 EA 282-920 HOSE, FILLER TO TANK, ANGLED

B 1 EA 772-961 CLAMP HOSE 5/16"

C 1 EA 282-620 HOSE FILLER (STRAIGHT)

D 1 EA 772-226 FUEL RETURN ADAPTER

E 1 EA 282-626 CLAMP HOSE 2-1/4"

35) Make a mark using a felt tipped pen at the 12 O'Clock position on the fuel filler tube. This will help to orient the tube (and gas cap) later when you reinstall the tube. Remove the original fuel filler tube and hose from the fuel tank. Cover the opening with a rag so nothing falls in.

36) Find the short 2 1/2" diameter straight hose. Measure, mark and cut the hose down to 2 3/4" using a razor blade or large hose cutter. Masking tape can help mark a straight line around the hose. Figure 36.

Figure 36

37) Install the cut hose onto the fuel tank inlet. Push the hose down as far as it will go. Install a hose clamp but do not make it tight. The hose still needs a little movement.

38) Slide a second hose clamp over the short hose attached to the gas tank. Install the fuel return sleeve into the hose with the long 5/16" tube pointed down into the fuel tank. Aim the 5/16" fuel return inlet nipple toward the fuel sump return line installed earlier. Snug the second hose clamp, but again leave it loose enough for adjustment. Once again cover the openings with a rag to keep debris from falling in. Figure 38.

Figure 38

39) Find the 2 1/2" diameter hose elbow. Cut 3/4" off the short side. Cut 1 1/2" off the long side. Figure 39.

Figure 39

Fuel Sump Inlet Hose

The fuel sump inlet line will route from the "OUT" fitting on the stock low pressure pump to the "IN" fitting/filter on the fuel sump and step in diameter from 5/16" to 3/8".


A B

CG

FED

Figure 29

BOM STEP 28


A *15-3/4" INCH 051-260 3/8" FUEL HOSE

B ** INCH 051-262 5/16" FUEL HOSE

C 2 EA 772-960 3/8" HOSE CLAMP

D 2 EA 772-961 5/16" HOSE CLAMP

E 1 EA 053-098 REDUCER 3/8 X 5/16

F 1 EA 378-125 BANJO UNION 5/16"

G 6 (2 EXTRA) EA 370-650 FIBER WASHER

* Remainder of 19" hose** Remainder of hose from Sump return

30) Starting from inside the right hand battery box, route the remainder of the 19" piece of 3/8" fuel hose (now 15-3/4" long) through the p-clamp and in to the left battery box where the fuel sump is. Slip a hose clamp on and install the hose onto the fuel filter. Tighten the clamp.

31) Cut the 15-3/4" long fuel sump "IN" hose to length so it ends about mid way through the right side battery box. Install the 3/8" end of the of the reducer into the hose leading to the "IN" fitting on the sump. Refer to Figure 33. You can see the hose clamps in the picture where the reducer has been installed. Install a hose clamp to secure the 3/8" hose to the reducer.

32) Remove the stock banjo and braided hose assembly from the outlet side of the stock low pressure fuel pump. You may need to remove the stock low pressure pump completely or remove both inlet and

outlet of the fitting in order to access the outlet fitting. Install the banjo fitting and the remaining 5/16" fuel hose (left over from "Fuel sump return" line) onto the outlet fitting of the stock low pressure pump. Re-install the low pressure pump and or inlet fitting onto the pump. Run the 5/16" hose into the right hand battery box. 6 new sealing washers are provided, 2 for each banjo fitting and 2 extra just in case. Figure 32.

Figure 32

33) Trim the 5/16" fuel hose to length so that is can be joined up to the 3/8" to 5/16" fitting going to the sump "IN". Slip a hose clamp over the 5/16" hose and insert the fitting into the hose. Tighten the clamp to secure the 5/16" hose to the reducer.

At this point you should have a fuel hose running from the outlet of the stock low pressure pump to the "IN" of the fuel sump. Check all hose connections. Make sure the stock low pressure pump is secured to the chassis and both banjo bolts are tight. Figure 33.

Figure 33



Fuel Sump Outlet Hose

The fuel sump outlet hose was previously installed on the sump "OUT" elbow and run through the right side battery box when the sump was installed. It will be run to a high pressure fuel filter and eventually make its way to the engine bay were it will feed the fuel rail. Make gradual bends in the hose so not to kink it.

47) The sump outlet line should be hanging near the factory fuel pump. Run it toward the front of the car, routing it over both cross members. Use the provided cable ties to secure the hose to the cars factory brake and fuel hard lines very loosely for now. Leave plenty of room for adjustment of the hose. Push the remainder of hose up into the RH side of the engine bay. Figure 47.

Figure 47

48) Use the provided 3/4" split loom to cover the hose where it goes over the cross members to protect the hose from abrasion on the sharp edges. Cut a few 1" lengths off the end of the 3/8" hose. Cut a slit down one side so they can be installed over the main 3/8" hose where the cable ties attach it to the hard lines. Figure 48.

Figure 48

49) From under the hood, route the fuel line along the stock hard line in front of the heater box and over to the left hand fender and then forward to the radiator support.

Eventually this hose will be connected to the fuel rail. For now leave the hose draped over the radiator support.

50) Find the high pressure fuel filter Wix #33482 (band around the end) and hose clamps that were included in the Edelbrock fuel sump kit. Find the P-clamp that fits around the filter and the self-tapping screw. This filter can be mounted anywhere in the fuel sump outlet hose. Pay attention to the arrow on the filter and make sure it points in the direction of fuel flow (toward the engine).

For 1962-1967 cars it will be easiest to mount the high pressure fuel filter under the hood as they don't have room in the transmission tunnel. See Figure 50a. Note in Figure 50a the IAC has been installed. 62-67 cars should wait until after the IAC is installed to mount the fuel filter.

1968 and on, cars have no trouble mounting the filter forward of the transmission cross-member in the tunnel. See figure 50b.

40) Install the short side trimmed down elbow onto the return sleeve. Figure 40.

Figure 40

41) Cut the stock fuel filler metal tube about 2 1/2" from the bead. Deburr the edge and clean the tube. Figure 41.

WARNING: Cutting metal produces sparks. Do not cut metal near the open fuel tank. Serious injury and explosion can occur.

Figure 41

42) Install the rubber seal on the cut filler tube. Test fit the cut tube into the cut elbow. Figure 42.

Figure 42

43) Test fit the 5/16" return line to the return sleeve. Clock the return sleeve in the direction you desire. Ideally the return sleeve will be clocked so that the return hose has the shortest run possible without kinking. Do not cut the 5/16" return hose at this time. Ideally the return hose should be inserted all the way to the base of the return sleeve. The 2 larger diameter hoses will be obstructing the 5/16" hose from touching the base of the sleeve. Use a felt tipped pen to mark on the large diameter hose or hoses around the 5/16" return hose.

44) You may need to trim either the short straight hose on the fuel tank inlet, the short side of the elbow, or both hoses. Trim only 1 part at a time and test fit the entire assembly after each cut. Make small radius relive cuts on the 2 larger diameter hoses around the 5/16" return hose instead of shortening the entire hose. The goal is to be able to install the 5/16" return hose fully and have both of the large diameter hoses as long as possible. Figure 44.

Figure 44

45) Once the 2 larger diameter hoses have been trimmed to fit the 5/16" return hose, permanently install the 2 hoses and return sleeve using the 4 provided hose clamps.

46) Finally, trim the 5/16" return hose. Install a hose clamp, install the hose to the sleeve and tighten the clamp. Figure 46.

Figure 46



Throttle bodies

Note: the TPS sensor, intake air elbows, throttle bell crank, fuel rails, fitting and plug (in fuel rails) have been installed on the throttles.

The throttle bell crank is set to a specific position that the Microsquirt is calibrated to. Do not move the throttle bell crank on the shaft as the calibration will be thrown off.


Figure 55

A A

BB

C

H

R

RI

Q

K

S

T

L

M N

OP

G

F

J

ED

If you choose to mount the filter under the hood, hold off on cutting the hose and mounting filter. There are other components under the hood that still need to be mounted before you choose a permanent location. However now is the time to secure the hose to the bottom of the car. Tighten up the cable ties holding the hose the car. Use the 1" cut sections of hose at the cable tie locations. Install additional cable ties where necessary to keep the hose out of harm’s way.

Figure 50a

Figure 50b

51) If you are mounting the filter under the car, permanently install the filter now. Route the fuel hose to the filter and tighten up the cable ties along the hose routing to the filter. Cut the hose, install hose clamps and secure the hose ends onto the filter. Secure the outlet side of the fuel filter’s hose as well up until the point where the hose heads up to the engine compartment.

Carburetors

When removing parts from the car it helps to take pictures with your phone or digital camera to reference later. Label the components as they come off the car using masking tape and a felt tipped pen. Use zip top sandwich bags for smaller components. Box everything up together to keep organized. You or someone else will thank you down the line for your organization.

52) Remove the carburetors from the engine using a service manual as a reference. Figure 52.

