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starting issue need some help

L

LI22limited

NAXJA Forum User
Location
patchogue
other day i was diving doing about 70 on the park way and my truck just shut off and wouldn't start back up ... im getting a good crank and fuel ...but only sparks like 3 times and then no spark ... replaced the cps .. and the coil to no avail ... im kinda stumped at the moment ... i was thinking distributer or the ecm . I could use some help thanks in advance
 
We need to know the year, any mods, etc.
 
it does not have an alarm .. it has auto locks and auto start tried locking and unlocking automatically and manually with the key .. disocnnected the auto start and auto lock device still no change
 
You said "disconnected" the auto start--did you mean that you completely disconnected it and put the wiring back to OEM?
 
Yes. 91 is an HO model and has sequential fuel injection. Unlike the renix model, it will not start without cam signal. Renix models will extend crank and then start in non-sequential mode if no cam signal is found.
 
Digger87xj said:
Yes. 91 is an HO model and has sequential fuel injection. Unlike the renix model, it will not start without cam signal. Renix models will extend crank and then start in non-sequential mode if no cam signal is found.
Click to expand...

Thanks!!!! I will try to remember that that detail!

So why does it give spark at all (91+)? Is it the sensor signal coming and going, or does it spark a few times first then shut down if the sync sugnal is missing? In other words why would it spark at all, unless the signal was intermittent?
 
The cam sensor only sends a signal once per revolution of the distrib/cam. That's two revs of the crank. So initially, the pcm will turn on the ASD relay which powers the injectors, coil, fuel pump relay and O2 heaters as soon as it sees a cranking signal, which is almost immediately. It uses the cam signal to sync number one cylinder intake stroke with #1 injector. After a few rotations of the crank and no signal from the cam sensor, the PCM shuts down the ASD relay to prevent back and after- fires.
 
Digger87xj said:
The cam sensor only sends a signal once per revolution of the distrib/cam. That's two revs of the crank. So initially, the pcm will turn on the ASD relay which powers the injectors, coil, fuel pump relay and O2 heaters as soon as it sees a cranking signal, which is almost immediately. It uses the cam signal to sync number one cylinder intake stroke with #1 injector. After a few rotations of the crank and no signal from the cam sensor, the PCM shuts down the ASD relay to prevent back and after- fires.
Click to expand...

Thanks!!! So does it guess and feed some fuel initially while it looks for the sync signal, or not?

Sounds like you have answer on the sync signal for his problem!!!!
 
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