5

I have a '91 Ford Sierra Saphire 2.0 OHC (pinto). Have been struggling with having no charge for weeks now. I've tried two different alternators, had one of them completely rebuilt by a professional, so alternator is not faulty.

Every time it comes down to the voltage regulator breaking. If I replace regulator, alternator charges for like another 5 miles, then voltage regulator dies again. (I've already repalced it 3-4 times, while trying, I pay 10$ for every possible solution :/ ).

I've double checked every single connection (alternator B+ -> battery, alternator D+ -> dash, engine -> chassis, battery negative -> chassis, etc.), I have solid Earth everywhere I need to have (at least according to my multi-meter).

Haven't had the chance to try another battery. Can a bad battery in any way cause serial voltage regulator faults? If not what else can?

  • Does the battery have enough capacity to start the car? – Paul Jan 8 '15 at 20:55
  • Initially yes(if I charge it with a charger), then obviously without the alternator charging it discharges, and eventually it won't start the car. – galingong Jan 8 '15 at 21:07
  • Have you tried disconnecting the battery from the car, charging the battery on a smart charger for 24 hours, then leaving it off of a charger for 24 hours, then check the voltage? Or at least bringing it to an auto parts store and let them test the battery with a tester? – Paul Jan 8 '15 at 21:21
  • Actually I haven't. My first thought was borrowing a known working one and try the thing with that. As far as I know a bad battery does not necessarily leak voltage, nevertheless I should've already tried it. – galingong Jan 8 '15 at 21:50
  • If the battery holds a charge, then for certain it doesn't have a short. If it doesn't have a short, then it is unlikely the electrical problems you are having are caused by the battery. Even if it does have a short, it is a near impossibility that it is causing the problems you are having. – Paul Jan 8 '15 at 21:53
1

From a theory perspective, I would say it is nearly impossible that a bad battery, all by itself, can cause an alternator to fail. The only condition I can even think of would be if the battery developed a short, but even for that to cause the alternator to fail, there would have to be some other problem in the system, such as a bypassed fuse or something of that nature.

  • You were correct, the battery is fine. I can't indentify the problem even at this point, when everything is working fine. I replaced a bunch of cables, sanded every connector and ground point, alternator was known to be working. The only advice I can give to people with similar problems is to tear the whole thing down, clean up everything possibly related and reassemble. – galingong Mar 8 '15 at 17:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.