I've just installed a 95 Camaro LT1 in a 68 Camaro. The engine has good fuel psi., but no spark. The coil has power but no ground. I've checked the ICM pins and have 12 volts on A & D. Ground on pin C, but no ecm signal on B.
Checked opti. connector and have 12 volts on C , 5 volts on A and B, and ground on D. I get 1 flash on the ground side of injector 1 during start cycle then nothing during engine crank. The harness is "aftermarket" and the ecm was programed with vtss removed. I think the vtss is causing my problems.
Can anyone help? (new icm and coil did NOT help)

 

Could be your opti is not putting out the reference signal to the PCM or the PCM is not putting it out to the ICM (though PCMs rarely fail). By vtss, do you mean VATS? Have you checked for any trouble codes? You should.

 

yes i meant "VATS". Today as a test I installed my PCM in a running car, and it fired-up on first crank. so... maybe the opti ? The only thing that's bugging me is the fact that the engine ran great when i pulled it. The only difference is the harness. I've not checked for codes, but that will be the next thing on my list. I did check for signal at the PCM (black connecter pin 5, and no signal to the ICM) That's why I checked volts and ground at the opti connector. I still want to talk to the guy that made my harness, some of the connecters to the 6 speed don't match up, and remain unpluged. Could that be part of my problem ?
By the way thank you so much for your help, your home page rules!