Backstory: Much to my wife's chagrin, my 18 year old son and I bought a 2 owner 1992 coupe that hadn't run in 10 years. Supposedly, the owner was having optispark issues. It quit on him, was towed home, and over the winter had some health problems and wasn't able to work on it. He gave the car to his son in law who basically had no interest in fixing it and it sat for the next 10 years. He was losing his storage space and put a for sale sign on it, and we looked at it. Other than clearcoat failure, dry rotted tires, and weatherstripping rot, it was a solid car. Interior was decent, no real body damage, etc. so we made a deal and pushed it up on our trailer and brought it home.

First thing we did was drop the tank, cleaned it out, installed new pump and sender assembly, and fresh gas. Then we changed plugs and wires. We had no spark. We changed the optispark, still no spark. Changed the icm and coil, still no spark. Sent the ECM to SIA for rebuild. Still no spark. Swapped the coil and ICM from a 95 ImpalaSS parts car I have been holding onto for some unknown reason. Still no spark. Obviously we have checked the fuses and verified voltage at the coil. We have no spark and no injector pulse. ECM shows code 41. CCm shows code c41, h41, ERR on module 4, and H72 on module9. We can't find any chewed wires, can't find loose ground. We have good oil pressure and a new battery. Everything is pointing to the ECM, but like I said, it is fresh from SIA. We have it hooked up to tunerpro and have RPM signal, so the optispark must be working.

Does anyone have any ideas on where to go from here? Does anyone in the Cincinnati / Dayton area have a 92 I can drop my ECM in to verify its function. I know that is a lot to ask, but this father son project has us both very frustrated.

 

You said you changed the opti. Where did you get the replacement opti? Do you know what brand it is. Some of the less expensive ones from China not only don’t last long but flat out don’t even work right out of the box.

I don’t know how to instruct you to diagnose the opti specifically but there are others on here who can. Hopefully they will chime in and tell you what wires to check for what signals.

Verifying if that replacement opti is any good is the first place I would start giving everything else you’ve done so far.

Good luck. I’ll be watching this thread and hoping with you.

 

Bing Videos

Also google search how to test the coil. Dan

 

I would verify the Opti is doing what it should first. I can tell you that I had my ECM repaired by SIA a year or so ago......to basically work on and off correctly for a short period and then crapped out again. I sent it back to them for warrantee fix. They said they tested and reflowed again. I actually haven't put in my car since, as while it was being repaired I bought a working backup ECM and swapped my chip to it. Car has run perfect ever since. Along the way though I did replace my Opti, ICM and coil as mine were chinese crap, and other mismatched aftermarket parts that didn't work well either in my testing. Service manuals helped me with all that. Best of luck.

 

You 'Could' buy another opti and the extension cable and then plug them into your car. Turn the key to the on position and spin to win! Turning the Opti by hand will fire the injectors and coil and you should hear audible clicks to ensure the ECM is good. Where the dist. rotor stopped will fire that cylinder, you could set the the engine to Cyl 1 TDC and check that plug but I usually put a spark check right on the coil.

Often when the inexperienced work on the Opti in-situ they bend pins on the connector so the engine cant get the hi or low res signals from the opti.

Typically, when the ECM goes bad the cooling fans run as soon as the key it turned on or SES lamp will flash.

 

Good point on that last sentence ECM.....my car did just that, as soon as the key was on my cooling fans both were on, and sys flashing.