I've been chasing a problem with my son's '90 Camaro with the 3.1 V6, without success. I can fix any carburated motor but this electrnoic nightmare is a mystery.

It first started out that the car at times would not turn over, but power was evident to all accessories. The car would start randomly without having to fix anything. The occurance of starting and not starting became frequent enough that I figured the starter was going out. I replaced the starter and things were fine for about a week.

Now the problem has progressed to where the engine will shut down (electrically)and restart while driving, almost like turning the key on and off. When the intermittent shut down happens the check engine, air bag, and security lights flash just like when you first start the car. Often it will not restart and coast to stop. Then turning the key to start nothing happens. Wait 15 minutes and it starts right up again.

I let the car run in my driveway for 20 minutes and ran fine the whole time. I then drove around the block and the intermittant shut downs occurred.

How do I logically trouble shoot this?

 

Just an educated guess, but could your ignition switch be going out?

 

It's worth a shot, least expensive at this point. I did try adjusting it after I replaced the starter. Can the switch be intermittant?

 

ya. My s10 had a bad switch and occasionally the gauge cluster and HVAC system would go dead, and all the warning light come on, but the truck would still run. It got worse and eventaully the dash would never work (stil drove it a bit)

I pulled apart the switch after I replaced it and one of the contacts was severely discolored and melted.

a bad switch has a cascade effect. Increasing the resistance of the contact generated heat, which further damages the switch and increases resistance even more... Pretty soon everything melts.

 

I'll check it out tonight, thanks for the tip.

 

Hopefully that does it for you. If that's not it, I think you are going to be getting to know your multimeter much better.