Figure 52

53) The carburetor spacers/insulators and heatshields will be used with the throttle bodies. You may reuse the gaskets on each side of the spacers if they are in good condition (6 new gaskets are included). Otherwise clean the surfaces in preparation for new gaskets. Install the heat shield, throttle spacers and new gaskets.

54) Cap the original fuel supply hose that fed the carburetors using a method of your choosing. You can simply stick a bolt in the end of the hose, or remove the entire hard line from the car completely or something in between. Figure 54.

Figure 54


A 2 EA 772-928 40MM T-BODY ADAPTER PLATE

B 2 EA 696-100 CARB TO MANIFOLD GASKET

C 1 EA 770-023 BOLT, 1/4 UNF X 1 1/4"

D 2 EA 770-812 1/4 UNF STANDARD NUT

E 1 EA 772-930 THROTTLE CABLE BRACKET

F 1 EA 372-062 GUIDE, THROTTLE CABLE

G 1 EA 772-957 SHAFT COUPLER 5/16"

H 1 EA *772-982 THROTTLE BODY, NO TPS

I 1 EA *772-983 THROTTLE BODY, W/TPS

J 1 EA 331-466 LOW FRICTION THROTTLE CABLE

K 1 EA 462-411 -6AN, 90 DEG, FUEL FITTING

BOM STEP 55


L 1 EA *053-489 FUEL RAIL KIT, TWIN SU FI

M 2 EA 772-949 35#/HR, EV14 FUEL INJECTOR

N 4 EA 191-915 5/16 UNF X 1-1/4" HEX BOLT

O 4 EA 051-587 5/16" LOCK WASHER

P 4 EA 052-339 5/16 UNF STANDARD NUT

Q 112

EAEAEA

772-984 772-985 772-869

BELLCRANK THROTTLECLAMP SCREW8-32 X 3/4"

R 2 EA 772-952 3/8" NPT, 1/2" NYLON BARB

S 1 EA * FUEL RAIL PLUG

T 1 EA 772-934 TPS SENSOR

*NOT AVAILABLE SEPARATELY



60) Set a 4 hole gasket onto each throttle as shown in Figure 60. The tabs should be over the Idle air ports or a vacuum leak may occur.

Figure 60

61) Set a throttle body adapter plate onto each throttle. Note the scalloped injector cutouts on the adapters and line them up with the scalloped cutouts on the throttle bodies. The injector should have an unrestricted area to spray in. Installing the adapter plate incorrectly will cause the fuel to puddle and the result will be inconsistent AFRs, especially at low RPM. See Figure 61.

Figure 61

62) Install a nut on the 1/4-28x1 1/4" bolt and run the nut all the way down to the head of the bolt. Install the bolt and nut assembly onto the throttle bracket as shown. Install the other 1/4" nut to secure the bolt to the bracket. Figure 62.

Figure 62

63) Install the throttle cable bracket onto the throttles as shown in figure 61 using 2x 5/16-20x1 1/4" bolts, 5/16" lock washers and 5/16" nuts. Do not fully tighten the hardware. Figure 63.

Figure 63

56) Clean both throttles and fuel rails thoroughly inside. Used compressed air if available to blow any debris out. Use lint-free towels in the fuel rails. Any leftover machining chips, debris or lint will end up inside the engine or fuel injectors if it is not removed in this step. Fuel injectors have extremely tiny holes that will clog up easily. Please take extra care during this step to ensure the parts are clean inside.

57) Before you removing the fuel rails (to install injectors) make note of each fuel rail and fitting. The plugged fuel rail goes on the TPS throttle. The -6 AN fitting goes on the the non-TPS throttle. Lube all 4 injector O-rings using a little silicone spray lubricant or petroleum jelly. Remove the fuel rails from the throttles using a 4mm Allen wrench. Install an injector in a throttle body as pictured. Either injector can go in either throttle. Next install a fuel rail over the end of the injector and permanently install the fuel rails. Note: The fuel rail is longer on one side of the injector hole. Orient the fuel rail so that the long side of the rail is on the long side of the throttle shaft. Repeat this process for the remaining throttle, fuel rail and injector. Tighten the Allen head cap screws to no more than 2 1/2 lbs.-ft. (30 in.-lbs.) Figure 57.

Figure 57

58) On the end of each fuel rail is a Phillips head screw securing a small fuel crossover tube locking plate. Remove the screw and lock plate from each fuel rail. Lube both O-rings on the fuel rail crossover tube. Install the tube into each fuel rail. Reinstall the locking plates and screws. Figure 58.

Figure 58

59) Install one part of the throttle shaft coupler on to each throttle shaft as shown in Figure 59. Do not tighten the set screws.

The center section of the coupler should key into each coupler on the throttle shafts. Install it now.

Figure 59



68) Remove the old throttle cable. Remove the two Phillips head screws securing the cable guide at the firewall and replace with the provided guide. Working from the engine compartment, route the ball end of the new throttle cable down through the new guide and install the ball at the pedal fork just as the stock cable was. Reinstall a cotter pin to keep the cable in the throttle pedal. Figure 68.

Figure 68

69) Unscrew the bottom adjustment nut on the throttle cable housing. Open the throttle by hand using the idle stop arm. Slip the cable in the throttle cable bracket, put the end of the housing in the bracket and reinstall the bottom nut to hold the housing in place. Install the cable end into the bell crank. Figure 69.

Figure 69

70) Next you must adjust the throttle cable. Adjust the nuts on the throttle cable housing until the throttle bell crank and the throttle pedal hit their stops at the same time. It is helpful to have someone in the car that can depress the throttle to wide open slowly while you watch the bell crank.

If the bell crank hits the stop first, stop the passenger from depressing the pedal any further to keep from stretching the cable or bending the bracket. Spin the nuts on the cable housing toward the housing. This will give the cable a little extra length.

If the pedal hits the stop on the floor before the bell crank, spin the nuts on the cable toward the bell crank. This will shorten the cable.

Once the cable is adjusted correctly, snug the nuts on the cable housing to lock it in place. Figure 70.

Figure 70

64) Install two more 5/16"-20x1 1/4" bolts, 5/16" lock washers and 5/16" nuts in the through the holes shown in Figure 64. Do not tighten the hardware.

Figure 64

65) Install the throttle body assembly onto the intake manifold using the original hardware. You may need to need to adjust how far apart the throttles are from one another in order to get them over the intake manifold studs. The throttle coupler may not want to stay together. Just take your time and adjust the coupler as necessary. See Figure 65 for how the final result should look. Use the original hardware on the 4 studs to keep the throttles on the manifold.

Figure 65

66) Now that the throttles are on the manifold, tighten the 8 fasteners which secure the throttles to the manifold and the adapter plates and throttle cable bracket to the throttles. Do not tighten the coupler set screws. A 1/2" swivel socket on a 6" extension will be handy to tighten some of these fasteners. Also modifying a 1/2" combination wrench on a grinder to shave it down will help on the rest of the fasteners.

Throttle cable, stop & adjustment

In the following steps the throttle cable and wide open throttle stop will be installed. The throttle pedal and cable will be adjusted. You may notice the throttle stop (¼-28x1 ¼" bolt) does not allow the throttle butterfly to open up all the way and instead stops the throttle at about 80% open. This is intentional. DO NOT REMOVE THE THROTTLE STOP TO ALLOW FOR MORE THROTTLE OPENING! There will be no performance gain! The ECU is calibrated for the throttle stop to be in place. Removing or adjusting the throttle stop for more throttle opening will result in low load/speed drivability issues and will require a retune of the ECU.

67) Install the 90 degree -6 AN fitting on the non TPS side throttle fuel rail only hand tight for now. You will need to remove it later to install the fuel hose. Figure 67.

Figure 67



75) Install the IAC with the mounting bracket to the underside fender bolt (3rd bolt from back of the hood). There is a nut retaining a hood release cable bracket that can be removed and the IAC bracket installed over the exposed stud. Install the 5/16" flat washer and re-install the nut. The electrical connector should face the rear of the car. Aim the side fitting with ¾" hose toward the throttle bodies.

Note: Some MGB’s have the hood prop on the L/H side. Clearance may be an issue when the hood is closed. Carefully close the hood to ensure that the hood prop does not contact the IAC. If necessary, loosen the P-clamp and rotate the IAC down for more clearance. Figure 75.

Figure 75

76) The 90 degree plastic elbows have been pre-installed installed in the sides of the throttles. You may noticed they can be turned by hand pretty easily. This is as intended. There is thread sealing tape on the the threads to seal vacuum. They only need to be finger tight and pointed down and toward the fuel rails a bit. They will certainly move a bit in the next step when you install the hoses. DO NOT ATTEMPT TO TIGHTEN THE ELBOWS. They have a tapered thread and they will break with excessive torque. IF need be, spin them in to achieve the correct orientation. See Figure 77.

77) Install the 1/2" hose on each elbow mounted to the side of the throttles, with the hoses pointed down and slightly toward the L/H side of the car. Figure 77.

Figure 77

78) You will need to cut the 1/2" hose roughly in half in order to install the Tee fitting in so that the 2 throttles and the IAC are all connected. The hoses will need to be trimmed to length. Use the natural curves in the hoses to you advantage (point them toward the tee fitting). The hoses are a tight fit so no hose clamps or cable ties are required. Figure 78.

