No Ignition pulse to coil (or ignition module)

[Motorsports-X]

Hey guys,

I have a no spark condition on my truck. 96 k1500. 5.7. the coil and ignition module both test good, but i stuck a new module on it just in case, to no avail. After inspection, I found that the signal wire going to the coil does not pulse at all. in fact it does nothing. I checked the signal wire from the PCM to the ignition module, and it is not pulsing either. It simply provides a full ground (12v per the multimeter) and then when you crank it goes down to 9v. I am not sure if this wire is supposed to pulse like the signal wire going to the coil does, but I THOUGHT that was how the ecm fired the coil. (by breaking continuity/ground on that signal wire to the ignition module)

All other grounds, hots, continuity etc all are ok (at least that i can find) no blown fuses, and when you plug the ECM back into the harness everything comes to life.

Any ideas?

 

[east302]

Here’s a link that might help, it looks like they cover the testing of the coil/module and CKP sensor for a 350 vortec...

https://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/ignition-misfire-diagnostic-tests-5


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[Motorsports-X]

I pretty much did exactly what that thing said, just from memory. the only thing i might of done wrong is checked the pcm to ignition module signal wihtout the IM being plugged in. I will check it in the morning, but I already know im not getting signal out of the old or new ignition module by checking the coil signal wire.