1991 Coupe Ignition
 

Hi all, I seem to be having an intermittent enging starting problem brewing with my C4. At times, after driving it and turning it off, I go to crank it a few minutes afterwards and I get nothing from the starter. No click, no spin, nothing. No indication that the fuel pump is coming on either. However, the dash lights light up as they normally do when the key is turned to crank position. I'm pretty sure it's not the VATs. This normally happens with one or 2 turns of the key and then the car starts on the subsequent try. Tonight this happened and it took several tries and about 30 minutes before the car cranked and it has been cranking fine ever since

Any ideas on this? I would think I would hear a click or something if it were the starter? Could it be that ignition switch that sits in the center console that engages with the gear shifter going out?

If this only happens when the motor is warm I would lean towards the starter and/or solenoid. But consider the key is just the beginning, clean the pellet/resister of the key. Then you have Passkey security. (is the security light on when the key is turned to on?) After Passkey comes the CCM, the starter relay, the starter. If you don't hear the fuel pump start, then it's most likely Passkey or that harness between the key and the CCM. The console switch I assume is the neutral safety switch and yes it's there to stop the engine from starting while the trans is in gear. A factory service manual has the troubleshooting
procedures you need. I may be telling you something you already know but you didn't let on.

Yep, a lot of that I do know. You are right it only happens after the car is warm and has been ran for a bit. I'm leaning toward the starter. I think I'll just go ahead a swap it out for now and see if that gets rid of the problem.

Should be able to test the voltages going to the starter to verify they are switching when the key is turned as well. Might save you some heart ache if you find no voltage going to the starter to begin with.

Most likely the starter solenoid contacts are worn/burnt. Happened to mine.

My 1991 would occasionally do the same thing. Hooking it up to a set of jumper cables would start it. The battery was fine and tested as good. I installed a new battery and it didn't change things. I checked voltage when it was running and it is charging. Ultimately I believe it's my starter disable relay from the VATS system. I tried to remove it from the panel behind the instrument cluster and couldn't get it loose (gave up on standing on my head that day). Since then I've replaced the engine and I've been busy with other things.

If you can get under the car and hook a 12v light bulb to the trigger lead on the starter (and ground the other side) and duplicate the problem, if the light is on...it's the starter. If the light doesn't light, it's likely in the key switch or the relay.

fuel pump relay
 

Driving my 1996 and my 1985 Corvettes I always turn the key to only the "on" position and listen for the fuel pump relays which only activate the fuel pump for about 2 seconds and click off. I don't try to start my Corvettes until the relays click off. They always start immediately using this procedure. If I would not hear a relay click off after I turn the key to the on position that would indicate to me the relay is bad or it is not getting electrical power from turning to the on position in using the ignition switch.

I had a similar problem with my '87. It turned out to be the starter inhibit relay. Drove me crazy for a couple months.

I have a nasty oil leak that is leaking oil on the starter; I'm guessing this may be the problem.

You have probly narrowed down your cause and problem. Oil plays hell with the solenoid, dirtying up contacts, shorting out wiring, all kinds of issues. Try the new starter but until you fix the oil leak the problem will persist. Warm starting issues also point to the solenoid at the end of its usefulness.

Finally got around to figuring out this intermittent engine starting problem with my C4 about a month ago; Seems the problem was the ignition switch that mounts under the dash on top of the steering column was giving out.

That is the same procedure I have always used for my 85 and it starts immediately as well.