Figure78

71) Lastly, you must adjust the up travel stop on the throttle pedal. This is a bolt in the engine compartment, just in front of the throttle cable guide, that is pointed down, toward the top of the throttle pedal in the interior of the car. Adjust this bolt so that it is very near touching the flat on the throttle pedal. The goal is for the pedal to have a little bit of free play before the throttles begin to open. If you make this adjustment too tight, it will open the throttles causing a high idle. If it is too loose, it will feel like there is excessive throttle pedal play. Hold the bolt as you tighten the lock nut down. Figure 71.

Figure 71

72) Now that the cable and pedal adjustments have been made, slide the throttle shaft coupler so that it connects both shafts and lock the set screws down. Figure 72.

Figure 72

IAC valve installation


Figure 73

A

B

C

F

M

E

I

J K L

HG

D

BOM STEP 73

ID Qty Unit Part No. Description

A 18 INCH 367-460 1/2" EMISSION HOSE

B 1 EA 053-452 FILTER, IAC VALVE

C 1 EA 053-464 IAC VALVE

D 10 INCH 772-953 3/4" HOSE

E 1 EA 772-951 TEE, 1/2" X 3/4" X 1/2"

F 1 EA 462-412 P-CLAMP 1-7/8"

G 1 EA 052-339 NUT 5/16 UNF

H 1 EA 051-587 WASHER, LOCK, 5/16"

I 1 EA 051-009 BRACKET

J 1 EA 770-812 NUT 1/4" UNF

K 1 EA 051-583 WASHER, LOCK, 1/4"

L 1 EA 770-303 WASHER, FLAT, 1/4"

M 1 EA 322-920 BOLT 1/4 X 3/4"

74) Install the ¾" hose on the side fitting of the IAC. Cut the sleeve lengthwise so it will fit around the IAC and fit the sleeve over the body of the IAC. Put the P-clamp over the sleeve and install the IAC mounting bracket to the P-clamp using the ¼" hardware. Install the small air filter over the end fitting on the IAC. Figure 74.

Figure 74



86) Install the coolant temperature (CLT) sensor in to the coolant temperature block. The coolant temperature sensor is a closed element sensor (the end is all brass).

NOTE: the intake air temperature (IAT) sensor is an open element sensor meaning there is an exposed wire in a plastic mesh tip. Do not install the open element IAT in the coolant block as it will be ruined.

The threads are tapered (NPT). Over tightening the sensor will cause damage. If you are unsure on how tight it should be, error on the side of too loose. You can always fix a slight coolant leak later by snugging the sensor up a bit. Figure 86.

Figure 86

87) Refill the cooling system.

88) Find the manifold absolute pressure (MAP) sensor and install it on the firewall near the left hand hood hinge. Use the provided Velcro. Make sure to clean the MAP and firewall with isopropyl alcohol before adhering the Velcro. Figure 88.

Figure 88

89) Run the ¼" vacuum line from manifold vacuum to the MAP sensor. Do not tee anything else into this line. It is best to use a port in the intake manifold that is in the cross over tube and not directly over one of the intake runners. Placing this vacuum line directly over the runners can cause erratic MAP readings and therefore erratic fueling. Figure 89.

Figure 89

Fuel hose to fuel rail

79) If you have a '62-'67 and have been holding off to install the fuel filter, do it now. Refer to Figure 50. Make sure the filter is pointed in the correct direction. Trim the 3/8" fuel hose from the fuel sump to length, slip on a hose clamp and install it on the inlet side of the fuel filter. Tighten the clamp. Figure 79.

Figure 79

80) Once the fuel hose has been cut to length, remove the 90° AN fitting from the fuel rail. Install the fitting in the hose.

81) Reinstall the fitting to the fuel rail permanently. Use the same torque procedure as instructed with the fuel sump fittings. Figure 81.

Figure 81

CLT & MAP sensor installation

In this section you will install the remaining sensors.


Figure 82

AB E

F

H

G

D

C

BOM STEP 82


A 18 INCH 052-211 1/4" VACUUM HOSE

B 1 EA 772-936 CLT SENSOR

C 2 EA 697-360 GASKET, HEATER TAP

D 1 EA 053-439 CLT BLOCK

E 2 EA 051-583 WASHER 1/4" LOCK

F 2 EA 052-286 BOLT 1/4-28 UNF X 1-1/2"

G 30 INCH 051-777 VELCRO

H 1 EA 772-940 MAP SENSOR, 1 BAR

83) Drain the coolant to a level below the heater control valve.

84) Remove the heater control valve from the engine block. Clean the gasket surfaces of the valve and engine block.

85) Install the coolant temperature block in between the heater valve and the engine block using the supplied gaskets and bolts. Make sure the threaded hole is pointed toward the rear of the car. See Figure 81.



94) Locate the large main wiring harness. Find the end with the large 32 pin connector. From the engine bay, pass the 32 pin connector into the passenger side interior compartment through the rectangular hole uncovered in the last step. Route the connector down to the ECU and plug it in. Figure 94.

Figure 94

95) Out in the engine bay; find the first split in the harness. Route the leg of the harness that has all the sensor and actuator connectors in between the heater box and engine, over to the driver’s side of the car.

If your car has a charcoal canister, the harness should lay in between the canister and the passenger compartment (for a cleaner look). Figure 95.

Figure 95

96) Look at the area of the harness which is near the heater control valve. You will find a small branch of the harness which has a connector and a ring terminal. This connector is the CLT sensor connector. Plug it into the CLT sensor located in the CLT block installed in between the heater control valve and the engine block. The ring terminal is the ECU’s ground and will eventually be installed under the upper right engine plate bolt, but for now leave it loose. Figure 96.

Figure 96

ECU installation

90) Clean the back of the Microsquirt using isopropyl alcohol.

91) Cut serval strips of Velcro and attach them to the back of the MicroSquirt. Avoid covering the pinout key so it can be referenced in the future. Figure 91.

Figure 91

92) The MicroSquirt should be mounted in the passenger’s side foot well, up against the firewall in the top left corner or on one of the side walls depending on the year of the vehicle. You may need to take the carpet down in this corner. Clean the area with isopropyl alcohol. Cut more strips of Velcro and attach them to the Velcro that has been attached to the MicroSquirt. Peal the backing from the Velcro and use the MicroSquirt to affix the Velcro to the fire wall, with the connector on the top side. This will keep the wiring harness out of the foot well as much as possible and make reinstallation of the carpet easier. Figure 92.

Figure 92

Main wiring harness installation

93) Find the rectangular plug in the firewall above the passenger’s side foot well and remove it. The harness needs to pass through this plug. If you have a 1" round gasket punch use it to make a hole close to an edge but in the flat section of the plug. Once the hole is cut, make a slit from the hole to the edge so that the harness can be easily installed.

Next, make a separate 3/8" hole in the plug. The 3/8" hole will be used later for another smaller harness to pass through. Do not reinstall the plug in the firewall at this time. Set it aside until a later step. Figure 93.

Figure 93



• The last connector is the intake air temperature sensor which has not been mounted yet. The IAT sensor will be mounted later. Figure 97F.

Figure 97F

Once you have test fit the harness to sensors and actuators in this step, and routed the harness to your satisfaction move onto the next step.

98) Remove the upper right engine plate bolt from the back of the engine. You want to make sure the bolt head, washer and the engine plate are clean in this area as this is the ground for the MicroSquirt. Use a small piece of sandpaper to remove a small area of paint under the bolt head. Use an abrasive pad to clean the bolt and washer. Don’t forget the threads of the bolt.

Once you are satisfied that you have provided a good ground path, slip the bolt through the ground terminal in the harness and reinstall the bolt permanently. Figure 98.

Figure 98

99) Just after the harness exits the firewall, you will find a large coil of bundled wires with no connector on the end. These are all the unused wires. We did not cut these wires off in case you ever wanted to use any of the other features in the future. Tuck them in the passenger side fender. Figure 99.

Figure 99

100) The last branch has a bunch of spade terminals. Run this branch toward the passenger side headlight. None of the spades will be connected at this point. Figure 100.

Figure 100

97) From here on out, follow the harness around the driver’s side of the car and plug the connectors in to the sensors. Think of this as a test fitting of the harness. You may find that after plugging the sensors, IAC motor and injectors in, that you could route it a little cleaner if you put the harness under a hard brake line instead of on top (or something along those lines). Now is the time to get it right. Figure 97A.

Figure 97A

• Find the connector for the MAP sensor which you mounted on the firewall, near the drivers hood hinge. The connector will be in a branch very near to the MAP sensor. Figure 97B.

Figure 97B

• After the MAP, the main part of the harness makes a 90° turn toward the throttles. However there is a 2-wire connector that should go straight across the front of the brake master cylinder and plug into the IAC motor. Figure 97C.

Figure 97C

• Back on the main branch just after the MAP, there is a 3-wire connector which should be plugged into the TPS. Figure 97D.

Figure 97D

• The next 2 connectors are for the injectors. Figure 97E.

