Rhensonsr

I am looking at buying this 86 C4 with 120k. If the alternator is disconnected, it starts and runs great... But the battery will eventually run down. When it is running, and plug in the alternator, it suddenly dies. Any suggestion?

lbzraptor

Does it just die or does it pull the idle down till it dies?

Sid.123

Sounds like the alternator has an internal short or could be when 12 v is applied to the alternator it causes some kind of internal fault causing it to lock up, stalling the engine.
you could try plugging it in without the belt on to see if you get the same result

bac22

Remove alternator and have tested.

Purple92

A properly functioning alternator sucks up about 2 - 3 HP when charging at full rated output. That kind of load shouldn't cause the engine to stall. If it was a bad bearing - disconnecting the plug wouldn't matter. Chances are that there is some kind of electrical issue with the alternator - meaning that it will need to be rebuilt or replaced.

383vett

Buy the car for $1000 below the norm due to the problem and fix it with a $100 alternator.

Rhensonsr

Thanks for all of the replies. I decided to buy a 1984 instead.