I just replaced the alternator on my brothers '66 Pontiac Catalina 389 and when we first fire it up the amperage needle is just a little below the middle mark, if we rev the engine it will go off the scale then slowly come down to a little higher than where it should be charging also it(the alternator) is making a whining noise. The alternator is an internally regulated kind and the car at some point had an external regulator but I thought it had been disabled(not 100% sure though). Could it be that the other regulator is still hooked up and causing this problem or is it a bad alternator or is it something I haven't thought of?o No:
Your battery is likely not fully charged. Assuming it is OK, and does not have a shorted cell, I would put it on a slow charge for a while and see if the problem goes away..........sounds to me like the alt is just doing it's job..........those whine when they are under a load.:bglasses:
I had taken it to advanced auto the day that I switched it out to have them check the condition of the battery and they said it was good. Could the equipment they use be off?
if they did not perform a load test on the battery , then there is really no way to know the status of the battery .
Betteries are simple devices. When fully charged, they draw minimal amperage. When discharged, they draw more dependent on their state of charge. Try this: connect a battery charger to the battery. If the charger also shows current into it, it is either discharged or internally shorted. If internally shorted, the current will not drop as the battery will not recharge. If little current flows, the alternator may be incorrectly connected. The alternator SHOULD wail when charging heavily. This unit uses resistance to ground to control charging rate. If something is holding full ground on the unit, it will charge fully until it destroys something. I will answer questions on this subject; you might try looking elsewhere on this forum where I indicated how to connect a 10SI or 12SI alternator in place of an externally regulated unit. Ray
