So about a year back I sold my 93 Z28.... Shortly after selling it to a friend of my sons'...the guy started having issues with the car randomly stalling out and dying on him. I tried to help him out, but never could figure out what the problem was..... Car will run perfectly for 2 or 3 days, then suddenly it dies on him. No ryme or reason really.

The guy put around 3000 miles on the car in the time hes owned it. Has breand new rear tires on it now and a broken console lid, which it didnt have when he got it....

Long story short, I sold it to him for $4500. We agreed I would buy it back for $3000.

The car is the one in my avatar... LT-1 6 speed.

So, now where should I begin on troubleshooting?

Some info:

The car had the Opti replaced with an MSD unit before I purchased it....however, it might have gotten wet at some point in the time the guy had it.... (about a year back this happened in some heavy rain we had)

He replaced the MAP sensor.
I checked fuel PSI for him and it was perfect both running and KOEO
My guesses are: Optispark, cam sensor, crank position sensor, or ECM???

Anyway, I pick the car up next Sunday about 90 miles from my house...Im getting a trailer just in case she decides to be a beotch!

Any help I could get from you guys would be awesome...Even though I wont have the car til next week, Id like to start looking at the fix for this issue!

Thanks a million!!

 

replace the ignition coil/control module.

 

ICM like Craby said or it's possible the opti is kicking the bucket again, but I'd leave that as a worst case. Don't have to worry about crank sensor since '93 doesn't have one and opti acts as the cam. As far as the opti, was the whole unit replaced with a MSD or just the cap?

 

It was the whole thing with the billet body. Nice piece really... It was done in the last 5000 miles....

Who makes a good quality ICM and coil for it?

 

Going up to Denver tomorrow with my son.... 4am!! I should be back by 10:00 (ish) Then its off to Pueblo for a Mothers Day lunch at Red Lobster!!! Finally Ill be home to start looking over my toy!

 

Ok, so heres how it went when picking up the car. It was cold and rainy... From a dead cold start, it cranked and tried to start. This went on for about 15 minutes...sometimes it would fire and run VERY rough as if you had a spark plug wire crossed.... I tried feathering the throttle while starting which helped it some, but still it would die.

I decided to quickly install a new ICM which I brought with me. Seeing that there were no rivets holding it on, I knew it had been changed already.....I installed it anyway. The night before, I had read through some of my old Emails from the seller when I bought it and saw where he had changed the coil with a new one.

The replacement ICM did not work...


Finally she fired up, cleared out and ran fine. We shook hands and off we went.... or so we thought ..... About 2 minutes later, she stalled out again...started on the second try though. A 100 yards or so, it happened again....

At this point I figured let me get it on the trailer. I fired it up and it started perfectly and ran like nothing was ever wrong. I told my son, lets give it one more try to get it home....

Wouldnt you know it, she ran like a top for 90 miles to my house...light traffic and stop lights included....

So now I am really not sure where to go from here. Extracting codes is what I think Ill try next... I checked it out tonight for a few minutes looking for any obvious issues, but not finding anything yet.

I had already purchased a new MSD replacement coil, so I installed it tonight for good measure...plus its red...(lol)

Keep in mind, the opti, plugs, wires map sensor, coil fuel pump and filter along with many other parts are within 3-5 thousand miles old and replacement parts have been good quality parts. It runs real strong, and has no issues other than what Im experiencing now.

Suggestions PLEASE!!

 

did you figure out if it was fuel or spark it was missing? maybe some starting fluid make it run for a second.

 

I would say its a spark issue. Fuel pump is a GM unit and just a few thousand miles old. The fuel pressure was good when I checked it.

I jumped the A&B terminals and have only one code. a code 16

I put a new coil in it last night but waited until this morning to start it. It fired up in a split second. I let it idle on my lift for a few minutes,shut it down and it fired right back up again.

Could the code 16 be a result of a weak or poor quality coil?

 

its usually the wire harness between the opti and the connection by the evap valve.