c4 coupe problems
Thread Starter
Intermediate
Joined: Mar 2013
Posts: 38
Likes: 0
c4 coupe problems
first vette....love it 1986 cope doug nash 4+3....now could someone help me troubleshoot the ecm on this model..what are the warning signs of premature failure...here is the scenario.....cold start up is fine ....recently the cooling fan comes on way to early,with different cold temps.normally comes on around 228 degrees....ok now its sitting idleing and warming up and suddenly engine quits....now if the fan didnt come on prematurally i can re start the engine with no problem,but when i do it goes to high idle and the fan comes on. i am my no means mechanically gifted..and i am kind of afraid to drive the car anywhere thinking it may leave me stranded.....86,000 original miles and i really like this car a lot. also love this forum with all the good advice and helpful facts......tnx in advance...all thoughts on this prob will be greatly appriciated....jerry
Pro
Joined: May 2012
Posts: 519
Likes: 5
I am having a very simular problem with mine. All of a sudden the heater goes into auto with no touch from me. The AC Rad, fan comes on. Then it goes completely dead. Engine stops. I think it is reading low voltage forcing a shut down. Then after it resets it starts right up. I have driven it with no problems.
Drifting
Joined: Oct 2001
Posts: 1,770
Likes: 33
From: Cohasset MN
2017 Corvette of the Year Finalist
2016 C1 of Year Finalist
I have a '86 Coupe and have replaced the ECM. It was giving me start problems and running erratically. If you have a shop manual and a digital voltmeter you can troubleshoot the ECM and see if it is defective.
I was able to order a rebuilt one (with exchange) from Mid America for about $100. I didn't see it in their catalog lately but they should be available from one of the catalog houses.
I was able to order a rebuilt one (with exchange) from Mid America for about $100. I didn't see it in their catalog lately but they should be available from one of the catalog houses.
Pro
Joined: Aug 2001
Posts: 617
Likes: 14
From: Loudon, TN
Is there a check engine light warning showing? If so you need to pull the codes to determine where the problem is located. I strongly suggest you invest in the shop manual for your model vette. It has trouble shooting guides to help diagnose the problem. You can change the ECM and if that doesn't work, then what? Replace enough parts and you might get it to run properly but what if it is a bad connection or broken wire? New parts won't correct that. Before anyone here can provide any helpful information the SES code is necessary. No code, well that's where the manual and a mechanicaly experienced friend will come in handy. If you don't have the experience to trouble shoot the problem or have a mechanicaly inclined friend to help, take it to a reliable shop, you'll be dollars ahead and a lot less frustrated and angry plus you will be back on the road.
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