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ATASA 5 th Electronic Fuel Injection ATASA 5 TH Study Guide Chapter 30 Pages 899921 Electronic Fuel Injection 68 Points
Please Read The Summary
1. EFI systems are ________ controlled and designed to provide the correct _________ ratio for all engine loads, speeds, and temperature conditions.
ATASA 5 th Electronic Fuel Injection
Computer Mechanical Hydraulic
2. The ideal air/fuel ratio is called the _________________ ratio and consists of 14.7 parts of air to 1 part of fuel by weight. Note: Different fuels have different stoichiometric ratios.
Stoichiometric Basic Advanced
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
3. The stoichiometric ratio allows the ____________ converter to work most efficiently.
ATASA 5 th Electronic Fuel Injection
Catalytic Cadillac Catatonic
3. The stoichiometric ratio allows the ____________ converter to work most efficiently.
Catalytic Cadillac Catatonic
ATASA 5 th Electronic Fuel Injection
Catalytic Converter Efficiency
4. A _________ _________ system determines the amount of air entering the engine with input from the MAP (manifold absolute pressure) (piezo resistive Vref) sensor and the RPM sensor.
ATASA 5 th Electronic Fuel Injection
Speed Density Mass Air Flow Carbureted
5. Most engines use a _________ __________ system (MAF) to measure the amount of incoming air.
Mass Air Flow Mass Fuel Flow Mass Any Flow
ATASA 5 th Electronic Fuel Injection
6. During __________ ________, EFI systems rely on input from various sensor before adjusting the air/fuel ratio. (warm coolant, time running, & using active upstream HO2S signals)
ATASA 5 th Electronic Fuel Injection
Open Loop Closed Loop Fail Safe
7. During ________ ________, EFI systems deliver fuel according to predetermined parameters held in the PCM’s memory. (cold coolant, time running, & ignoring inactive upstream HO2S signals)
ATASA 5 th Electronic Fuel Injection
Base Command
Exhaust Base Pulse
Width
Working at Base Fuel Trim
Number is Zero .450 volts
Feedback System in Closed Loop Mode
7. During ________ ________, EFI systems deliver fuel according to predetermined parameters held in the PCM’s memory. (cold coolant, time running, & ignoring inactive upstream HO2S signals)
ATASA 5 th Electronic Fuel Injection
Rich Command
Lean Exhaust
Pulse Width Δ
Richened Fuel Trim Positive #’s
.1 to .4 volts Low Numbers Lots of Oxygen Lean Exhaust
Feedback System in Closed Loop Mode
7. During ________ ________, EFI systems deliver fuel according to predetermined parameters held in the PCM’s memory. (cold coolant, time running, & ignoring inactive upstream HO2S signals)
ATASA 5 th Electronic Fuel Injection
Rich Exhaust
Lean Command
Pulse Width Δ
.5 to .9 volts
Less Oxygen
Leaned Out Fuel Trim
Negative #’s
Feedback System in Closed Loop Mode
8. Fuel _______________ are solenoids with movable armatures that pulse on when electricity flows through their internal coil of wire. This action delivers a spray of atomized fuel.
Relays Transformers Solenoids
ATASA 5 th Electronic Fuel Injection
9. Orings on injectors seal them into the intake ________________ and the fuel __________.
Manifold, Rail
ATASA 5 th Electronic Fuel Injection
10. Injectors are fed ______________ voltage and are pulsed on by the PCM controlling the driver circuit ground.
Battery 5 VRef Secondary
ATASA 5 th Electronic Fuel Injection
11. The length of time that a PCM grounds the injector to turn it on is called ________ _________.
Pulse Width Fuel Trim Duty Cycle
ATASA 5 th Electronic Fuel Injection
Injector Signature or Voltage Waveform
Injector Current Ramp Waveform
12. Injector pulse width is expressed in _________________ of ontime. (Fuel Trim = adjustment)
Nanoseconds Milliseconds Seconds
ATASA 5 th Electronic Fuel Injection
12. Injector pulse width is expressed in _________________ of ontime. (Fuel Trim = adjustment)
Nanoseconds Milliseconds Seconds
ATASA 5 th Electronic Fuel Injection
13. Pulse width can range from 1 to 10 milliseconds. Cold starting requires a ________ pulse width.
Shorter Medium Longer
ATASA 5 th Electronic Fuel Injection
Clear Flood Base
Lean Rich
14. Idle speed is controlled by ________________ a certain amount of airflow past the throttle plate.
ATASA 5 th Electronic Fuel Injection
Surrounding Bypassing Rejecting
15. __________ ______ _____________ motors (IAC) are stepper motors used to control idle rpm.
ATASA 5 th Electronic Fuel Injection
Idle Air Control Idle Speed Control Idle Shut Down
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
16. Throttlebywire systems use a throttle actuator motor (TAC) instead of an IAC. True or False
ATASA 5 th Electronic Fuel Injection
17. The ________ ____________ sensor (MAF) calculates the mass of a given amount of air by multiplying its volume by its density. (measured & expressed in grams/second or # per minute)
ATASA 5 th Electronic Fuel Injection
Mass Air Flow
18. Base pulse width of injectors can also be determined by a ___________ ____________ _____________ (MAP) sensor which calculates engine load using manifold vacuum.
ATASA 5 th Electronic Fuel Injection
Manifold Absolute Pressure
19. At closed throttle the engine has a ____ MAP value. At WOT a ______ MAP value is produced…Opposite of Vacuum!!
Low, High High, Low Little, No
ATASA 5 th Electronic Fuel Injection
20. MAP output is the ____________ of what is measured on a vacuum gauge.
Opposite Same Reciprocal
ATASA 5 th Electronic Fuel Injection
21. The MAP signal is also used to inform the PCM when the ______ valve is open since introducing exhaust into the intake manifold would affect pressure in the manifold.
EGR PCV CNP
ATASA 5 th Electronic Fuel Injection
22. The MAP signal could be used to determine turbo boost. True or False
ATASA 5 th Electronic Fuel Injection
EGR Raises Manifold Pressure
Turbo Boost Really Raises Manifold Pressure
23. Manifold Absolute Pressure equals the _______________ pressure minus the intake manifold ______________. Expressed in inches of mercury (Hg”) BARO – VAC = MAP
Barometric, Vacuum Vacuum, Barometric Sea Level, Gravity
ATASA 5 th Electronic Fuel Injection
minus
24. Signals from the exhaust gas ________ (O 2 S) sensors are the main input to adjust the A/F ratio.
Oxygen Hydrogen Krypton
ATASA 5 th Electronic Fuel Injection
Voltage Range:
.1 to .9 Volts DC
100 mV = Lean Exhaust Results in: Rich Fuel Trim Command
900 mV = Rich Exhaust Results in: Lean Fuel Trim Command
ATASA 5 th Electronic Fuel Injection
B1 S1 HO2S Upstream = PreCAT AirFuel Ratio Management
B1 S2 HO2S Downstream = PostCAT Catalyst Efficiency Monitor
Exhaust Flow
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection 25. Low voltage at the HO 2 S is a ______ exhaust indicator resulting in a rich
injector command
Lean Stoichiometric Rich
26. High voltage at the HO 2 S is a ______ exhaust indicator resulting in a lean injector command.
ATASA 5 th Electronic Fuel Injection
Lean Stoichiometric Rich
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
Catalyst Efficiency Comparison of Upstream & Downstream HO2S
A good CAT should have a flat pattern on the S2 HO2S
ATASA 5 th Electronic Fuel Injection
27. Intake ______ temperature sensors (IAT) are necessary since ________ air is more dense than warm air, it can burn more fuel than the same volume of warm air.
