jrobida999

I'm fresh on this forum and I need some help.

I recently bought a '79 Mustang with a 302 and it definitely has some issues.

I'm going to do a full rebuild on the car, but right now I just need to get it to run.

I put in a new alternator, the battery has been tested and charged and re-charged and is good, the voltage regulator also has been tested and is good.

It will start and run after I charge the battery and when also when I connect jumper cables to another car, but once the battery dies it's done.

It seems to me as if it's a problem with the wiring between the alternator and the battery, but I've inspected the wiring and it all appears fine.

Has anyone else had this problem? And if so how do I fix it. I checked the local junk yards and none of them seem to have any mustangs that are intact enough to be able to use the parts off of them, and I haven't been able to find any kind of rewiring or electrical diagrams for the alternator/battery. And I haven't been able to find any new wiring harnesses or assemblies for sale. Do I just not know the right term or what?

All comments and suggestions greatly appreciated!!!
Thanks
Jake

mjr46

you need to make sure the connections are on the alt in the right place and have a load test performed with alt on car

jrobida999

I double checked at the napa nearby and the guy told me i did indeed get them on right. We did a load test and the voltage started at about 9.8 and lost about a hundredth every 5-10 mins. It was a very slow loss.

mjr46

hmmm I don't know how well I'd trust the napa guy??,.....but if it is anything like my 85 with the external voltage regulator.. on the back of the alt there is a black push on prong and an orange one the black goes to the G mark = ground and the S to orange = Stator/ field connection and of course the charge wire.......it sounds as if the alt is not being fielded to charge.... you'll need to trace that circuit with a wiring diagram

Joel5.0

jrobida999

you might be right about the napa guy but he was a tech in their service center. Where would i find a wiring diagram and also one other thing. If I'm right, the wiring to the back of the alt has 4 wires, not 3. and one of those is like an L shaped black piece of rubber with a bracket on it that i put on the last nut on the alt. but then we found that the wiring harness those wires lead to was all melted out so we cut it out and spliced the lines. also, it appears as though when we try to jump start the car it is melting the sheath on the jumper cable. would that be something because of the jumper cable or something with my car?