Hey guys. Non-thirdgen but deffinitely chevy tech related. My brother has an '83 Impala. He's having some issues. Completely randomly, his car will power down and die while driving as if the alternator has gone and the car is using the last available power left in the battery. (Headlights dim.. hesitation above 50 MPH..etc).

So he takes the battery and charges it up... holds a charge fine, puts it in the car. starts right up. no problem.

Tests the alternator... fine. no problem.

Car will run and drive for an unspecified amount of time... it is not as if it dies when it uses the power the battery has stored, it's completely random.

What do you guys think? The only other variable is he has a pimped out stereo system that's connnected directly to the battery. This has been going on for abotu a week now, so it's fairly consistant, but he hasn't had it happen enough to really narrow down the cause.

Any help would be hot...

 

Well, try it out without the stereo system for a little while and see if it does it. SOme powerful stereo systems can drain a battery. I bet if you turn up the bass and have your car at an idle, you can watch your volts in your cluster go down then back up every time the bass hits. Either get a better altenator, or think about runnin a two battery system. Did the car do this before the system????

 

Nope, this is post-system. But it didn't do it immediately after it was installed... about a week and a half after.

Right now he's driving it with the amp & subz turned off to see what happens.

With a 2-battery system, aren't 2 alternators also neccessary? Do you think a heavy duty battery would do the trick?

 

If the alternator output gets intermittent as you describe, you might want to take a close look at the brushes and slip rings. The brushes could be at the very end of their travel and periodically not making contact. A new set is about two bucks.

 

Ok... discovered today that the alternator is putting out about 25-60 amps out. He was told he should grab a 110 amp alternator... but that's about 100-150 bux. Could the brushes & slip rings still be the problem?

thanks