Fuel, Cold Air, Cold Heat, Cold
ATASA 5 th Electronic Fuel Injection
28. The engine ___________ temperature sensor (ECT) signals the need for cold A/F enrichment.
Fuel Air Coolant
ATASA 5 th Electronic Fuel Injection
29. The ____________ position sensor (TPS) is a potentiometer.
Coolant Intake Throttle
ATASA 5 th Electronic Fuel Injection
30. The highly important _______________ position sensor (CKP) monitors engine speed.
ATASA 5 th Electronic Fuel Injection
Camshaft Crankshaft Balance Shaft
31. The _________________ position sensor is used to synchronize the timing of injector pulses.
ATASA 5 th Electronic Fuel Injection
Camshaft Crankshaft Balance Shaft
32. ____________ mode sets injector pulse width using MAF, IAT, ECT, & TPS.
Starting Open Loop Closed Loop
ATASA 5 th Electronic Fuel Injection
33. _________ mode can be either open loop or closed loop based on ECT, HO 2 S, and TPS.
ATASA 5 th Electronic Fuel Injection
Starting Run WOT
34. A system with 0 milliseconds of pulse width during cranking is in ________ ________ mode.
ATASA 5 th Electronic Fuel Injection
Closed Loop Deceleration Clear Flood
35. There are also ________________ & _______________ modes to respond to rapid TPS change.
Acceleration, Deceleration Liftoff, Splashdown Intake, Exhaust
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
36. Adjustments made to base pulse width are called fuel ________. A positive fuel trim is an increase in pulse width. A negative fuel trim is a decrease in pulse width.
Trip Trim Brim
ATASA 5 th Electronic Fuel Injection
37. ______ term fuel trim (STFT) represents changes made immediately in response to HO 2 S signals.
Short Medium Long
ATASA 5 th Electronic Fuel Injection
38. _____ term fuel trim (LTFT) represents changes made to a new base pulse width by STFT trends.
ATASA 5 th Electronic Fuel Injection
Short Medium Long
39. STFT is __________ when the ignition is turned off. LTFT remains in the PCM memory.
Reset Rebuilt Refused
ATASA 5 th Electronic Fuel Injection
40. Low pressure _____ systems used 1 or 2 injectors above a throttle plate centrally located atop the intake manifold. Throttle body injection was the transition from carburetors to port injection.
TBI CMFI TRI
ATASA 5 th Electronic Fuel Injection
41. ______________ injection (MPI) locates the injectors close to the valves in the intake manifold, but pulses all injectors at the same time or in banks on engines with V cylinder arrangements.
Multiport Multicylinder Multirail
ATASA 5 th Electronic Fuel Injection
42. ______________ (SFI) controls each injector separately, firing just before the intake valve opens.
Sequential Special Supersonic
ATASA 5 th Electronic Fuel Injection
43. Port injection systems have a ___________ _______ to control the amount of incoming air.
ATASA 5 th Electronic Fuel Injection
Throttle Body Air Injector Throttle Pedal
44. Idle speed is adjustable with a screw on the port injection throttle body. True or False
ATASA 5 th Electronic Fuel Injection
45. Injectors are fastened to the fuel ________ which is a fuel manifold or distribution device.
Rail Snail Tail
ATASA 5 th Electronic Fuel Injection
46. Fuel pulsation __________ are used on some rails to reduce fluctuations and to quiet operation.
Dampers Tampers Hampers
ATASA 5 th Electronic Fuel Injection
47. Vacuumsensitive fuel pressure _________________ maintain constant pressure drop of the injectors.
Restrictors Regulators Resonators
ATASA 5 th Electronic Fuel Injection
48. On Throttlebywire systems, a throttle actuator __________ responds to input from accelerator pedal position sensors (APP). There are redundant APP and TPS in a throttlebywire system.
Motor Engine Pedal
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
49. CMFI uses individual ________ _____________ for each cylinder controlled by a single injector and a fuel pressure regulator mounted right on the CMFI module.
Poppet Nozzles Poppet Valves Poppet Sodas
ATASA 5 th Electronic Fuel Injection
50. CMFI injector pressure is regulated very accurately between ____ to ____ psi. This eliminates vapor lack tendencies, but makes the system sensitive to low fuel pressure problems.
37 43 psi 48 56 psi 54 64 psi
ATASA 5 th Electronic Fuel Injection
51. ____________ __________ _________ (GDI) has advantages over SFI, such as precise delivery and the system’s ability to learn the fuel type & adapt to another stoichiometry.
