Alternator problem (3G).

[Dbeck002]

Ok guys i really need some help with this. I have a lot of info on what my problem is but i dont know how to solve it.

i have a 3G style alternator in my 91 fox. installed it over 3 months ago and ran perfectly with it.

i also have a battery relocation so a large 2AWG cable is running from the alt + to the batt + (cable goes under the car). just recently my electric radiator fan relay fried on me so i replaced it with a huge ass 400 amp solenoid that will do a great job. i dont know if the relay has anything to do with the problem so..

problem: when car is off and key is out, voltmeter detects 12v when lead is touching the alt + terminal and black lead grounded. is this normal? because my alternator got so hot i couldnt touch it, this was while my car was off for hours, i understand that current is passing through the alt. wtf is going on though, i always thought that the alt + should be attached to the batt +.

if youre wondering, i do have a killswitch in the bumper. i checked over the wiring 100 times and its been the same for 3 months.

alt cable, and batt + cable go to one killswitch terminal. accessories and starter cable go to other killswitch terminal. it shuts off the car with no problem and its been rigged this way for a while. why is my alt being fried???!!!!! help meh..

 

[Dbeck002]

by the way i left the cable unplugged from the alt so the alt wouldnt fry. i only just started happening today, i had the battery pulled the whole time so when i put in a NEW battery (needed a new one) it started to happen. Do you guys think that this battery is not made for a 5.0? i heard somewhere that if you get the wrong battery (two digit code i think) then it will hurt your car. not sure...

 

[Daggar]

The diode in the voltage regulator is bad. You can replace the alternator or you can try and get a replacement regulator and do the swap yourself. What's happening is that the battery is trying to "motor" the alternator when the engine is off. If it's a stock 3G then getting a regulator shouldn't be too difficult. Give a couple local parts stores a call and see what they can do for you. If all else fails, order one online.

 

[Dbeck002]

awesome dude, thanks for the reply. i will try to get a diode but i hope NAPA carries them, should i ask for a 94-95 mustang alt diode or 96+? not sure what to ask for, they wont know what 3G is

 

[Daggar]

You need to ask for an alternator voltage regulator for the 3G alternator. If they want the year and make tell them the alt came out of a 96 or something.

 

[Dbeck002]

Ok ive just been to 3 parts stores and none of them knew wtf i was talking about. i told them the alt still works but it needs a new diode, they all said they dont carry them. i dont know where to get one.

 

[Daggar]

http://www.pa-performance.com/displ...qPartNO@,rqDesc@,rqOrder@,backNum@1,nextNum@2

 

[Daggar]

Did the know-nothing yahoos at the parts store at LEAST offer to test the alternator for you?

 

[Dbeck002]

i asked one of the guys to test my alt and he said they cant test that year mustang, the alt has to be in the car. IF IT WAS IN THE CAR AND RUNNING IT WOULDNT NEED TO BE TESTED RIGHT??? ROFL DUMBF-CKS


people these days,

by the way thanks for the link man you saved me...