Charging issue

[cheveslakr]

Can't get this one solved........67 elky had new AutoZone 715, AC Delco alternator and it won't charge. Lots of little stuff I've addressed, loose connection on the VR-715, solved, iffy body ground, solved, replaced alternator, swapped VR with a known good one. I get 12.25 volts at the alternator and at the battery. Batt. indicator light on the dash. Here's the crazy thing, I played with the ground of the VR a bit, until I pulled the wire off, and the voltage shot up to 18+.......so the alternator has to be functioning, and the voltage reg. has to be functioning. I tracked down a couple iffy grounds and nothing changes. Don't know where to go next...........

 

[Shovelrick]

Have you tried another VR? I’m guessing thing is a completely stock system?

 

[Shovelrick]

I had to switch to an electronic VR when I put a 135 amp Load Boss alt on my car, but I was having Up/Down voltage problems, lights dim with low RPM that sort of stuff

 

[cheveslakr]

Yeah, I've got 2 new autozone VR-715s here, same results. The key here is I pulled the ground off, and the vols shot up to 18, so the VR was doing it's job, and the alernator is capable of putting out 18 volts. That's the stumper.

 

[kmakar]

How old is the battery?

 

[Chevelle_Nut]

Check the wiring back to the gauge from the VR and alt, when I reassembled a car the alt drove me crazy, found a loose connector.

 

[Shovelrick]

At the gauge could the wires get hooked up backwards? maybe 1 post is grnd sensitive?

 

[kmakar]

Typically on the gauge cluster it's a single terminal and the cluster is grounded.

 

[cheveslakr]

I'm checking with voltmeter at the battery and at the alternator, no change in voltage from static, to running at any rpm. Reads 12.5 volts. Dummy light is on. Battery is good, 2 different new VRs and 2 alternators, 1 near new, the other is new. Again, the new alternator I put on put out 18 volts when I pulled the ground off the VR, this would indicate the alternator is operable. I did take the first alternator into Autozone to have it checked and the gal fumbled with it for a bit, tried 3 different belts, talked a bunch of nonsense and told me it wasn't working. I had 0 faith she knew what she was doing, but I bought a new/reconditioned alternator anyway since I can always use it for another chevy.

 

[kmakar]

The hard thing I'm having an issue with reconciling is removing the ground from the VR and the the alt shows charging. Try this out: remove the ground from the VR again and read the amperage, then feel the wires. Undersized or shorting will heat the wires, but under a load it might not be letting the VR do its job.

 

[Chevelle_Nut]

I'm checking with voltmeter at the battery and at the alternator, no change in voltage from static, to running at any rpm. Reads 12.5 volts. Dummy light is on. Battery is good, 2 different new VRs and 2 alternators, 1 near new, the other is new. Again, the new alternator I put on put out 18 volts when I pulled the ground off the VR, this would indicate the alternator is operable. I did take the first alternator into Autozone to have it checked and the gal fumbled with it for a bit, tried 3 different belts, talked a bunch of nonsense and told me it wasn't working. I had 0 faith she knew what she was doing, but I bought a new/reconditioned alternator anyway since I can always use it for another chevy.

Do you have an alternator/starter repair shop around? AZ probably couldn't read it due to the external VR.

 

[Shovelrick]

Have disco’d the Neg battery cable while it’s running to see if it keeps running as it should if everything is working right

 

[cheveslakr]

It dies when disconnected, no charging. I'm going to check all grounds and if that doesn't reveal the witch, I'll start swapping parts from other cars.