I have aquired an '88 5.0 Mustang today. I'm having a problem with the charging system. There is a brand new alternator and battery in the car, but it will not start. I can jump it and once I drive a couple miles it dies. If I put the lights on or any other load it dies. The person I got it from already put 2 alternators in it, one which is still in it now, both new and a new battery but still it dies. So I'm ruling out the alternator since it literally is brand new and the fact that it's the second one put in in the last weak. Any suggestions???

 

Go to autozone or advanced auto and they'll run a test on your alt. and battery and tell you if they are good or not. I had 3 bad alt. from advanced auto, and they were brandnew.
Could be a bad ground too. or a shorted wire

 

I'd just go up to Autozone but it won't make it. I'll just have to take the alternator off and take that too them so they can do a bench test or something. I checked grounds with a meter with a continuity test and they seem fine, but i'll go back through them all and clean them up. I hope it's that the alternator is just bad. I just have a feeling that 2 alternators bought new by the same person in the same week at the same store is just too much of a coincidence. But like you said, you had 3 that were bad, so maybe I'll have the same luck. Thanks for the help.

 

Sounds like there is a problem in the wiring possibly. Have you checked for power to the alt?

 

dude i had the same problem with my 87 vert i just bought, the motor is a 90. Same thing when i put the lights on or the top down it would rev up and down like crazy then die. The guy put a 3g alt in and never connected the two black wires with the orange stripe to the post on the back of the alt where the big wire is. Check that out might solve your prob did for me. i would have never figured it out if it was not for people on this site. Thanks again guys!!!!

 

I took the alt to Autozone and they tested it, it was fine. So at least that marked that off my list. So today after I got back from autozone and put the alt back on , I started cleaning all grounds and while I was taking off the selenoid, at least i think that's what it is, it's on the fender right next to the coil pack, anyways... I took the "selenoid" off and while I was looking at the mess of wires coming off of it and around it I see a small gauge wire that is not connected to anything, I look down and voila!! there's the other end of it, so I put in a new wire and jump it and it's perfect. I must of drove it close to 50 miles today with no problems. So after looking at everything and assuming some things, all it was ..was one single small gauge wire that was so old and brittle it just fell apart. I'm happy with the quick and helpful responces I've gotten in just the 2 days I've been a member here, thank you guys soo much and you will be seeing me more I'm sure, because I have alot of plans for this car and most likely will need help.