94c4er

I am having intermittent missing on my 1994, changed Opti, Plug Wires, ICM, Opti Harness, fuel injectors, fuel pump, etc. Battery and alt were changed but not because of these problems. Runs fine sometimes and then starts missing above 2K. Everything now is pointing to a possible bad ground or PCM. I can find the ground locations for a C5 but not C4. Can anyone tell me where all the grounds are so I can check and clean them???

Once I figure out the problem, I will post the fix.

THANKS!!

leesvet

There is a ground on or near every electrical system on the car...everywhere.

BUT, the most interesting bunch are on the block or bellhousing bolt near the oil filter. These include the ecm, interior, most engine sensors, and other misc display and control systems. Not easy to access but critic to have in good condition.

Grizeg

thought you were going to post a solution.........

Cliff Harris

Here's a link to the ground locations on an '86. I doubt that many of them moved over the years:

http://home.earthlink.net/~cliff_har...s/grounds.html

I would suspect that your problem is more likely to be either a corroded contact in one the ignition related connectors or your ICM does not have THERMAL grease under it. Some people use dielectric grease by mistake, which will NOT work and cause the engine to cut out when the ICM gets hot. Another possible cause is a loose spark plug wire connector at the plug.

hmr868991

A question. I have an 89 corvette the radio is suddenly having a whistling sound and the climate control reading becomes distorted. Would a second battery ground help

ctmccloskey

There are numerous grounds on the C4's that can cause some real problems if left ignored. The battery connections would be the very first connections. How old is the battery? Then you can check the ground of the engine and other components by using a multi-meter. There was one spot on my ground connections where I found significant corrosion. It was near the center of the dash and had a layer of rust on the base metal that it was attached to. I cleaned the connectors and greased them and reassembled them. At one point I was not able to get 12 dc on either side of a good fuse on my 1988 fuse block. the fuses had corrosion on them. I replaced the fuses and cleaned the fuse block connectors with a points file. You will find corrosion on the aluminum but on aluminum fuses?

Check the battery cables that connect at the starter, due to the heating and cooling they can break loose sometimes. That is a place that gets overlooked frequently.

Most of my problems were because even though I had 12.5 at the battery the battery voltages across the car were terrible. There were spots where the voltage to the radio was less than 11 volts, most of my dash had nothing above 11 volts on the positive connections. It was a primary connection for the entire car's interior and some of the engine controls. Under and slightly behind the battery on my 1988 Coupe is a stud mounted on the frame that has a battery RED wire going to the battery connection from the stud. The stud on my car was disgusting and covered in corrosion. This is the spot where seven fusible links get their source of Battery Positive and is critical to your car running properly inside and out. After fixing that one place my car started acting like normal and I had full battery voltage at the post and at the radio and most everything else. To clean the post you disassemble the parts and simply wire brush or sandpaper them till you get a clean contact surface and then I grease them and re-assemble them and tighten the nut and cover the post with a vacuum cap to keep the corrosion at bay.

I have noticed that there are several ground straps on these Corvettes, the one that connects the exhaust to the power antenna to the frame woke up my power antenna and now that is working properly. I would look at your Factory Service Manual as they show the places where the grounds are made for the car.
I hope that this helps you a bit, Good luck!

Kamado

Where can I find a diagram. That shows all the grounds for a 96 c4. I feel I missed one. I have replaced the fuel pump (it needed it) it ran for a few months no issues. Then it started dying. Checked the vats did a bypass, and used the right measurements. Car ran great for a while then it started dying again. Checked the grounds I could find. Some where corroded, cleaned and car still wouldn't start. I replaced ignition control module, i replaced the spark plugs, spark plug wires. Checked fuses they are good. Car still won't start. Then I replaced the optispark. It ran great for a couple of weeks. Parked it. Went to drive it and nothing. I've also replaced the battery. Nothing. I recently replaced the ignition switch on the colum. Nothing........ it had to be a ground I missed somewhere or the ecm. I want to find to find if the grounds and check them. Just annoying that a part gets replaced and it runs for a while just to die. Seriously going to set this damn car in fire.

Toy96CE

I just had a crank/no start on my 96 ... Here's a link to what fixed mine . Something to look at.

https://www.corvetteforum.com/forums...th-electr.html

Kamado

Thanks for the link. Ill def check those out. I was think it may have something to do with the wiring harness coming form the fuse box, or the wires ( I really hope its not the wires). Since I've checked off all the possibilities, but it makes since, if all of the starting components are new, its getting more electrical push than it was use to. Causing issues with the harnesses at the fuse box or connectors. I wouldn't be surprised if they were crispy. Ill update with pics if that is the issues. Ill also post what I did to fix mine when I finish finding the electrical gremlin and crucifying it lol I've noticed pple post issue they get it fixed but never tell us what they did lol.