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66blackbird
07-29-2016, 11:06 AM
Ok, new member here, having issues with alternator charging.
Had my battery died a few days ago, and had to call for a jump start to get it home.
On the trip home I noticed the amp gauge was in full discharge all the way home.
I put the battery on the charger overnight, and got a rebuilt alternator the next day.
I put in the new alternator, and started the car, it was still in full discharge on the amp gauge. If I put a load on it, lights and brakes on, it would go to full charge, no in-between .
So I took a trip to Autozone and got a new voltage regulator, still no change, it either D or C, needle pegged one way or the other.
Put in a led volt gauge, and it's either 12.3 or 13.5
I checked the VR with the key on motor not running I get voltage on the green/red wire, the amp gauge goes to full D with key on.
Checked the white wire when it was on full charge, have voltage there too.
What else should I check?

Mark

jopizz
07-29-2016, 11:34 AM
Mark,

Assuming that the parts you replaced are good I would check the main wire connecting block where it goes through the firewall. They can get corroded or worse overheat and cause wires to short out. Take that apart and make sure the connections are clean. I have seen many bad VR's right out of the box so that's still a possibility. A bad amp gauge is also a possibility.

John

66blackbird
07-29-2016, 05:38 PM
I was wondering if the coil should draw enough amps to peg the amp gauge on full Discharge when you turn the key on?
I tried just acc , and it just dipped slightly towards D, then when turned on to start it slams the needle all the way left into discharge.
I pulled the positive lead off the coil, and it only dips slightly left again.
Could the coil be shorting out, but still working?

jopizz
07-29-2016, 08:06 PM
I can't say that I've ever seen a bad coil cause the amp gauge to peg. I guess it's possible but I would look elsewhere first.

John

66blackbird
07-29-2016, 08:54 PM
Ok, not the coil, I swapped it out with a old one, does the same thing.
Only difference is the car runs like crap now and still does not charge at all?

jopizz
07-29-2016, 09:00 PM
I don't like swapping out parts to fix electrical issues. All you are doing is spending alot of money and not fixing anything. Make sure your wiring is good first before replacing parts. All the wiring diagrams are in the Technical Resource Library.

John

66blackbird
07-29-2016, 10:33 PM
Ok, it's fixed now.
Took everything apart and cleaned and sanded all the terminals to the grounds, starter relay, voltage regulator, and the alternator. Also put back in my good coil, and the original voltage regulator that was in the car.
Now the amp gauge stays in the middle and barely moves at all.
It was getting 14.8 volts cruising the freeway, and 14.2 at idle now.

jopizz
07-29-2016, 10:56 PM
Congrats on getting it fixed. More times than not it's something simple.

John

YellowRose
07-29-2016, 11:42 PM
Hi Mark, I am glad you found our Forum and that we were able to help you locate and fix that problem. I don't know how many times John and Dave ~ simplyconnected and others have said that when facing a problem similar to that, to first check your ground connections. Start by taking them loose, cleaning them, and where they attach to. Make sure you have good, solid tight grounds after cleaning them. So many people start throwing parts at a problem only to find out that it is often caused by a bad ground, not the part. I am pleased that you were able to find the problem and fix it. I guess you will have some back up parts now...

66blackbird
07-30-2016, 10:13 AM
Well the new rebuilt alternator was probably due anyways. The one that was in there may have been original, or at least 25 years old?
True I didn't need the $22 autozone voltage regulator though, so it's a spare now.

Mark