Figure 97E



104) The thread on the IAT sensor is 3/8" NPT. If your filter housing is thick cast, drill the hole to 37/64" and tap the hole with a 3/8" NPT tap. If the filter housing is sheet metal, drill the hole to 11/16" using a stepped drill bit. Do not drill the hole larger than .700" or the IAT sensor will not fit well or keep the filter sealed.

Some suggestions for drilling a single piece air filter element:

• Use masking tape on the inside of the filter element to keep the chips from embedding in the filter media.

• Dip the drill end in axle grease to capture the chips as they are made.

• Grease end of a tube such as an empty paper towel roll and stick it into the filter. The grease will seal against the inner wall of the metal. Drilling into the tube will keep the chips contained in the tube. Figure 104.

Figure 104

105) Once the hole is drilled, thread in IAT sensor if tapped for NPT or insert the IAT sensor and thread the provided 3/8" NPT nut onto the sensor. Snug the sensor down using a 3/4" wrench. Connect the harness to the sensor. Figure 105.

Figure 105

Fuse box and relay harness mounting

The EFI components require power, ground, fuses and relays completely separate from the stock car’s harness. This is to keep any extra loads out of the old wiring. There are only 2 wires that rely on the stock wiring harness. The first is an extremely low current key on voltage source. The second is the main battery positive cable that connects to the starter. That cable will have no problem with the extra load the EFI places on it.


A

B

Figure 106

BOM STEP 106


A 1 EA 772-992 HARNESS, F/P, RELAY

B 1 EA 053-457 FUSE BOX

107) The fuse box and relays will be mounted in the engine bay near the front right corner. Find the leg of the main harness with the 6 female spades. Plug all wires except the purple wire into the fuse box on any of the terminals. The position of the wires on the terminal is not important. Figure 107.

Figure 107

101) Reinstall the rectangular firewall plug with the main fuel injection harness passing through it. Figure 101.

Figure 101

IAT/MAT sensor mounting

Now that the harness has been laid out in the engine bay, you can choose a location for the IAT sensor. You want to choose a spot the connector will reach i.e. the front air cleaner housing. The open element should be placed in the flow of intake air. Mounting the IAT to outside of the flow of air is not desirable as it will be inaccurate. However, if you choose to mount the IAT outside of the flow, make sure it is far away from and not in direct line of sight to the exhaust manifold. Make sure to test fit the filters and run the connector to the place you plan to mount the sensor before drilling any holes. Air filters are not provided in this kit, but any filters that fit 1 1/2" SU carburetors will fit the throttles (even the stock filters). We have provided 4 each of 5/16 UNC 4 1/2" long bolts (322-175) for stock filters if you choose to use them. Another great alternative is the Cobalt cold air intake kit although it does require deferent length bolts than are provided in that kit.

102) Test fit the front air filter. Find the unconnected IAT connector that is forward of the front injector connector in the wiring harness. Connect the IAT sensor to the connector. Find a location in the metal housing of your air filter that you can mount the IAT. Mark the location using a felt tipped pen. Figure 102.

Figure 102

103) Remove the filter from the throttle body in inspect the inside of the filter which you intend to install the IAT. Make sure there is room for the drill and that you will not be drilling into the paper or foam element. Also make sure there is a means of capturing the drill chips. Once you are satisfied the location will work, move onto the next step.

Multi piece air filters can be easier in this respect as they can be disassembled. Single piece filters require some creative thinking in order to capture the chips.



Final wiring connections- relay harness

112) At the end of the main harness near the fuse box, find the purple wire which was not connected to the fuse box in an earlier step. Find the short Black wire which is hanging under the forward relay. It is the only wire that is not bundled with the rest of the harness. Plug the Purple wire from the main harness into the short Black wire from the relay.

The Purple wire from the main harness is fuel pump relay control wire from the ECU. It provides a ground to switch the fuel pump relay on. Figure 112.

Figure 112

113) Find the leg of the relay harness which has the fuse holder in it. This holder contains the 25 amp main fuse. Follow this leg down a bit more and find the Black wire with ring terminal. This is the main relay ground wire. Remove one of the engine mount bolts on the chassis side. Clean under the bolt and remove the paint so the ring terminal will make good contact. Install the ring terminal and reinstall the engine mount bolt. If your car has a coil mounted to the engine mount, you can use one of the coil bracket bolts, or any other clean chassis ground. Figure 113.

Figure 113

114) Further down the relay harness on the main fuse leg, find the red wire with the ring terminal. Connect the Red wire to the stud on the starter that the battery positive cable is attached to. This Red wire is the main and only power wire for the entire EFI system. Earlier cars have the starter solenoid mounted to the fender. In this case mount this wire to the always hot side of the starter relay. Mounting this wire to the normally cold side of the relay will result in a no start condition. Figure 114.

Figure 114

115) Still further down on the relay harness on the main fuse leg, there is a very long length of loom which has a sealed style 2 wire connector on the end. Feed this connector back to the fuel sump along the high pressure fuel hose. The connector is too big to run through the grommets in the battery boxes that the fuel hoses are running through. However you may be able to get it in the p-clamp in between the battery boxes. If not, use a cable tie to secure the fuel sump pump lead to the p-clamp to keep it from rubbing the drive shaft. Plug the connector into the connector on the fuel sump. Use cable ties to secure the loom along the fuel line. Figure 115.

Figure 115

108) Find the short leg of the relay harness which has the small ring terminal and the Blue/white wire with the female spade terminal. Install the ring terminal on the lug of the fuse box and the female spade on the remaining open spade terminal. Figure 108.

Figure 108

109) Find the Blue/White wire with the spade in the relay harness. This wire must plug into a key on voltage source. Typically there is an open terminal on the stock vehicle’s fuse box. If you are not sure which is key on voltage, plug it onto the terminal that is furthest from the front of the car. Right now you are just finding a spot to mount the fuse box and relays so you want to make sure the wire will reach the farthest terminals. Figure 109.

Figure 109

110) Find an open spot to mount the fuse block and relays that does not stress any of the wires. The relays must be mounted in between the EFI fuse box and the vehicles stock fuse box. The thinner of the Blue/White wires will eventual need to be connected to a key on source from the stock fuse box. Once the position is chosen, permanently mount the fuse box and relays. You can use the Velcro or self-tapping screws to mount both components. Or you may even find an open threaded hole or 2 that can be used in conjunction with the Velcro. You can rearrange the wires which mount to the fuse box onto any terminal to make it look cleaner. Figure 110.

Figure 110

111) Disconnect the Blue/White relay harness wire from the stock fuse box. You will reconnect it later once the battery is reconnected. Figure 111.

Figure 111



Final wiring connections- main harness

120) Install the fuses in the fuse box next to the corresponding wire colors:

• 3 amp fuse – Red wire- ECU power

• 3 amp fuse – Gray/Red- OPTO IN(+) tach input

• 10 amp fuse – Blue/Red wire- Fuel pump

• 5 amp fuse – White wire- Injectors

• 5 amp fuse – Brown- IAC power

• 5 amp fuse – Yellow- Wideband power (unused unless wideband is installed)

It does not matter which location any of the wires are on the fuse block. It only matters that the correct fuse is installed next to the correct wire color. Note: the Yellow wire’s 5 amp fuse is only in use if you install a wideband AFR sensor. If a wide band is not installed it can be used as a spare 5 amp fuse.

• The fuse box has an LED for each fuse. If a fuse blows, the LED will glow indicating a blown fuse; however the fuse box must have power. i.e. if the main fuse or relay fails, the fuse box will not light up. Figure 120.

Figure 120

121) The last connections that must be made are the RPM signal wires to the ECU. Starting from the fuse box on the main harness, work your way back about 1 foot and find the Grey/Black wire & the Brown wires with the small ring terminals. The Grey/Black wire is labeled (opto-) and should be installed on the negative (-) side of the ignition coil (trigger side of coil if unlabeled). The Brown wire should be installed on the positive (+) side of the coil (key on power if unlabeled). Figure 121.

Figure 121

Key on checks

WARNING: Wear your safety glasses and fuel resistant gloves. Make sure there is no open flame or any other sources of ignition.

In this step you will be checking for fuel leaks. It would be helpful to have a friend operate the ignition switch while you look at the fuel hoses and connections. Immediately turn the key off if you smell gasoline or see a leak.

122) Remove the 10 amp fuel pump fuse from the fuse box. The high pressure fuel pump must not be run dry so disabling it will allow the cars stock low pressure pump to fill the high pressure fuel sump. Figure 122.

Figure 122

116) Near the end of the fuel pump leg, There is a black wire with a ring terminal, Run the Black wire with the ring terminal to the negative (-) battery terminal. This is the fuel pump ground wire. Although the battery is disconnected at this point in time you can still connect the fuel pump ground to the battery terminal. Later when you reinstall the battery terminal, the fuel pump ground will be tightened. Figure 116.

Figure 116

117) Back up in the engine compartment; find the long leg of the relay harness with the 2 Red non-terminated wires. Feed this leg in to the passenger compartment alongside the main fuel injection harness through the 3/8" hole that was cut in the firewall plug. Continue to run the leg through the dash to the driver’s side foot well. These 2 wires will connect to the inertia fuel cutoff switch. Figure 117.