ATASA 5 th Electronic Fuel Injection
Gasoline Direct Injection Great Direct Injection Good Direct Injection
52. GDI injectors deliver fuel ____________ into the high pressures & high temperatures in the cylinder.
Directly Indirectly Easily
ATASA 5 th Electronic Fuel Injection
53. Piezoelectric injectors that rely on stacked _____________ have a faster response time than solenoidtype injectors. They react so fast that they can pulse multiple times in one engine stroke.
ATASA 5 th Electronic Fuel Injection
Crystals
54. GDI fuel rail pressures can range from ______ to ______ psi!
435 1,885 psi
ATASA 5 th Electronic Fuel Injection
55. GDI can operate in ______ burn, _____________, or ______ __________ mode.
Lean, Stoichiometric, Full Power
ATASA 5 th Electronic Fuel Injection
56. For increased mileage, GDI can run as lean as 60:1 using ____________ charge combustion.
Nullified Stratified Pacified
ATASA 5 th Electronic Fuel Injection
57. GDI engines can operate at higher _____________ ratios without the need for high octane fuel.
Compression Air:Fuel Axle
ATASA 5 th Electronic Fuel Injection
58. To meet OBDII standards, diesel engines use __________ rail injection systems with many of the same inputs as gasoline engine and piezoelectric injectors. Rail pressures are 2,000 to 25,000 psi!
ATASA 5 th Electronic Fuel Injection
Common Uncommon NonCommon
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
A. System Voltage B. Injector On C. Injector Off D. Inductive “Kick”
B to C. Pulse Width
ATASA 5 th Electronic Fuel Injection
www.picotech.com This is an amazing site for Automotive Diagnostics!
Under the Automotive Heading, go to the Waveform Library!!
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
http://www.cf.ac.uk/engin/staff/pjb/source/GDIanim.gif
Click Here!
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
Manometer or UTube. Contains Mercury (Hg) measured in Inches
ATASA 5 th Electronic Fuel Injection
Abbreviation Full name of sensor Type of sensor MAF Mass Air Flow [ ] active (freq gen) [ ] passive MAP Manifold Absolute Pressure [ ] active [ ] passive TPS Throttle Position Sensor [ ] active [ ] passive ECT Engine Coolant Temperature [ ] active [ ] passive IAT Intake Air Temperature [ ] active [ ] passive KS Knock Sensor [ ] active [ ] passive CKP Crankshaft Position [ ] active [ ] passive CMP Camshaft Position [ ] active [ ] passive EGO Exhaust Gas Oxygen [ ] active [ ] passive (B1 S1) Bank 1 – Stream 1 HO2S (PreCAT) HEGO Heated Exhaust Gas Oxygen [ ] active [ ] passive (B1 S2) Bank 1 – Down Stream (PostCAT)
ATASA 5 th Electronic Fuel Injection
MAF MAP Hot Wire or Hot Film
High Frequency Generator PiezoResistive (3wire)
5 Volt Reference
ATASA 5 th Electronic Fuel Injection
TPS KS 5Volt Reference (3 Wire)
Potentiometer PiezoElectric Generator
Quartz Crystal
ATASA 5 th Electronic Fuel Injection
IAT
ECT Negative Temperature Coefficient (NTC) Thermistors 5 Volt Reference (2Wire)
ATASA 5 th Electronic Fuel Injection
CKP CMP Permanent Magnet Generators (2Wire) Analog Output
Or HallEffect Generators (3Wire) Digital Output
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
HO2S
Galvanic Cell Uses Zirconia exposed to 2 Different Atmoshperes to Produce Voltage
ATASA 5 th Electronic Fuel Injection
Voltage Range:
.1 to .9 Volts DC
100 mV = Lean Exhaust Results in: Rich Fuel Trim Command
900 mV = Rich Exhaust Results in: Lean Fuel Trim Command
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
WideRange Air:Fuel Sensor
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection
ATASA 5 th Electronic Fuel Injection