Strange alternator issue
 

Hey all,

My car seems to have developed a weird alternator issue. To start with, the alternator was rebuilt last year. So far, it has been charging and running the car fine.

I've noticed that sometimes after a restart I will see surges in the head lights while idling, or when turning on/off indicators. I have had on occasion, the car momentarily dies while driving when a large load such as the AC switches on. If at a light, the car dies. On the freeway at 70, it is a quick surge and back to normal. Most of the time, I notice my stereo turn off and back on. IT is very voltage sensitive.

The issue is that this is a sporadic issue. I started up car this morning, drove to work. No issues. I'll check voltage at battery and it is usually running at 12.7 or so.

I'm going to pull alternator and take to a new shop. Any thoughts before I undertake another rebuild.

Jason

I would start by load testing the battery. Battery voltage while running should be around 14 volts.

Jason,

Thinking out loud a little bit. What you are describing sounds like a voltage regulator problem. The first thing I would do is to get a $10 voltmeter that plugs into the cigarette lighter and watch for spikes. Anything momentarily spiking up to say 17V would be an over-charging problem. Your symptom of the radio turning off is a hint. Some radios do that as a protection against over-charging.

Good idea to have the battery tested as gomezoneill suggested. You might find a problem there. If you are having lots of over-charging events with a conventional lead acid battery it is possible you can boil the battery and damage it. If you smell a strong sulphur "rotten eggs" odor that is a giveaway.

It is also possible with these older cars that you could have more than one issue. I have chased a bunch of electrical gremlins. Bad alternator, cracked fuse holder resulting in intermittent power loss, parasitic battery drains, bad grounds -- you name an electrical problem and I've had it. Point is, consider the possibility you have more than one issue. Only way to thoroughly fix it is to be very deliberate and systematic.

I'd start with the voltmeter and getting the battery tested. Next I'd check for parasitic drain. Clean and check all fuses/holders. Get some Deoxit D5 and emory paper to clean contacts. Check grounds.

CLEAN all the major power connections both neg and pos.
start at the battery. clean the one to the chassis
clean the one from the body to the tranny.

did you connect the ground strap from the alt to the engine

All great advice, especially making sure you have the Alt > Engine > Body ground straps (two, often braided) in good overall condition (replace by age, not appearance). To do this you would have to pull the alt. so in that case I'd have it bench-tested.

Test that battery as well - often low voltage from one or two bad cells plays with the regulator.

BTW, do you smell any sulfur in the cabin?

Thanks guys. I hadn't even thought about the cigarette lighter volt meter. I'll get one today.

The battery is a brand new Optima red top and is trickle charged on a Battery Tender between uses. FYI - issue is seen on different batteries. Stupid me left my glovebox door open for a week and killed a standard Autozone battery. I replaced it a few weeks back with the Red Top.

All connections were cleaned when I put the engine back in the car last summer. This issue actually popped up a few times last summer, but I ended up parking car for fall and not driving much. It mostly happened when turning on high beams but the issue went away when I put in the relay kit.

It really is hard to reproduce like so many electrical issues. I can start it and have no flickering lights. Then drive to store, restart again and have flickering lights. I'm starting to think it is the voltage regulator.

Jason

Innova makes a voltmeter that's about $10 you can get from Amazon. You can probably find it locally too. They're pretty common. Get that and then try to correlate what accessories are on with the battery voltage behavior. That might help give you a clue at what areas to focus on.