Figure 117

Inertia fuel cutoff switch

The inertia switch is a safety device which will cut power to the high pressure fuel pump in an accident. It is easily reset by pushing the red button on top in case it accidently gets triggered.

118) Find the inertia switch. Read the instructions that come with it. Mount it in an area in the drivers foot well or under dash that a) the wires run in the last step reach and b) that the driver can easily reach in case it accidently gets triggered. Figure 118.

Figure 118

119) Install the connectors that came with the inertia switch on to the 2 red wires coming from the relay harness (the red wires are very long and can be trimmed to length.) Connect the inertia switch and relay harness together. Either terminal can be attached to either red wire. The inertia switch is a simple pass through and is not polarity sensitive. Figure 119.

Figure 119



129) The air filters should not be installed on the throttle bodies. Remove them if needed. You will be running the engine with the filters removed so make sure there is nothing that will fall into the throttle bodies. The IAT sensor should be plugged in. You can remove it from the filter, or leave it installed in the filter and set the filter beside the forward throttle.

Having the filters removed allows you to spot fuel leaks at the fuel rail and injectors. Also you must sync the throttles, which requires direct access to them.

130) Have a friend crank the engine while you watch for fuel leaks. The engine may take several key cycles before it begins to run. Do not crank the engine for more than 5 seconds at a time. Turn the key off for 30 seconds between the 5 seconds of cranking. If the engine does not start after 3 cycles or immediately dies, the throttles may need to be opened slightly to give a little more idle air.

Note: holding the throttles more than 50% open during cranking initializes a "Clear Flood Mode" in which the injectors will not spray in order to clear out a flooded engine.

During the first few cranking events, the fuel rail and injectors are being purged of air. It takes up to 10 cranking cycles (of 5 seconds) for the engine to run on its own. Don't be discouraged if it doesn't start right away. After the first startup the engine will fire much much faster as long as you have not opened up the high pressure side of the fuel system.

Once the engine is running, make sure to check the fuel sump return line in the trunk for leaks as well as the fuel rail and the rest of the high pressure system.

131) Once the engine is running and the fuel system is leak free, let the engine come up to operating temperature. You may need to adjust the idle stop screws evenly on both throttles so that the engine will idle on its own. Use a 5/16" wrench to back off the lock nut and a 5/32" Allen wrench to adjusted the stop. Figure 131.

Figure 131

With the engine at operating temperature and idling without human assistance, the throttles must be synced so that they flow the same amount of air. If you are familiar with syncing the stock SU carburetors, this is the same procedure.

132) Loosen the throttle shaft coupler so that each throttle can operate independent of each other.

123) Remove the battery positive (+) wire from your ignition coil. The vehicle will need to sit for several minutes with the key on. Removing the power wire from the coil will keep it from overheating, or burning up points or electronic ignition system. Figure 123.

Figure 123

124) Make sure the ignition key is in the off position or out of the ignition completely. Reconnect the battery. Make sure to include the fuel pump ground wire on the negative (-) battery terminal.

125) Turn the ignition to the ON position but do not try to start the car. Immediately check for leaks visually and using your sense of smell. Shut the key off if you smell or see any leaks.

While the key is on, you should hear the factory fuel pump come on (clicking). It will take a minute or two for the factory pump to fill the fuel sump. Keep the key on for at least 2 minutes, while looking for leaks at the fuel sump, fuel filter, factory fuel pump and in the trunk at the filler neck and fuel sump return line. Tighten any loose fittings and recheck for leaks.

126) Use a volt meter or test light to check for key on power at the factory fuse box. Verify that the terminal is only powered on when the key is in the "ON" position. Once you locate key on power, connect the Blue/White relay harness wire to the key on source. Figure 126.

Figure 126

127) Turn the ignition key off. Reinstall the fuel pump fuse.

128) Turn the key to the on position (but do not crank the engine). Check the fuel sump return line at the return sleeve in the trunk first. Cycle the key several times while you watch this area.

This time while cycling the key you may hear the stock low pressure pump clicking and a whine for the first few seconds after the key is switched on. This is the high pressure fuel pump priming the high pressure system. The high pressure pump will only remain running if the engine is running or cranking. If the key is switched on, but the engine is not cranked or started, they pump will only turn on for a few seconds. Check for leaks and cycle the key several times. This time look for leaks in the high pressure side of the system along the hose and any connections you’ve made. Fix any leaks you find.

129) Turn the ignition key off and reconnect the coil wire you removed earlier.

Starting the engine and synchronizing the throttles

Again it will be helpful to have a friend to start the car (and shut it off) while you watch for fuel leaks. Once the car begins to run, there is 60psi of fuel pressure in the high pressure side. Leaks may appear that were not caught in previous checks.

Battery voltage is critical for the EFI system. Check to make sure the battery is completely charged before starting the engine. If it needs charging, do it first. A car battery with a voltage reading of 12.4V is only 75%. Make sure your battery is at least 12.6V before you begin.

It is best to have a battery charger, jumper box, or jumper cables hooked to another running vehicle for initial startup. You will need to crank the engine for several second repeatedly to bleed the fuel rail and injectors. Small lithium ion battery jumpers and (low current) battery maintainers are not up to this task.

While idling the engine and synchronizing the throttles, monitor the charging system voltage. Keep the battery voltage over 12.6V. This can be accomplished by a battery charger or revving the engine for 30 seconds now and then. Under 12.6V the ECU will try to raise the idle speed which will make synchronizing the throttles difficult.



Install TunerStudio and connect to your MicroSquirt

If your laptop does not have a serial port on it, you will need to order a USB to serial adapter before you can go any further. We strongly recommend purchasing the adapter from tunerstudio.com

These adapters are not created equal and many will have problems with the noise from the cars ignition system. Also driver support for other adapters may be problematic or not work at all for newer operating systems such as Windows 10. If you run into trouble connecting Tunerstudio to the MicroSquirt and you have a different USB to serial adapter. You will need to buy the adapter from efianalytics.com

Make sure you download in install the driver for the cable onto your laptop. The driver can be downloaded here: efianalytics.com

Installing TS

1) Go to efianalytics.com

2) On the left hand side under "Support", click "Downloads.

3) There is a free version of TunerStudio and several other versions with more features. Download and install TunerStudio on your laptop.

Connecting to TS to MicroSquirt

1) Disable the ignition coil under the hood of the car. The key will remain on for several minutes without the engine running and you don’t want the coil burning up.

2) There is a black cable which came with this EFI kit. It has a 2.5mm male on one end and a serial connector on the other. Connect the cable 2.5mm jack to on the cable to the socket on the EFI harness near the 35 pin connector.

3) If your laptop is older, it may have a serial port. If so connect the other end of the black cable to the serial port. If your laptop does not have a serial connection, you must use a USB to serial adapter. Plug the Black cable into the serial adapter and then into a USB port on the laptop.

4) Open TunerStudio on the laptop.

5) Click "Create new project".

6) Give your project a name. This is what your MicroSquirt will be called in TS. Something like "1970 MGB".

7) Turn the ignition key on. You want to hear the fuel pump turn on for a second or two to ensure the key is on.

8) Click "Detect". TS will begin searching the USB ports for a MegaSquirt. Once it finds something, click "Accept".

Troubleshooting:

If TS cannot find a device, try moving the cable to a new USB port and trying again.

If TS still will not detect, you may need to download a driver for your USB to serial. Go to the manufacturer of the adapter’s website, download and install the appropriate or latest driver. If you are still having trouble after the new driver has been installed. You may need to email the company which you purchased the USB to serial adapter from or the manufacture of the adapter. The other reason we recommend the adapter (from efianalytics.com) is we know it works.

9) Once you have clicked "Accept" in the last step, the main dash board will come up. This lets you know you are in. Turn the ignition key off and reconnect the ignition coil under the hood. Start the car. TS will go off line when the key is off, but should connect again once the car is running. The gauges are live now and will show you what the MicroSquirt is seeing.

Installing a wideband O2 sensor

We recommend AEM X Series Wideband Moss part number 907-270. This is the wideband used to develop the EFI kit. The next steps assume you are using the AEM wideband but other brands can be used as well.

1) Read the instructions that came with the wideband you purchased.

2) Mount the O2 sensor bung in your exhaust:

This requires drilling a hole and welding the bung (provided in the wideband kit) to your exhaust. Most exhaust shops offer this service for minimal cost.

• The sensor must be in the main exhaust, not an individual header runner. This is so that the sensor is reading all of the exhaust instead of an individual cylinder(s).

• The sensor must be must be at least 10* above horizontal to keep water in the exhaust from pooling in it and causing damage.

133) Hold the synchronizer tool sealed over the bore of either throttle. All of the air entering that throttle must pass through the synchronizer tool, or the reading will be inaccurate. Take note of the reading on the synchronizer tool.

Next, check the other throttle with the synchronizer tool.

