93 mustang charging problem


Founding Member
May 20, 2002
Delran N.J.
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?
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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.
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.
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.
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. :flag: