Auto Parts Store Rebuilt Alternator

[67GTX440]

My battery kept dying. I had replaced the battery as it was under warranty. Sears said it tested fine, but the case was slightly swollen, so they gave me a new one. I had my old alternator tested at Advance Auto Parts and they said it was bad. I bought a round back 60 AMP replacement as car is basically stock with no big power draws added. I installed it and battery died again. I took the new alternator back to Advance and it tested as bad. They got me another one and I had them test it on their machine before I left the store and it tested as good. The machine only seems to spit out bad or good, not info on volts produced. I put it on the car an I get the following:

11.55 volts off the back of the alternator whether idling or 2000 RPM
12.15 volts at the battery
12.00 volts on a voltmeter whether idling or 2000 RPM
Slightly on the discharging side on the factory ammeter - needle drops sharply with flasher blink with flasher on

Is this just the state of auto parts store quality or does it seem I may have another problem? It seems that testing right off the back of the alternator should give a good read. Would a bad voltage regulator cause it to show less? Would a bad ammeter cause this? The gauge needle does move when the flashers are turned on.

I am thinking I should go with the Tuff Stuff 100 amp squareback as the reviews my Mopar owners indicate that not charging at idle is a typical Mopar issue and this seems to solve it. If I do that I probably need to change my wiring to 10 or 8 gauge from 12 and bypass my ammeter. I hate to lose the original gauge functioning on the dash, but might need to go that route. Do most of you that go that route just have a dead gauge in the dash and a separate voltmeter, or have a ammeter to voltmeter conversion done by Redline etc. on the existing ammeter?

 

[moparmarkk]

go get a voltage regulator,you need at least 14.0 volts coming out of the alternator to charge the battery,mark

 

[PurpleBeeper]

I agree with Moparmarkk.....cheap & easy to install. And if that doesn't do the trick....
1. Check, clean, or replace your ground wires to battery/frame/body
2. Try O'Reilly with a store manager that at least knows where the key goes on a car (not that easy to find). Their testers can give you all the information you're looking for (with a knowledgeable person running the test). A lot of the aftermarket stuff is hit-or-miss.

 

[Vermont Rock]

I don't think you will find a solution doing one test at a time. I agree with the guys above that there might be more to look at than just the battery or alternator. Find a GOOD shop that specializes in charging systems and have them check the entire system. By tracing the system from one end to the other, you'll find where the voltage loss is happening. And it might not be where you've been looking. Most of these cars have had several owners that performed maintenance without any real knowledge of what they were doing. Also, these are old wiring harnesses that could have lost a few strands, had poor splices or have corroded terminals. This stuff is hard to detect visually. Good luck & let us know what you discover. Rocket

 

[67GTX440]

I ordered a new voltage regulator and battery to engine and engine to firewall grounding strips. If this doesn't work, I will try to find a shop that can sort it out. I have a new engine wiring harness, but I don't want to tackle that until this issue is sorted out. I am taking baby steps. First got car to start and run consistently after installing new dash wiring harness. Second got all lights, signals and gauges working. Getting battery to charge and stay charged is the latest objective.

The wiring in the engine compartment is a mess and every wire the prior owner replaced looks to have come off the same spool of red wire. I have a red wire, and another red wire and another red wire instead of blue, green, yellow etc. I don't mind trial and error repairs when the parts are fairly cheap and I have no way to know how old the part in question may be. Could be 48 years old, could be 3. For all the things that don't work on a 48 year old car, it is amazing how many still do.