Adjust the throttle stops so both throttles are flowing the same amount of air. On the cars we've tested, using Moss part #375-324, both throttles were set to flow 5.5 kg/hr at 950 RPM verified with an external tachometer (NOT THE TACH ON THE DASH).

Make sure to allow 5-10 seconds in between adjustments to let the engine and idle air control motor to settle. Figure 133.

Figure 133

134) Once both throttle flow the same amount of air, tighten the throttle shaft coupler so that the throttles are once again tied together. Open the throttles slightly by had a few times (rev the engine a bit) and let the engine settle. Double check that both throttles are flowing equal air. Readjust if necessary.

Warning: Ensure that the locknut on the throttle stops are securely tightened after adjustment. Normal vibration of the engine will cause the throttle stops to go out of adjustment if not properly tightened down.

The ECU will control idle air control motor, however the throttles must not be fully closed at idle. They must remain slightly open. If the throttles are closed too far, the engine will idle too low, not at all, or roughly. If the throttles are open too far, the engine will have a high idle speed. If the engine wants to die after you rev it up and let it drop back down to idle, open the throttles via the throttle stops a bit more until it comes down to idle smoothly.

The engine speed targeted by the ECU and IAC is 950 rpm with the engine coolant temperature above

160°. At lower engine temperatures, it will raise the targeted idle speed. Some may consider this idle to be a bit high; however it is necessary due to the extra electrical loads of the EFI system. We found that idling the engine lower than 900 rpm allows battery voltage to steadily decrease over time. This will cause idle and drivability issues.

Do not rely solely on the tachometer in your MGB to judge the idle speed. They can be inaccurate. The only real way to know if the engine is at targeted engine speed is to monitor it in TunerStudio. If your engine idles properly and the throttles are sync’d, no further action is required (regardless of what the tach on the dash displays).

The ECU will raise the idle speed over 950 rpm if the coolant temperature is below 160° or if battery voltage drops below 12.6V. It is critical to make sure the engine is above 160° coolant temperature and above is above 12.6V.

If the idle raises when you close the hood, the throttle cable is slightly too tight. Loosen the throttle cable nuts securing the cable to the throttle bracket. Give the cable a little more slack and close the hood again. When you can close the hood and the idle remains steady, the adjustment is good. Don't forget to re tighten the throttle cable nuts.

Final checks and test drive

135) Give the entire EFI system a visual once over. Check all the fuel hoses for leaks. Make sure all of the fuel hoses, wires and harness are secured to the chassis and protected from sharp or moving components. Make sure the fuel hoses don’t have any kinks.

136) Install the air filters and IAT permanently. We have provided 4.5" long 5/16"-18 bolts for stock air filters. Some cars have 5/16"-24 bolts from the factory but the throttles are tapped for 5/16"-18.

137) Install the battery access panel.

138) Install the wheels, torque the lug nuts and lower the car onto the ground.

139) Go for a short test drive and inspect for any fuel leaks or chafing of wires or fuel hoses. Let the engine cool down. Check the coolant level and top off as necessary.

140) Enjoy your Cobalt DRIVE EFI!



12) Select the AEM sensor has "X-Series" in the title. Note if you are not using the recommended AEM X-Series wideband, you will need to select a different option. If your wideband is not listed you can Select "Custom Linear WB" and plug your own numbers in.

13) Once you have selected your wideband, you need to write it to the MicroSquirt (Write to Controller). A message will appear stating a key cycle is needed for the changes to take effect.

14) Turn the key off.

15) Plug the coil back in so the car will start.

16) Start the car.

17) Once the car is running it may take a few moments for Tunerstudio to reconnect. If it won’t reconnect, try restarting TunerStudio and check the cable.

18) Once TS is connected, right click on any of the gauges (best to choose a gauge you don’t use or need much).

19) Hover the cursor over "AFR/EGO inputs+calcs".

20) Select "EGO Correction 1 – egoCorrGauge1". This will replace whatever gauge was there with the EGO correction gauge. This gauge will show you how much fuel is being added or taken away from the base map.

Notes on EGO correction:

• EGO Control is not active for the first 30 seconds after starting the engine. This is allow time for the wideband to warm up.

• EGO is not active below 145° coolant temperature.

• EGO is not active above 70% throttle or 90kpa (high load).

• EGO is not active below 20kpa (high vacuum deceleration).

• If the EGO gauge reads 90, it means the MicroSquirt is only giving 90% of the fuel that the base map is asking for. In other words, it is pull 10% of fuel. If the EGO gauge reads 110 it is adding 10%.

• We allow the EGO correction to add or take away up to 25% of the base map’s fuel.

• The EGO Correction gauge will nearly always be moving around when EGO control is active. This is completely normal.

• It is normal for EGO Control to add or subtract up to 10% (gauge reading of 90-110). No changes are required.

• If EGO Control is consistently adding or subtracting 10-15% (gauge reading of 85-90 or 110-115), there could either be a problem or the car may need the VE table tuned.

• If EGO Control is consistently adding or subtracting more than 15% there is most certainly a problem or retuning is strongly recommended.

• EGO will not always add or subtract the same amount. It will vary with load and rpm.

• The EGO Correction is fully configurable under "Fuel Settings" in "EGO Control". You can look here to see how EGO control is set up. We recommend leaving the settings as is.

• The MicroSquirt uses a base map to control the fueling of the engine. The main base map is called the Fuel VE table (Volumetric Efficiency). This table is found in the "Fuel Settings" tab. Without EGO control enabled, the MicroSquirt can only use the base map.

• The EGO control uses the wideband sensor so see how much oxygen is present in the exhaust. If there is too much O2, EGO control adds fuel. If there is not enough O2, it takes fuel away. EGO Control is using another table called "AFR Table" to target a specific air fuel ratio.

Ex: If the wideband reads 13.5 and the engine is running in a cell (in the AFR table) that is 13.0, EGO will add fuel in attempt to get the air fuel ratio to the targeted 13.0.

• The more that EGO has to add or take away means further from the base VE table. This is not ideal as EGO can only react so fast. The further from the base VE table means the longer it will take for the target AFR to be achieved. If it’s too far off it can even cause disability issues.

• If the EGO is consistently adding or taking away large amounts of fuel (+/- 15%) there could be a problem such as an exhaust leak tricking the wideband O2 sensor into seeing more air than actually went through the engine. EGO can be used as useful tool. If you are used to seeing EGO within a certain range and one day you notice its way off, you may have spotted a problem. I.e. a bad tank of fuel, exhaust leak, clogged air filter, plugged exhaust, etc. Anything that can affect how your engine runs will show up in EGO control being further off than usual.

3) Mount the gauge in the location of you choosing:

You will need to be creative here. You can mount it in your center console, or in your glove box or, make a bracket or purchase a gauge pod, etc.

If you do not want to make the gauge a prominent feature of your cockpit, you can simply cable-tie it to the harness somewhere under the dash. The gauge needs to be plugged in to supply a signal to the MicroSquirt. The gauge itself is a controller which turns the signal from the sensor into a signal the MicroSquirt can process.

4) Connect the wires from the wideband guage to the EFI harness:

Find the branch of the EFI wiring harness located 14" from the 35 pin MicroSquirt connector. There are four wires with female spade connectors.

• Yellow-Key on power wire. This wire comes from the EFI fuse box you installed under the hood (5 amp fuse) and is provided for you wideband’s power wire. Connect the Red wire from the AEM to this Yellow wire from the EFI harness

• Pink-MicroSquirt’s oxygen sensor signal wire. Connect the White wire from the AEM to this pink wire from the EFI harness.

• White/Black-Sensor ground wire. Connect the Brown wire from the AEM to this White/Black wire from the

• Black- Ground. This wire comes from the eyelet bolted to rear of the cylinder head. Connect the Black wire from the AEM to this Black wire from the EFI harness.

Only the 4 wires described above are used from the AEM wideband. The Green/Black, White/black and Blue wires are not used and should be individually sealed (taped) off.

5) Install the wideband sensor in the O2 bung.

The AEM does not require and special first time start up procedure or calibration. If you are using a different manufactures wideband you may need to free air calibrate before installing the sensor.

That completes the installation of the wideband hardware. You could drive the car as is and the gauge would display what the AFR. However the MicroSquirt will not recognize that sensor until you tell it to. In the next section labeled "Turning on EGO Control" you will set the MicroSquirt up to use the wideband to make fuel corrections live as the engine runs.

Turning on EGO Control

Before you can enable EGO control, you must first perform the steps in the section labeled "Install TunerStudio and connect to your MicroSquirt". Once you have successfully connected Tunerstudio to your MicroSquirt, move on to the following steps.

You must have a Wideband sensor installed, working and connected as specified in the "Installing a wideband O2 sensor" section. Enabling EGO control without a properly installed wideband will results in the engine running poorly and may cause engine damage.

1) Disable the ignition coil under the hood of the car. The key will remain on for several minutes without the engine running and you don’t want the coil burning up.

2) Connect the cable from the EFI harness to the laptop.

3) Turn the key on.

4) Power on your laptop and open TunerStudio.

When you first open TS click "Open Last Project" which will bring up the dashboard. At this time you should be connected. If there is a message stating "Off Line" you must find out why and correct it. Check the cable is plugged into the same port you used in the "Connecting to TS to MicroSquirt" section. Make sure the ignition is on.

