The last few days my 86 c4 seems to be possessed. Last week I needed to change my cooling fan. and in doing so I caused a host of problems. The MAF cable got caught in the drive belt and shorted out the MAF which I had to replace. Once I had that replaced I still had SES light and when I hooked up my scanner I had multiple error codes. MAF High, MAF Low, TPS low, EGR error, IAC error, and so on...

Well I set about fixing the varies troubles which included repairing the MAF wiring, replacing the IAC valve. Setting base idle, and TPS voltage and finally I was able to lose the SES light. Every thing was running fantastic. Plenty of power, good acceleration you name it. So to finish off the day I went to the car wash and wanted to clean the front section under the hood where the light wells are. Also the rack and pinion area. that was it for under the hood, I proceeded to wash the car and when I went to start it I got a SES light again. The idle was very rough and it felt like it was missing on 2 cylinders and had no power at all. I thought that maybe some stray water got into something and a good long run on the freeway would dry out the offending component.

Well it did not change anything. The idle was still rough, and it really lacked power, a lot of power. Fortunately I still had my scanner in the car so I hooked it up and got three errors. MAF High, TPS voltage low and a Knock Sensor error. So I disconnected the battery to clear all codes and restarted the car. NO SES light. but still a rough idle, no power and the same 3 errors I just mentioned. What the hell happened in the short amount of time from running great to running rotten.

I'm at my wits end here with this car and If I did not have so much invested in it I would set it on fire. So please, if anyone has something to offer here send it along as I'm desperate now.

Thanks everyone!

Tony

 

Some times its the simplest of things that cause a problem. I found the culprit here and thought I would pass on what I found for others that might be having similar problems.
So It turned out that two of my spark plug wires were baked and shorting out to the exhaust manifold. When I found them the insulation just crumbled off the cables. So there you have it. Watch how you have your wires routed. Installed a new set of Accell yellow spark plug cables and all is good again.

Tony

 

Yeah these cars are old now. Sometimes when you disturb things it’s easy to create new problems. I guess when you were cleaning under the bonnet you accidentally moved the spark plug leads and caused them to contact the exhaust manifold.

 

It would seem so Greg, Fix one problem create two more. I guess its all part of the joy of owning a Corvette!

Tony

 

I’m careful with mine these days. I treat it like an ancient mummy that might disintegrate in your hands. On the upside once you have replaced the parts they are good for another 30 years.