I have a 94 Z28. It runs great when it runs, but as I cruise down the highway it will do a cough/sputter every once in awhile. Two times now it has quit alltogether; I will be driving and it will quit then run quit then run until I come to a stop, it acts like and ignition problem. It has a MSD cap, rotor, and coil. I swapped the stock coil on one time when the car quit along the side of the road and that did not fix it. I also put a new fuel filter on and have a gauge on it and it keeps good pressure, so I dont think its a fuel problem. Once it dies along the side of the road I can crank and crank and it never fires, but if I let it sit for a couple hours and cool down it will start right up and run great until it does it the next time. Has anyone had similar problems and figured it out? ignition module possibly? Please help, Thanks

 

Have you tried a new ignition module?

 

yea my car was doing the same thing man an my problem was what petes talking about. if the ignition control module goes bad once it gets hot it starts messing with the firing an will want to shut your car off. i changed mine and it hasent had a problem yet.

 

I had a similar problem and it turned out to be my coil, but where you have changed that I would wonde about the icm. How many miles are on the MSD opti?

 

he said it was a msd cap and rotor so im thinking its just a rebuilt opti

 

No, I have not tried a new ignition module yet. The previous owner put the MSD coil cap and rotor on probably about 15-20K miles ago. The car has run fine for the last 3 or 4 months that I've had it and it just started doing this a couple weeks ago. I'm most suspicous of the ignition module and that is what I will pursue next. Another thoery Ive heard of if the oil pressure sender is faulty and as soon as the engine oil warms up and thins down and drops a little in oil pressure, that it disables the fuel injectors. I dont know if the 94 Z28 has that function or not, but I think I will try the ignition module next.

 

The 4th gen cars no longer use the oil pressure switch to cut off the fuel pump.

 

Ok guys, I ran the car for awhile and got it good and warm until it finally did its cutting out and dying thing. I swapped in the new ignition control module, and it continued to do the same thing, just running on all 8, then losing everything, then maybe pick up again, then cut out all the way again, until it completly dies. I unpluged a fuel injecor and put a noid light on, and when the car cuts out, it is losing its fuel injector signal. I've got a gauge on it and the fuel pressure is fine and stays up all the time. So long story short, i don't have an ignition problem, but when the car quits, Im losing my fuel injector signal. Any more ideas?

Mike

 

Ive been driving the car on short trips to work where is does not warm up and quit on me. The other day after work was over and the car had been sitting there all day, I went to start it and it would just crank and crank and not fire a lick. The next morning it started right up. In an earlier post, the ICM was mentioned, what does ICM stand for, Im not familiar with what it is? Im suspicous of the ECM; I hooked up a scanner to it, and when the car warms up and starts coughing and dying, all of they inputs to the ECM go wild, its not just one individual input. So, I think its got a bad connection somewhere, or just a bad ECM maybe. Anyone had and expierences with ECM's going bad?

 

Ignition Control Module (ICM).