5) Click on the "Fuel Settings" tab found above the gauges.

6) Click "EGO Control".

7) Next to "EGO Sensor Type" there is a dropdown menu. Select "Single Wide Band".

8) Close out of the "EGO Control" menu. Ignore the power cycle message for now. You will make more changes before you cycle the power.

9) Click on the "Tools" dropdown menu near the top of the screen.

10) Select "Calibrate AFR Table".

11) Click the box next to "EGO Sensor" and various sensors will be shown.



Often times it can be hard to feel right away if it made a positive or negative change right away. Make sure the change you made was positive before moving on. If you make too many changes too quickly it can be hard to tell what change was good and what was bad.

9) Do not expect someone else’s tune to work on your car perfectly. If you want to load someone else’s .msq into your MicroSquirt and try it that is fine. However don’t expect it to run as good as it did on their car. Each car will run a little different because they are different.

• If there is no problem present, it might just mean that your engine is different than the engine we tuned the base map on. Or maybe the fuel is different, etc. In the case that there is no problem but something is just different; you would want to make changes to the VE table so that EGO doesn’t have to work so hard.

• Remember to save your tune first and call it "Moss Base Map today’s date" so that you can always get back to it easily. Putting bigger numbers in the VE table will add fuel. Smaller numbers take fuel away. You will never get the car to 100% EGO all the time. It simply cannot happen. Even if you get really close, the next tank of fuel or certainly a tank of fuel in the next season will definitely change the readings. This is why EGO Control exists… To correct all the little inconsistencies in road conditions, fuel, air quality, etc. The point is, do not waste time trying for perfection when it is unobtainable. Get it within 10% and it is good. Within 5% and that is as good as it gets.

• You may find it better to make a VE table for winter and another for summer to compensate for the differences in seasonal fuel.

• If the engine feels good to drive, and the AFR is safe, nothing needs to be done. Don’t chase numbers for the sake of the number. The goal is drivability not a number on the EGO gauge.Tuning the ECU:

The ECU in this kit is supplied with at base map that will start and run the majority of MGB’s out there with a near stock engine. If your engine has a stock compression ratio, valve size, displacement, cam, etc. The base map will be great for you and nothing "needs" to be done.

That being said, each individual engine will most likely benefit from a custom ECU tune. If your engine specs are close to the specs of our rebuilt stock style engine, you may see less benefit. If you have a fast road cam and 1 point higher compression, you will benefit more.

Moss cannot help you tune your vehicle. Our sales and technical staff is not trained in tuning EFI. However we chose MicroSquirt/MegaSquirt because of the vast online community and the support they offer. There are many speed shops around the country and world that tune MegaSquirt on a regular basis. The manual for MicroSquirt can be found here: msextra.com/manuals/ms2manuals/

We encourage you to also visit: msextra.com/forums/viewforum.php?f=122 and its sub forums once you start tuning. Post on your favorite MGB

forum asking if others have tuned a MegaSquirt or Microsquirt.

We have one recommendation even for those who do not intend to tune your MGB: Purchase a wideband and install it as covered in these instructions. See the "Wideband oxygen sensor" section near the end of these instructions for more information.

Plan to tune yourself or prefer to have closed-loop feedback control fueling?

We recommend both TunerStudio and MegaLogViewer if you plan on doing any tuning yourself. In addition to these two programs, you must also purchase and install a wideband O2 sensor. If you plan on a dyno tune, speak with your dyno operator as they may already have these programs. In addition to these programs you must have purchase wideband oxygen sensor.

Hints to help you tune:

1) Save the base map first. This way you can always go back to the original setting if you need to.

2) Read through the MegaSquirt manuals. This will tell you how the different features work and how they should affect your car. Also read what others have done. Type the feature you want to tune into your favorite search engine and read how others have tuned that feature.

3) Use "save as" instead of "save. This will bring up a screen which asks you to name the new .msq. It defaults to the time and date. This is good, but you should also type in a description of the change you made. This really helps you keep track of what works and what doesn’t.

4) If you only use the "save" instead "save as", the program names your file "current tune" or will save the new tune over your old tune file name. It is very easy to lose track using "save".

5) Never tune with battery voltage below 12.6V.

6) Do not let VEAL tune idle or low RPM. We’ve found inconsistent results letting VEAL tune anything under 1500 RPM.

7) Do not chase unrealistic AFR. Just because you want the engine to run a certain AFR, it doesn’t mean you can make it. If the engine surges or knocks or makes black smoke the AFR is wrong. These are not modern engines and they do not run modern AFR’s.

8) Make small changes, one at a time and be patient. Drive on the small change for at least 5 minutes.

A few notes about the base tune:

Our goals for the base tune were to start and run the majority of MGB’s that are street driven and we focused on drivability. We were not out to make the most power or best fuel economy. If you hook up a wideband and want to know the target AFR’s here is a brief explanation. If you wish to look at exact numbers for any given load and RPM, you will need Tunerstudio on a laptop, and look at the tune file (.msq).

Idle: The target ARF for idle is 13.2: 1. We found we could idle at 14:1 but idle was more rough and the transition off idle would be flat for a split second. Richer and the off idle transition would get a little better but began to smell out of the exhaust.

Moderate acceleration: We target about 12.5:1

Hard acceleration: 11.5:1

Light cruise: from 2500-4300 RPM and loads below 70% we target 13.6:1. Think 50-70 MPH cruising down the highway. We found the car would run significantly leaner in this zone without issue, but we wanted to be conservative on the side of a little rich.

High RPM: From 4300-4900 RPM we transition from 13.6 to 12.5:1. From 4900 on we target 12:1 accept at full throttle or off throttle (deceleration).

Deceleration fuel cut: If the engine is over 2300 RPM, the throttle position is less than 1% and engine vacuum is significantly higher than idle, the ECU will shut the injectors off completely. The wideband will display its highest number when this is happening EX: 22.9:1. This is perfectly normal and will not damage the engine.

Also note: you may feel the fuel return sometime below 2300 RPM but above idle. This will correspond with the wideband reading something closer to 13.

Final notes: Do not worry if your AFR gauge is displaying numbers that are not exactly what is described above. Expect the AFR to always be moving, this is normal. You may see significantly higher or lower AFR’s during rapid throttle movements.

MicroSquirt extra features:

The MicroSquirt used in this kit is very powerful ECU that has may other features that this EFI kit does not take advantage of. Visit diyautotune.com/product/microsquirt-engine-management-system-w-8-39-wiring-harness/ for a full description of MicroSquirt. We do not have any plans at the writing of these instructions to add any of these features to our kit, nor can we tell you how to wire them or tune them. However, we didn’t want to take the features away from those who wants to go all out. All of the extra input and output wires in the harness have been coiled up off the main wiring harness. This coiled up leg of the harness can be hidden away in the fender well very neatly. Or, if you prefer, you can remove the loom from this section of harness and cut all the extra wires off. If you choose to cut the extra wires from the loom make certain you will never want to use any of those features. Also Moss Motors will not accept returned parts that have been modified.



Wideband oxygen sensor:

An oxygen sensor capable of reading AFR ranging from about 9:1 to 19:1.

This kit is not a "feedback" system out of the box. Meaning the fueling is all done using base maps and does not use an oxygen sensor as an input. Adding a wideband sensor is not required but is recommended for optimal performance, drivability and fuel mileage.

If the car runs fine without it why would we recommend that you add it? The MicroSquirt has the ability to use a wideband to make live corrections based on the oxygen content in the exhaust. No base map will be perfect for all road conditions, altitudes, ambient air conditions, etc. Also every engine is a little bit different and even if they were exactly the same, different parts of the country, or even fuel stations in the same town have different additives or gasoline content in the fuel. Using a wideband allows the ECU to see what is happening live and correct for small changes in second to second driving. This feature is called EGO in TunerStudio. It will also allow you to tune your car if you have a laptop and TunerStudio. If you purchase TunerStudio MS, it will also allow you to use an automatic tuning feature called VE Analyze Live – Auto Tune (VEAL for short).

Let’s face it; with the age of these engines very few will have identical pistons, compression ratios, cams or even cylinder heads or valve sizes. This EFI kit can only stretch so far on a base map before it is outside of its usable range. A wideband and at least TunerStudio Lite will help the ECU to do its best fueling using the base map or allow you to tune for any non-original parts in your intake, engine or exhaust.

Narrowband oxygen sensor:

Why do we recommend an expensive wideband sensor when there are cheaper narrow band sensors available? Because, a narrow band can only identify 3 different AFR situations… 14.7:1, richer than 14.7:1 and leaner than 14.7:1. That is all. It cannot tell how much richer or leaner. This is a problem on the MGB engine because it does not run efficiently at 14.7:1 and therefore we don’t ever target that AFR. A wideband on the other hand, can tell you exactly how rich or lean the engine is and the ECU can make adjustments to hit the target AFR.

