Driving down the road today had the exact same issue I did 2 weeks ago. The car had a loud shriek and then stopped charging and when I got home and turned the car off. It stayed running until I took the battery cable loose.

I have recently replaced the alternator, starter, ignition switch, cable from alternator to battery. It was working great, in the garage anyways. Then took it out for a drive after getting it some new shoes.

I made it 2 miles down the road, before it did what I listed at the beginning. It appears that issues with the wires that go to the starter. I spoke with someone and they mentioned unhooking that small connection on the starter and hooking up the trigger to remotely start it to bypass that cable to see if it would fail.

I had heard about heat soak as well, but don't know if that pertains to my problem or not. When it is working, does seem a little sluggish, so wondering if the exhaust is clogged up with critters. Seems to idle just fine and the temps don't appear to be getting really high.

 

A loud shriek and stopped charging sounds like a bad alternator or alternator bearing, that shouldn't happen on a new or rebuilt alternator. You might want to pull the alternator off and have it bench checked. Be sure to check all of the idler pulleys as well. If the engine continues to run with the key off I would say you have a hot wire shorted to the ignition wire side. I would do a close inspection on the wiring, it does sound like it could be a critter issue. The heat soak issue is more prevalent in warmer weather the starter gets over heated. Heat soak was common on starters in the 70s when gm engineers figured out that the starter solenoids had a strong return spring and when the spring got heated it got stronger and the 12 volt solenoid could not over come the added spring pressure and then the starter would not engage, (there was nothing no click or anything). Their fix was a shorter spring in the solenoid and insulation from the exhaust manifold. Most new replacement starters today have the newer spring and don't have that issue. You could have a restricted catalytic converter that could give it that corked up filling. Critters could have packed some insulation in there, (maybe some wiring)? Probably not..

 

Thanks so much for your reply and great information.

When you say the hot wire to the ignition side, you mean the small connection on the starter? That seems to be where my crappy wiring is. I tried to fix it with a jumper but I'm sure it didn't work so well.

When i replaced the starter before, it wouldn't even try to start anymore until I fixed that wire.

 

On your starter I don't believe there are any wires going to the ignition. The battery cable could have two smaller wires on the starter on the same post feeding the 12 volt system (I'm not sure about the 86 models) they could be hooked to the battery terminal and not the starter. The small terminal on the starter closest to the engine block is the solenoid, purple wire that goes to the ignition switch. There shouldn't be any wires on the starter that goes to the ignition system that could short and keep the car running. The small terminals on the solenoid is there but never used anymore. One batt wire and maybe two smaller 12v wires and the purple wire for starter engagement, If it didn't start before it must have something to do with the wiring or starter itself.