My brothers 89 Mustang wouldnt start this morning so he went to jump it. He put the cables on right on his car but put them backwards on my car because the wires are the same color and the +/- symbols are on the back and he didnt look. My car is fine now but his starts up, the battery gauge is all the way down, and when he tries to drive it it gets really jerky and stalls out. Could crossing the wires have messed something up on his car? He was planning on getting a new battery anyways but do you guys think that would solve the problem?

thanks
chris

 

fried the regulator, time for new alt.

 

So he needs a new alternator? If so, would going with a higher amp alternator help the car charge better at lower rpm's? He has underdrive pulleys on it now and the alternaotr doesnt seem to charge the car at idle. Is any alternator especially good at that?

Thanks
Chris