TunerStudio:

TunerStudio is the program which is used in conjunction with a laptop computer to tune or monitor the Microsquirt used in this fuel injection kit. TunerStudio is not included with this kit. If you wish to monitor what the ECU is doing using your laptop or tune your own vehicle, you must download and install it to your laptop. Visit tunerstudio.com for more information and downloads. Note: if you want to install a wideband oxygen sensor, some version of TunerStudio is required. You must go in the software to enable the MicroSquirt to use the sensor.

MegaLogViewer:

This is program which allows you to data log what the MicroSquirt sees as inputs and also what it outputs. It allows you to drive the car and record what the ECU is seeing and doing. This can be helpful for both tuning and trouble shooting.

Glossary of terms:

.msq- This is the file type the tune is. For instance; if someone asks for your msq in a forum post, they want to see your tune.

AFR- Air fuel ratio or A/R. The ratio of air vs fuel the engine is ingesting.

AN fitting- A fitting made to connect flex hoses with hard parts. This is fitting which has its roots in the American military. The Army & Navy agreed on this standard, hence the name of the fitting.

CLT- Coolant temperature (sensor). Sometimes referred to as ECT (engine coolant temperature). The ECU uses this sensor to determine idle speed and how much fuel to deliver based on coolant temperature. Lower coolant temperature requires a higher idle speed and richer mixture. Think of this sensor as an automatic choke.

ECU- Engine Control Unit or Electronic Control Unit. The Microsquirt computer which runs the fuel system in this kit is an ECU. Sometimes referred to as a PCM (Powertrain Control Module).

EFI- Electronic Fuel Injection

EGO- Exhaust Gas Oxygen. TunerStudio and Microsquirt also use this term to describe closed loop fuel control. If you are familiar with modern cars, think of this feature as "short term fuel trim". An "EGO sensor" is an oxygen sensor.

IAC- Idle air control (motor or valve). This motor is controlled by the ECU and bypasses air around the throttles to control engine speed at idle.

IAT- Intake Air Temperature

Idle- Any time throttle position is less than 1% and idle speed is less than 1600 RPM. Note the tachometer on the dash and the ECU may not agree on engine speed. We have found the tach on the dash can be off by as much as 500 RPM depending on engine speed.

L/H- Left Hand

MicroSquirt- The computer that runs the fuel injection system. See ECU.

MAT- Manifold Air Temperature

R/H- Right Hand

RPM- Revolution(s) Per Minute.

TS- short for TunerStudio.

TunerStudio- A program that allows you to make adjustments to and monitor the Microsquirt.


Moss Europe Ltd.Hampton Farm Industrial Estate

Hampton Road West, Hanworth Middlesex, TW13 6DBIn the UK: 020-8867-2020 FAX: 020-8867-2030

Moss Motors, Ltd.440 Rutherford Street, Goleta, California 93117In the US & Canada Toll Free (800) 667-7872LOCAL (805) 681-3400 FAX (805) 692-2510

For questions or comments please contact:Designed and Distributed by Moss Motors, Ltd.


366-355 BOM

THROTTLE BODIES, PAIR FINISHED

PART# DESCRIPTION QTY

772-982 THROTLLE BODY, SU, NO TPS 1

772-983 THROTLLE BODY, SU, TPS SIDE 1

053-489 FUEL RAIL KIT, TWIN SU FI 1

772-984 BELLCRANK, THROTTLE 1

772-985 BELLCRANK, CLAMP 1

772-869 SCREW, 8-32 X 3/4, PAN HEAD 2

772-934 SENSOR, TPS 1

051-859 SCREW, PHILLIPS, M4X0.7X20 2

772-952 ELBOW, NYLON, 3/8NPT, 1/2"BARB 2

HARDWARE BAG, FUEL SUMP


322-280 BOLT, 1/4 UNF X 2 3/4 3

322-170 BOLT, HEX, 1/4 UNF X 1/2, G5 1

324-590 WASHER, FLAT, 1/4 ID, ZINC 1

051-583 WASHER, LOCK, 1/4" 1

378-125 BANJO UNION, FUEL PUMP 1

370-650 WASHER, FIBER, 11/16 ID 4

772-962 SPACER, FUEL SUMP 3

772-960 3/8" HOSE CLAMP 8

772-961 5/16" HOSE CLAMP 4

772-945 FILTER, FUEL, LOW PRESSURE 1

770-303 WASHER, FLAT, 1/4 ID SAE 4

051-016 CABLE TIE, 4" 30

770-055 CABLE TIE, 6" 20

772-294 P-CLAMP, 2.00" ID,SS, NEOPRENE 1

772-331 SCREW, #8-18, SELF DRILL&TAP 4

770-021 GROMMET, 1-1/2 X 1-1/4" 3

280-190 GROMMET,1/2 ID, 7/8 HOLE 1

053-098 REDUCER, FUEL, 3/8 X 5/16 1

772-226 FUEL RETURN ADAPTER, MGB FI 1

282-920 HOSE, FILLER TO TANK, ANGLED 1

282-620 HOSE, FUEL FILLER TO TANK 1

326-460 CLAMP, HOSE, WIRE TYPE, 2-1/4" 4

770-577 NUT, NYLOC, 1/4 UNF 3

315-055 WASHER, FLAT, #10, ZINC 1

370-650 WASHER, FIBER, 11/16 ID 2

772-742 SLIT LOOM, CONVOLUTED, 3/4 DIA 24

HARDWARE BAG, THROTTLE BODIES


696-100 GASKET, CARB TO MANIFOLD 2

191-915 BOLT, HEX, 5/16 UNF X 1 1/4 4

051-587 WASHER, LOCK, 5/16" 8

770-023 BOLT, HEX HEAD, 1/4UNF X 1-1/4 1

294-710 GASKET, CARB MOUNT 6

772-957 COUPLER, SHAFT, 5/16" 1

462-411 FITTING, FUEL INJECTION, -6AN 1

770-812 NUT, STANDARD, 1/4-28 2

052-339 NUT, STANDARD, 5/16 UNF 4

772-949 INJECTOR, FUEL, 35#/HR 2

772-928 ADAPTER PLATE, 40MM T-BODY 2

051-588 WASHER, FLAT, 5/16", SAE 4

772-307 BOLT, 5/16-18 X .625, HEX HD 4

772-930 BRACKET, THROTTLE CABLE 1

331-466 CABLE, THROTTLE, LOW FRICTION 1

372-062 GUIDE, THROTTLE CABLE FOR FI 1

772-990 MICROSQUIRT, W/ BASE TUNE 1

772-991 HARNESS, MSQUIRT, COMPLETE 1

772-992 HARNESS, SUB, FUEL PUMP, FI 1

772-936 SENSOR, CLT 1

053-439 COOLANT TEMPERATURE BLOCK 1

772-938 SENSOR, IAT 1

772-946 NUT, 3/8" NPT, NYLON 1

772-940 SENSOR, MAP, 1 BAR 1

052-211 HOSE, VACUUM, 1/4, BULK 18

772-958 SUMP KIT, FUEL 1

900-240 SWITCH, INERTIA, FUEL CUTOFF 1

051-260 HOSE, FUEL INJECTION,3/8 IN ID 228

051-262 HOSE, FUEL, HP, 5/16", BULK 156

053-457 FUSE BLOCK, 6-PLACE 1

053-458 FUSE, BLADE-STYLE, 10 AMP 1



772-271 SPADE,PIGGYBACK,1 M TO 2 MALE 3

HARDWARE BAG, THROTTLE BODIES CONT.


053-464 BOSCH IDLE AIR CONTROL VALVE 1

462-412 P-CLAMP, LOOM, 1-7/8" ID 1

772-953 HOSE, PCV/EVAP, 3/4" I.D. 8

367-460 HOSE, EMISSION, PER INCH, 1/2 18

051-009 BRACKET, HOOD 1

697-360 GASKET, HEATER TAP 2

052-286 BOLT, HEX, 1/4-28 X 1.5 2

053-452 FILTER, AIR, BOSCH IAC 1

771-370 WASHER, FLAT, M6 X 18MM OD 1

772-951 TEE, VACUUM, PLASTIC 1

772-953 HOSE, PCV/EVAP, 3/4" I.D. 10

367-460 HOSE, EMISSION, PER INCH, 1/2 18

052-339 NUT, STANDARD, 5/16 UNF 1

051-587 WASHER, LOCK, 5/16" 1

770-812 NUT, STANDARD, 1/4-28 1

051-583 WASHER, LOCK, 1/4" 3

770-303 WASHER, FLAT, 1/4 ID SAE 1

322-920 BOLT, HEX HEAD 1/4-28 X 3/4 1

322-175 BOLT, AIR FILTER, 5/16-UNCX4.5 4

772-053 CAP, VACUUM, RUBBER, 5/32 2

051-242 CAP, VACUUM, RUBBER, 5/16 2

051-777 VELCRO, 1" WIDE, BULK 30

053-469 INSTRUCTIONS,TWIN SU FUEL INJ. 1

366-355 BOM

Documents

Cobalt DRIVE EFI - Moss Motors · this EFI kit. For 1970 and later, you will need to purchase and install Moss’s PCV kit part# 366-395 or come up with your own solution. This EFI