93 mustang charging problem

[tom2001gt]

I have a 93 mustang and the battery light came on yesterday so i checked and it only had around 12.5 volts running. I went out and got a new Alt and put it on and it was charging around 14.5. It was fine the first few times i drove it now the battery light comes on and off. I took it home put my meter on it and it was charging around 14 volts at idle then a few min later it will just drop down to 12volts then start working again.
Anyone have any suggestions?

 

[palma411]

I had the same problem on my 1988 GT, I installed a 130 amp 3G alternator on it and it took care of the problem. If I am not mistaken you should have the 2G alternator 65-75 amps on there with a regulater plug and a rectifier plug. The swap is quite simple if not you can upgrade the inside of your current alternator to about 100 amps or so.

 

[tom2001gt]

well the car is all stock It dont have Under drive pullies or anything so i dont know what is causing this problem.

 

[ebk06]

Fox bodies have underpowered alternators even when brand new. I'd say upgrade to a 3g and be done with it. Its also possible you got a faulty "new" alternator. It happens quite often.

 

[HISSIN50]

I'd also go get that new alt bench tested. Because the issue is intermittant, it might not act up while you're having it tested.

 

[tom2001gt]

I was thinking it might be a bad Alt, I got another mustang im gonna swap them today and see if the problem goes away.

 

[Stever89]

Wouldn't hurt to check all your connections too.

 

[tom2001gt]

Put the Alt from my other mustang in and its working fine now guess I just got a bad one.

 

[Kingflirt1]

i also switched to a 3g alternator with 200 amps. i have a mark 8 fan on it that sucks 30 amps itself. even with a stock alternator in a stock car still sucks when you turn your headlights on, fogs , heater or a/c. i noticed that when my car war stock.