1992 Corvette Electronic Problems

[Dave215]

My 1992 LT1 Coupe has developed electronic problems. I thought I posted this subject before, but cannot find it anyplace within the site. Here it goes again.
At ambient temperatures above 60 degress F. the following occurs:
1. There is a surge felt in the rear end.
2. The engine idle RPM goes to 1500-2000 RPM.
3. The service engine soon light illuminates.
4. The service ASR light illuminates.
5. The digital speedometer display goes to zero.
6. The air conditioning goes to heat.
7. The engine RPM will occasionally fluctuate violently and be considerably unstable. There
is no power when attempting to accelerate and
all one can do is allow the engine idle RPM to move the vehicle along.
8. The engine stalls when the car is stopped in traffic. It will restart normally but the symtoms reappear.
9. Occasionally while driving, the symtoms disappear for a time then reappear and then may disappear again. The warmer the ambient temperature is the longer the symtoms last.
10. At temperatures above 75 degrees F. the symtoms appear and do not disappear at all.

At ambient temperatures below 55 degrees F. items 1, 2,7 and 8 occur.

At ambient temperatures below 45 degrees F. the car operates perfectly with no symtoms.

The dealer could not repeat the symtoms and indicated the problem was in the body control module. They said that they would need the car for 2 days to dismantle the dash and console to locate the BCM and do analyticals to isolate the cause. There would be no guarantee. before I head down that road, I would like to attempt the repair myself as I just know that the dealer tech will never reassemble the dash and console correctly to look as if it had never been touched. I would like to know if there is anyone out there who knows what the cause of the problem is and what corrective action to take. Also, if anyone knows a quality repair shop in the Stratford, Connecticut area, please advise. Please respond to my e-mail address which is DaveSuhy@SNET.net.

 

[c4c5specialist]

HI there,
Well, I am in Milford, if that helps.
Sounds like you are having a communications break down. HOwever, I think that you might have more than one problem here.
With all the lights going on, I think you may have a defective CCM, however, without conclusive codes, or results, accurate diagnosis is key to what could happen.
Personally, I would wait until one problem occurs, then bring it directly to your mechanic, do not shut the car down, and let them scan the system.
I know it may be hard to get it there, but time unfortunately is what it will take to work this out.
I wish you the best, c4c5

 

[vigman]

Arrrgh!

These kind of problems are the hardest to find. I would first verify all the engine / frame ground points to make sure that those are not the problems. Bad grounds are a source of many evils that are intermittant in nature. Has there been any major service done on the car recently ( or to your knowledge. if you just got thre car)

I have found alot of bad ground points for the engine to frame connection when the clutch / tranny
was serviced and the mechanic didnt put the ground lug on the right bolt and strecthed the lug to make it, not taking into consideration when the engine runs ( driving ) that it flexes.. and pulls the wires out of the lugs.

Also check the ground point on the top of the frame rail under the battery.. these get very corroded. And I dont mean just tighten it.. take it apart clean it, and put it back together.

Short of all that... does the car leak? does water get under the dash...or hood?

Keep us posted!
Mike