First off my car is a 200k mile 1995 M6 with headers, CAI, and stock PCM tune. Right before I got the car 3 years ago the optispark was replaced with an AutoZone special and the plugs/wires were changed. The car has had random stutters at low RPM's and high loads the entire time I have had the car. However I have only put a few thousand miles on it so I haven't messed with it. The other day my brother was in it and it died when he was trying to leave. He thought it was out of gas so put some in and it fired up. He later told me and I knew it had gas so I tried to drive it. It drove fine then all the sudden it just shut down. It was turning over and had fuel pressure, but just would not fire. Finally after about 15 minutes it fired up. I drove it straight to my dad's shop "~2 miles" and right before I got there it started sputtering.

I was aggravated so I let it set for about 2 weeks. Finally I went to go check it out and it would not crank. After trying 7 or 8 times it finally fired off. Drove it into the shop and the fuel checked good. It ran fine and I shut it off and cranked it several times that evening. Then next day I went to go back it out and it would not crank. Pulled a plug and it wasn't sparking at all. We have tried to crank it several times over the last few days now and it will not fire off at all anymore.

I have a spare LT1 engine so I pulled the ICM and Coil off it and swapped with mine and of coarse it did not fix it. I will be doing the Optispark test like shown in this write up http://shbox.com/1/4th_gen_tech2.html#opti_test this weekend. Maybe this will tell off on it. Does anybody have any thoughts or suggestions? Also does all 95's have vented opti's or does the early 95's have the older style? From what I have read if I need to replace the opti and mine is vented the GM Delphi is the way to go, does every one agree? Any help will be appreciated.

Thanks,
Chase

 

Anyone?

 

Do the tests, but sounds to me like the opti. Swapping the coil/icm should have resolved the issue if they were at fault, but since they didn't the opti tests are next. But you said that the car had low and mid rpm misses, plus it is a autozone opti. Best part of that is that is should be a warranty issue with Autozone. Post results and let us know

tia

andy schuck

 

Thanks,

Did the test and I appear to have good values going to the ICM, but I do not get the proper voltage while trying to crank. So I believe this means that the optical part of the optispark is not picking up signal there for not the PCM is not sending the pulsing voltage to the ICM to fire the coil. Or the PCM/harness could be bad, but I am going to be optimistic and hope it is the opti. The new one from GM is on its way and will be going in this weekend.

 

Do u have a security light on?

 

No, what would this mean if I did/didn't? I have known the car for a while and way before I owned it the previous owner had some problems with the security. It seems like the light would come on and the car would not do anything and he would just wait 10 or 15 minutes and it would crank up fine. I think this is how it went however I am not able to find out any more.

 

It's been a while, but I would just like to let everyone know it was the optispark. I replace it and now it runs like a champ. Just wanted to put some closure on the post in case someone needs the info one day.

 

Thanks for the update. It sure would be nice if everyone tried the "closure" routine. Many times suggestions are given and the OP never posts again.

 

Security light would likely mean the VAT's , But yes go with a GM stock replacement Opti. I'm sure someone can tell you the cheapest place to get one