I have a 97 LT1 with no spark. I have scanned for codes with my OTC monitor but have none. There is no sinificant voltage change on my DVM in max hold on DC, or AC voltage on AC on the ICM Ignition Control pin. My monitor looses data communication when cranking so I haven't been able to check for the low resolution signal from the optispark. Has anyone looked at the low and high resolution signals on a DVM? We are recharging the battery so we can test for an Optispark failure. I want to be sure before we replace it. We have also been able to try several PCM's and they did not correct the no spark. Any troubleshooting help would be appreciated.

 

Check your coil. If there is spark going into the opti but nothing coming out then the opti is your problem.

 

There is no spark out of the coil or any signal to the Ignition Control Module. My understanding of the system is that either the PCM has a problem, which we changed, or there is no signal from the optical sensor in the Optispark. I was already at the Optispark in my troubleshooting. Correct me in my troubleshooting if I'm misunderstanding the system. I am an Engineer also.

 

I originally was thinking rotor failure so it does sounds possible the optical sensor has gone bad or you may have a bad connection from the harness.