Looking to some GURU's for advice. I went to a car show yesterday about 40 miles from home. Car died 3 times while at road speed, did not run bad just shut off like I turned the ignition switch off. I pushed in the clutch and it started immediately and ran perfect. No driveability issue just shuts off. This is a pretty nice 85 GT, 4 spd fiero. well maintained. The trip there and back did this about 4 times each way?? Thoughts?? Thanks in Advance
If your GT still has the 2.8, a faulty ICM (the little module under the distributor cap) will cause instant shut off issues; and usually only when the car is at operating temps and the module is hot.
Usually with this component however, the car won't restart after it cuts out until the car cools off a bit (if it's going to restart, that is). Failing ICMs are a very common issue, especially with the chinese parts that the market is filled with these days. Next time your car stalls and if it doesn't restart, crank it and take note of your tachometer, if the RPM needle goes up a little when you crank it, the issue *usually* is the ICM.
I keep a spare in my Fiero because over the ~8 years I've had mine, I've went through three. An easy change with only a phillips screwdriver needed; easy side of the road fix. They tend to last about 3 years before failing.
------------------ "Discord" Red 1988 GT under restoration!
I had an 88 coupe that would do the same thing. It wouldn't restart unless the ignition was turned off, even for just a few seconds, then it would restart. Changed ECM's without result. I never found the problem, and neither did the subsequent owner.
But Shho13 probably has you on the right track for the V6. Even if it turns out not to be the ICM, you will have a spare, of which you should always have a spare with the V6. Some white or silver thermal heat sink compound, too. Not the clear stuff.
Failing ICMs are a very common issue... Next time your car stalls and if it doesn't restart, crank it and take note of your tachometer, if the RPM needle goes up a little when you crank it, the issue *usually* is the ICM.
Sorry, but I believe you have that backwards. A bad ICM will not move the tach needle while cranking.
...when you try to start the engine, does the tachometer do anything at all? If the ICM is working, the tach should twitch a little bit during cranking. There should also be spark at the plugs.
My experience with an ICM going bad is that the engine will run rough before it dies. Then after the ICM cools down, the engine will start again... but the ICM is now on borrowed time.
My 88 with 3.4 V6 Camaro engine does exactly what you describe. Took quite a while to find out what was happening. I changed the ICM but then it did it a few more times.
Finally found out that the problem is not the ICM but rather the two pin connector that connects the pick up coil in the distributor to the ICM. It is tin plated but there is steel associated with this as well. Our distributors are *NOT* sealed against moisture, so the connector pins oxidize and rust. Once the pins heat up, you can get an intermittent contact with the pick up coil. As someone else mentioned, you let it cool down and it starts working just fine.
The solution is to take the cap off the distributor and clean the contacts in the white connector. Just unplugging and reattaching is enough for a quick fix! Cleaning the connections and using dielectric grease to keep out moisture is enough to keep the connection working.
We were bringing the car back from Dayton back in 2014 and it started doing this right at the Texas state line. It started back up a couple of times, but eventually would just not keep going. Spent a day in Mt Pleasant,Texas waiting for my wife and daughter to bring the Tahoe and a trailer to fetch us from Austin. Thankfully we coasted a good 2 miles to the exit for Mt Pleasant!
Thanks for the responses, Just before this little trip I had changed ECM and put in a Echlin unit. I also carry a spare . I don't think it is the ECM because if the unit fails (overheats) the car will not start until it cools down. My car starts immediately and runs perfect. Just dies. I will check all the pin connectors as one member suggested. I have owned this GT for 21 years and never had this problem!! GRRRR!
My 88 Duke would restart immediately, too. Once I was in the middle of 5 interstate lanes in Atlanta traffic at 70 mph when it died. Clicked the ignition back 1 click so as not to lock the steering wheel, then back to start and it fired right up. I had to do that 5 or 6 times for the remaining 30 miles home.
I never got around to changing out the ignition module on the coil pack, but that could have been the problem. Something that's never considered is the actual ignition switch located underneath the dash on the steering column.
[This message has been edited by fierofool (edited 08-23-2021).]
I had a similar problem, it was caused by corrosion on the terminals on the junction block by the C500 connector. I cleaned up the ring terminals on the wires and installed a new junction block to fix the issue. Rodney has the junction blocks if that turns out to be your problem.
Clean/fix + wire above and All "grounds" bolted to engine and engine bay. Coat w/ Silicone or Brake Grease to stop future damage.
Even if isn't the root problem now... will be problem because of iffy "grounds" etc. After solving current problem... Do same for other grounds in the cabin and front of car. They often need cleaning/fixing too. See my Cave, Wire Service
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I second (or third?) the ICM being the problem. I've had the exact same problem a few times now and it has always been the ICM. Car runs great until it just suddenly dies.
I second (or third?) the ICM being the problem. I've had the exact same problem a few times now and it has always been the ICM. Car runs great until it just suddenly dies.
+1
Had this same issue on my first Fiero took a while to diagnose as I wasn't familiar with the platform back then. BVMotorsports helped me figure it out in Spinchat many years ago now~
