# LeMans -70 charges over 16 Volts



## Reuhkapelti (Sep 18, 2012)

HI! After installing a volt meter to the dash, I noticed some over charging... 16,2 V from the Battery terminals at 2000rpm and more. I went to the local speed shop and bought and installed a new (remanufactured) alternator. But still she overcharges. External voltage regulator, says the label on the alternator, when looked at it more carefully. Any alternatives when replacing it, or just put a new samekind of V-regu? I assume it sits on the firewall and has 4 pins on the side?

Wires under the hood are a bit messy, and I tried to find some easy way to get them in order, somekind of painless wire kit. I think they all consist too much stuff. I dont have a clima, power windows or -seats or -locks etc. Lights work well on both ends as flashers too. The connectors in the fuce box have some rust and some wires are cut and then put together again by false methods.
Any thoughts about this, thanks :seeya:.

-Ismo


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## Rukee (Feb 8, 2007)

Don't drive it, the battery could explode. Don't ask me how I know. Replace the VR and get that voltage down to around 14v.


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## jmt455 (Mar 26, 2012)

^X2

Rukee is correct; replace that voltage regulator before the battery is damaged.
Also, make sure the electrolyte levels are correct in the battery; with that high of a charging voltage, you've probably boiled off some of the the electrolyte.

Only add distilled water to the battery; tap water has too many chemicals in it.


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## Josh.AZ.GTO (Jul 11, 2009)

Rukee said:


> Don't drive it, the battery could explode. Don't ask me how I know. Replace the VR and get that voltage down to around 14v.


:agree


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## Josh.AZ.GTO (Jul 11, 2009)

jmt455 said:


> ^X2
> 
> Rukee is correct; replace that voltage regulator before the battery is damaged.
> Also, make sure the electrolyte levels are correct in the battery; with that high of a charging voltage, you've probably boiled off some of the the electrolyte.
> ...


:agree It is extremely important to only add distilled water anything else will ruin your battery.


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## PontiacJim (Dec 29, 2012)

I agree with the voltage regulator. You may have to go with a reputable aftermarket replacement from one of the Pontiac specialty companies. I had a problem with the charging system on my '68 Lemans. Make sure you have a good ground from the engine to the body via the ground strap - which often gets ripped off during the engine change and never gets put back on. Lesson 1 I learned. I went to my local Advance Auto and they did not have a listing for my Pontiac, however they had a listing for a 1968 Chevy truck and lo and behold, it sure looked the same to me and fit. Lesson 2, not all voltage regulators are the same. My battery would run down in charge and my engine would not run as crisp as when I charged my battery up on the charger. Figured this out after some time, but ran the car so little that I simply did the battery charger thing every so often. The next suggestion, if you don't have to have original, is to look into replacing the factory alternator and voltage regulator with an updated one-wire alternator that has an internal regulator. Say what? Yep, Year One has a nifty plug that goes in place of the voltage regulator to reroute the current (don't ask me how that works) so you can do this. I have the piece, but have not used it. I will be installing it on my present rebuild #2 of my '68 Lemans so I can use a late model alternator. Many hot rodders use the one-wire alternator with built in regulator and most later cars have them. I think these came out in the 1970's, and you won't have to worry about finding a voltage regulator the next time you need one-----miles away from home and in the rain.


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## Reuhkapelti (Sep 18, 2012)

Ok I managed to find a new V-regu from eBay, hooked it on and volts are now 15,0. Maybe I can leave it that way? INT. V-regulator sounds good, perhaps I will go for it later. The battery is fine, I added just a hint of the right kind of water though. 
Torq Thrust D wheels appeared to my garage with BFG tires, the project continues!


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## Rukee (Feb 8, 2007)

15v is right on the boarder of overcharging. I'd rather see it between 14-14.5v.


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## FlambeauHO (Nov 24, 2011)

I agree with Rukee


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## Reuhkapelti (Sep 18, 2012)

A new ground lead from the bat. neg. to chassis dropped the voltage to 14,2V. Actually it didnt have that ground lead at all. Now the first test drive is done, and the Ponu moves great! No leakage anywhere and it's really easy to spin the rear wheels... Well the tarmac was wet. But the set of four H4 headlights may be too much for the generator, and the charge droppes to 9V when at idle. I'll take the inner bulbs off and see if that helps. The new generator is only 55 amps. Now the new stereo with the extra amplifier and the 12" bassbox will eat a lot of power too.


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## Mr. Sullybun (Jun 27, 2012)

*voltage problems*

I also have a 70 Lemans with voltage issues. It constantly reads over 16 volts. I have blown all the dash and gauge bulbs and some fuses that blow as soon as I replace them. Just installed new voltage reg from Ames Performace. I will check out the neg ground cable. Any other ideas?


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## Reuhkapelti (Sep 18, 2012)

A new ground lead solved atleast my voltage issues. I disconnected also the inner headlight bulbs, as theres no need for them now, and I'm getting good voltage at idle too. I'm quite sure it will help on your case too, IF the new V-reg doesnt do the trick.


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## Rukee (Feb 8, 2007)

Where did you put the ground cable?


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## Reuhkapelti (Sep 18, 2012)

My car only had a ground lead from the battery neg. to the engine block, so I added a lead from there to the chassis too. Also the original generator was missing the ground lead, so I added that too when replacing that unit with a new one.


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## 68greengoat (Sep 15, 2005)

Here's some more grounding tips starting with post #13. You can't have too many...
http://www.gtoforum.com/f12/turn-signal-not-working-67-gto-27334/


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## Mr. Sullybun (Jun 27, 2012)

The voltage regulator did nothing to help. Ordered a 3 piece set of ground cables and was wondering where exactly should they go? I don't see any ground cables on my car except for the neg from the battery to the engine block.


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## olde-goat (Feb 1, 2009)

*Ground cable location*

On my 65 there are also 3 ground cables,I have to believe that yours would be similar

passenger head to firewall
coil bracket to firewall
passenger inner fender to frame

Also of course battery negative terminal to engine. Extremely important that your terminals, and bolts are clean and that you have good clean surface to bolt to. For extra insurance I use new serrated washers between all the connections.


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## Mr. Sullybun (Jun 27, 2012)

Installed the ground cables and it did not change anything. Any more ideas? I really need to get this fixed.


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## Iraq 69 (May 4, 2013)

I agree with olde-goat. There needs to be several engine, frame and body grounds. I solved several electrical issues with good, clean grounds om a Chevelle.
Marc


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