barta5088

I sold my 06 gt stang to a friend. Has 59k miles, c&l race intake, PA performance 200 amp alternator, brand new battery, charge motion delete plates, tune from BAMA and a few other things. For some reason the battery indicator on the dash keeps going up and down and will eventually the headlights will start flickering on and off along with the dash lights. The alternator and battery have been tested, alternator is at 14 amps and the battery is brand new. Checked all connections to make sure they are not loose or burnt in any way. The alternator cable was upgraded to the larger cable to handle the larger alternator as well. Made sure the correct tune is on the car as well. When this happened the next morning the car was completely dead. Had the battery recharged and would last about 50 miles before the battery indicator started to fluctuate again. I have no idea what is going on. Does anyone know or have any suggestions.

Dino Dino Bambino

Sounds like there's a bad voltage regulator inside the alternator.

barta5088

can a new regulator be purchased or is the only way to fix it is getting a new alternator. btw autozone checked the alternator and said it was fine.? Any other way to test it?

Chromeshadow

Did autozone use their "off the car"tester or test it on your car? I think their tester tests at one preset load, not all the conditions that it sees in your car. I'd test it in the car, measure the voltage at the alternator terminals and the current with a DC clamp, while changing the load by turning on lights, heater fan, AC, wipers, radio, and rolling the windows up and down.
I'd repeat the test with the meter leads directly on the battery posts. If the voltage fluxiuations are higher at the alternator than the battery, I would replace the alternator. If the fluxiuations are larger at the battery than the alternator, I'd try another battery, you may have an intermittent short in the battery. Btw,if your voltage fluxiuations are 2v, probably the battery.

JCON

Could easily be the voltage regulator. Unfortunately, while every one recommends PA alternators, they don't seem to be any more reliable than AutoZone brands. Why did you go to a 200A alt? Is there a stereo system in the car with amplifiers?

Dino Dino Bambino

Yes, you can get an alternator repair kit from American Muscle which includes a new regulator. Don't be surprised if the regulator has the letters CN stamped on it which would mean it was Made in China.
I replaced the alternator on my car a couple of months ago with a remanufactured Motorcraft unit but I also replaced the regulator in my old alternator to make it a functional spare.

barta5088

I choose to get the bigger alternator because I planned on upgrading the stereo. I ended up selling the car to a good friend and he has no "car" skills. So I'm trying to help out in figuring out what is wrong with it. I've posted this problem in a couple other places and have got probably a dozen reasons of what is wrong. I'm relaying the messages to him. I do appreciate everyone's feedback.

barta5088

so his battery died again and autozone gave him a new battery and ran the test on the alternator again and this time it was only putting our 10.6 volts. He just got one from there and installed a cheap one smh. I am getting the 200amp paperformance alternator back. Any recommendations on what to replace on it to make it functional or new again. TIA

Dino Dino Bambino

This:

http://www.americanmuscle.com/paperf...epair-kit.html

SCCAGT

A regulator can, but rarely, work then not work. Unless you feel confident tearing apart the alternator to install this new regulator that someone put up, the only replacement is to do the whole thing. Regulators are built into the alternators. And its a whole lot less time consuming to just drop in a new alternator on these cars. Yeah, its more money than the rebuild kit. But, IMO, if you have to ask this on a bunch of forums, you should probably be a bit cautious about trying to rebuild an alternator yourself.

If the alternator is working correctly at the time of testing, its not going to see anything wrong. That along with the sometimes questionable capabilities of personnel at a parts store would have me say, take it to a shop and have them do the test. Some wont charge for it, so ask first how much if they do, and they will test it correctly at idle and under loads. If they do charge, it should be very minimal.

A good battery should test at 12.4-12.8 volts. A good alternator will stay around 14.0 +/-.
That 10.6 reading is either a bad cell in the battery or a battery that has been drained from lack of charging by the alternator. Since he already bought an alternator (if I understood correctly) they should give him another under warranty. Most parts store alternators have at least a 1 yr warranty. Others have lifetime warranties. It is completely possible that a bad one was sold new. I have had plenty of bad parts right out of the box at my shop. Alternators and starters have the highest failure rate.