QuestionI have a 69 383 Road Runner and its having a bit of a charging issue. When the car is first started the ammeter is on the charge side and I have about 14.5v at the battery & alternator. After driving for about 5-10 minutes, the ammeter sits about center with a 12.3 volts at the alternator and battery. I have replaced the alternator and voltage regulator with no change in results. Everything on the car ahs been restored to "stock" specs - no electronic ignition, etc. After driving for a while and trying to restart the car, the battery feels very weak, so there is a problem somewhere. Also, if I shut the car off and restart after it warms up, it still will not charge - it only charges when it is cold. What could be causing the drop in voltage after the car warms up?
Thanks in advance!
AnswerThe 14.5 is about right, but the 12.3 is quite low - so you are right, something is definitely wrong. There is no way to diagnose something like this without proper meters and adjustable loads, so my advice is to take the car to one of the auto parts stores that advertises free diagnosis of charging system problems. Of course they are hoping they will wind up selling you an alternator, regulator or battery, so be prepared for the sales pitch, but if you let them use their diagnostic equipment on it, they should be able to spot the problem. I don't know where you live, but at least out here in California, the folks at the Auto-Zone stores are pretty good at this. NAPA stores also offer this service, and they are usually pretty trustworthy.
Before you do that, though, double check the ground wire on your regulator - a poor ground connection can cause this sort of problem, although the variation with temperature seems to point to a problem with either the alternator or the regulator, check this first.
Dick
