I think my voltage regulator just went, because i can start the car fine, but it lacks power and sometimes backfires, but when i connect jumper cables from another car, it runs perfect, i wanted to know if the voltage regulator is internal on the 78, because i had my battery and alternator tested, and they are both fine....any thoughts?

I think my voltage regulator just went, because i can start the car fine, but it lacks power and sometimes backfires, but when i connect jumper cables from another car, it runs perfect, i wanted to know if the voltage regulator is internal on the 78, because i had my battery and alternator tested, and they are both fine....any thoughts?

The VR is definately internal on a '78. Low voltage will certainly mess with the FI and cause things to act wierd. But if you had the alternator tested, didn't they test the voltage too?

Yea, the voltage was within specification...im going to check the wiring from the alternator to the battery, its just hard to get at.

Well, i think i figured it out, the alternator charges fine over 2000-2500 Rpm's, but under that it wont produce a charge, so it needs a rebuild or a replacement. Any last thoughts before i spend $100 for one?