Indianaboyd94

So I recently picked up a 96 firebird ws6 with the lt1. I'm not getting any spark and I've replaced the icm, the coil, and the opti. I've already tested the signal to the icm harness and everything checks out there. When I checked the opti harness with the key on I got 5v at pins A and B but I got nothing on pin c. I got no resistance on pin D with the key off. I suspect it's either a bad pcm ground or the pcm itself ( guessing it's probably not the pcm because I have reference signal at icm). I plan on checking the pcm ground and plug connections later today but beyond that I'm at a loss. Any ideas?

Indianaboyd94

Also I have no injector pulse

Injuneer

When you tested the ICM signal, did you get 1.0 to 4.0 volts AC on the white wire at pin B?

Where did you check for spark - at the coil wire, at a few plugs, or both?

If you got 0 volts on pin C at the Opti, there was no power to the Opti. I think that would prevent the Opti from sending the pulse signals to the PCM. No pulse = no spark, no injector pulse. But if that was the case, you wouldn't get any AC volts on the white wire to the ICM.

At any point did you scan it for codes?

Indianaboyd94

I got it figured out. Tested continuity on the wire on pin c at the opti and on the plug to the pcm and found out it got cut in the harness. Spliced it together and it fired right up. Would have been nice to know a few hundred dollars ago haha

Injuneer

Glad you found the problem.

Hopefully you bought a high quality Opti like the AC Delco. Most everything else is a crap shoot.