# Charging System issues



## Thurber73 (Mar 7, 2013)

1968 LeMans Gen light comes on and no charge going to the battery. Alternator tested good and just replaced the external Voltage Regulator but still no charge going out. Before it quit charging completely the Gen light would come on some when I stepped on the accelerator some.... Whats going on here?


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## BearGFR (Aug 25, 2008)

Are you positive that its not charging? Or is the problem just that the light is on...

Bear


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## Thurber73 (Mar 7, 2013)

Hey Bear,
Yeah very sure its not charging if left running it sucks the battery down and I have a tester that confirms this as well. Just had the alternator tested at the parts store again this morning and its all good, they even ran it several times to be sure. They are getting me a different Voltage Regulator that looks much more like the original than the other one I got from them. I had seen a customer review that stated the spades on the regulator turned out to be connected differently internally and we checked that at the parts store and sure enough they were. I will know if they got me the correct one tomorrow when it comes in. Any thoughts or ideas are very welcome coz my head hurts from this thing. thanks, Jon


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## BearGFR (Aug 25, 2008)

Ok then... if you know the alternator is working it just about has to be a problem with the regulator.

Good luck...

Bear


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## jetstang (Nov 5, 2008)

Hmm, are you getting 13 volts plus while running, charging? For $50 you can get a single wire self exciting alternator from Autozone with a lifetime warranty, then run a 10 gauge wire straight to the battery and ditch all the old stuff. I do that on my cars, then run a volt gauge to confirm it's charging. Your's may be a wiring issue to the gauge, or to the regulator. Best of luck.


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## Matthew (Feb 11, 2011)

Jon, I agree that it sounds like a voltage regulator. If by chance you are going to Autozone, you are likely getting the VR715 Duralast regulator. It's the right one, but this regulator is poor quality and you would not be the first to have a bad one straight out of the box. Recommend you go to NAPA. The replacement regulator will not look like the original because it is solid state electronics. Regards, Matt


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## Thurber73 (Mar 7, 2013)

I have not had a chance to investigate yet because the really cold weather has finally come to stay here in Cleveland and I am too much of a sissy to lay on the freezing garage floor , but I need to look for a fusible link that has burned down at the starter solenoid...it could be crapping out the entire system for me.


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## Matthew (Feb 11, 2011)

Jon, the fusible link you are referring to is on the starter end of the solenoid wire (purple). Your starter would probably not crank if that link were bad. Did you try a new voltage regulator yet? Regards, Matt


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## Thurber73 (Mar 7, 2013)

Matt, I have replaced the regulator even though the original tested out OK. Are you sure its the purple wire? I found another post that said the fusible link was in the small Red wire at the starter/battery cable connection on the solenoid. My Pontiac service manual says the link should be up top along the left valve cover and be a 5" long loop of wire sticking out of the harness. Now I am totally confused... I am currently having trouble getting to the wires on the starter solenoid there isn't much room. I was going to remove the starter motor and disconnect the wires and test them at either end looking for a burned link or break. I have taken the two long mounting bolts for the starter out but can't get to the one for the bracket on the end of the starter. Uggghhh GM engineering at its best.


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## the65gto (Oct 9, 2008)

I had charging problems once where I replaced battery and alternator, regulator, still the same problem. Had 13.8 vdc at the rear of the alternator, 11.5 vdc at the battery. When it was all over and done with, I removed the starter to find the red wire coming from the alternator to the big post on the starter was covered with a heavy coating of dark green crud. Cleaned up the lug and had 13.8 @ the battery. 

As far as getting the starter in/out, sometimes it is a breeze other times its a PITA especially when its cold out and you laying in a pile of snow or rain.:lol:


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## Matthew (Feb 11, 2011)

Jon, will not disagree with the service manual, but I have not encountered the loop you are talking about. That said, if the fusible link were bad, I think you would not be able to start the car. But, I have been wrong before, just ask my wife. Matt


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## Thurber73 (Mar 7, 2013)

Well I have exhausted all possibilities that I can come up with and tested everything I can; still no solution. I was speaking with a very knowledgeable friend that said its probably my alternator even though it tested good several times he tells me that if a diode is going bad it could still test good but not put out a charge.

I am therefore going to purchase a new one wire alternator; on the off chance he is wrong I will still be putting a charge to my battery and bypassing whatever the problem maybe


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## jetstang (Nov 5, 2008)

If the charging circuit isn't working, you can leave all the original wiring hooked up so it looks original, and just have the 1 wire to the alternator, and bury it in some sleeving so it doesn't show. I ran the wire behind the booster, then through the fender to hide it. Or just hook it straight so it's easy to troubleshoot. My 1 wire started acting up, gauges would show charging, then cut out and not charge. Replaced the alternator, but it tested good. Then found my old negative battery cable in the fender with grounds attached, doh, replaced the ground cable during motor swap.. Hooked them up to the new cable and actually grounded everything, instead of grounding against the inside of the fender irradically, and all was good, may want to look for a previous oops, grounds are important.


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## BearGFR (Aug 25, 2008)

If you're not getting 14.4 volts (or very close to that) when using a meter to measure across the battery terminals with the engine running, then you're not getting "enough" charge. If the problem isn't the alternator, and if it's not the VR, then it just about has to be in the actual wiring. Bad ground, degraded + side cable that now has too much resistance. Run the same check with the meter, only directly at the alternator output terminal. If you've got plenty of "juice" there but not at the battery, start looking problems in the grounds/wiring.

Bear


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## Thurber73 (Mar 7, 2013)

The one wire alternator is installed and charging like a champ...yahoooo! Last Saturday was the first day warm enough to play in the garage without getting frosted nutcicles.


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## Thurber73 (Mar 7, 2013)

Onto the next adventure...I've got a stock 350 in my LeMans and looking to upgrade the intake and carb. I've pretty much decided on the Edelbrock performer series 2156 low rise. I have been looking at Holley 650 cfm carbs, does anyone have a suggestion as to which one I should go with?? Looking primarily at 0-80783c (4150) and the 0-80555c (4175)


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