Charging Problem Help

[Beinhower 95 TA]

Hello all,

I have a 95 Trans Am that is having a charging problem. Here is what happens. When I start the car and the engine is cold, I get about 14-15 volts. Once I start driving, when I push in the clutch and come to a stop, I am only indicating about 10 volts, and durring normal driving I'm barely above 13. I didn't realize the problem until one night when I had to run all the fog lights (including the rear, I live in England) and had the HVAC fan at max. When I got home, the car stalled and died when I pulled into the driveway. I've had the battery checked and charged and all was good, and I have also put a 200 amp alternator on it. I do have a smaller underdrive pulley, but I have had that for 2 years and never had this problem. At night my lights dim big time when I have to stop. I have a car alarm with an internal battery that I thought might be the problem but don't know. I thought about pulling non-critical fuses and starting the car to see if I can isolate the faulty system. Any help in the matter would be greatly appreciated.

Thank you,
Jesse

[raroZ28]

Sounds like a weak alternator. Is it new? Probably a remanufactured unit from a store, if it is. Those are not always that great. I would pull it and have it checked. They give you lifetimes on those for a good reason. If autozone didn't guarantee everything for life, I would never buy them, I'd just get it from the dealer and pay the extra cash.

Good luck with it.

[Beinhower 95 TA]

It's a brand new alternator. I thought that was the original problem so I replaced it. I can't imagine my old and new alternator would have the same problem.

[raroZ28]

It's a brand new alternator. I thought that was the original problem so I replaced it. I can't imagine my old and new alternator would have the same problem.

Me either... If you replaced it a few months ago, and the symptoms came back now, then I would be suspicious, but if you just replaced it then it's probably not that.

Joe is awesome with electrical on these cars. Hopefully he can help.

In the meantime, check out this site, if you haven't already. Shoebox

[Jeff_in_Atl]

This is my "poor mans" load test. Crank the car without anything on then disconnect the battery. Then rev it to ~1500 RPMs. Then start turning on things. Turn on the A/C, slowly turn up the fan. Then the lights then high beams then rear defroster. If the engine starts missing or dies at any time during then the alternator or regulator is bad.