7/26/2019 Ignition Set Up Modis
1/2
Make sure you select Plug for Number 1 Trigger along with the
settings for the
ignition type, Number of cylinders, and firing order.
The ray !PM"#yl1 lead is used to sync the $gnition %cope to
#ylinder &1. $t connects
to the ' pin connector on the unit and to the &1 plug wire
on the (ehicle
This allows the $gnition %cope to display the cylinders in the
correct position on the
screen.
There aren)t any other settings to ad*ust when using with this
lead.
The signal from it is not displayed on a channel.
$t is basically an e+ternal trigger for the scope and is also
used for !PM calculations.
To determine if the signal from the !PM lead is ok, disconnect
your secondary lead
from channel1 and only connect the !PM lead.
$f !PM is displayed consistently and matches the engine !PM, you
ha(e a goodusable signal coming in from the !PM lead.
$f it is not, try mo(ing it to a different position on the plug
wire.
The reason you ha(e to remo(e the secondary lead for this check
is the signal from it is
also used to calculate !PM.
The only other setting specific to $gnition %cope that may need
to be ad*usted is the
secondary detection threshold.
$t works the same as on the antage Pro or Modis.
$t sets the sensiti(ity of the ignition scope to detect ignition
firings input to the scope on
#h1 -#h1 and for /aste spark ignition0 from the ignition
lead.
$t does notwork like the signal le(el based trigger in lab scope
where the e+act le(el
that will trigger the scope is set.
$t takes into account other characteristics of the secondary
wa(eform than *ust the
le(el.
The setting is displayed along the left side of the grid as a
right facing triangle. $t can be
mo(ed up and down as needed. ou can drag it or mo(e it using the
control on the
Trigger %etup window. 2igher 3 less sensiti(e, lower 3 more
sensiti(e. My rule of
thumb is to set itat the a(erage spark (oltage to start
-Typically 141.5k0.
$f it is set too low, the scope may detect e(ents on the
wa(eform that are not firingssuch as coil current limiting in the
dwell section, the start of dwell, or oscillations.
$f it is set too high, it will miss cylinders.
There are some e+amples in one of the appendi+ sections at the
end of the Modis
manual found here6
http://www1.snapon.com/diagnostics/us/UserManuals
The best thing to do once you get a (ehicle connected and
working correctly is to mo(e
the threshold down until the pattern starts to break up and
obser(e what happens.
Mo(e it up until it stabili7es, then continue mo(ing it up until
cylinders drop out and
obser(e what happens. 8nce you obser(e this, you will ha(e a
much better idea how itworks and needs to be set.
http://www1.snapon.com/diagnostics/us/UserManualshttp://www1.snapon.com/diagnostics/us/UserManuals
