Help 72 cutlass over charging

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Old May 27th, 2020, 04:40 PM
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Help 72 cutlass over charging

1972 olds cutlass supreme 350 Looking for help changed alternator and voltage regulator and battery readers 16.5 to 17 volts when engine is reved up any help would be appreciated cleaned all grounds and added some also
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Old May 27th, 2020, 05:38 PM
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Either the meter is bad, test it against another or the voltage regulator is bad.

If the reading is accurate it will boil the battery, blow light bulbs and possibly damage accessories.

Good luck!!!
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Old May 27th, 2020, 05:40 PM
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Any wiring mods or repairs been done that you can see?
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Old May 27th, 2020, 07:01 PM
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Originally Posted by Sugar Bear
Either the meter is bad, test it against another or the voltage regulator is bad.

If the reading is accurate it will boil the battery, blow light bulbs and possibly damage accessories.

Good luck!!!
ok well meter is good I have 17.2 at the alternator when revving up the engine and about 17.02 at the batterie and both alternator and voltage regulator are new
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Old May 27th, 2020, 07:03 PM
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Originally Posted by Sugar Bear
Any wiring mods or repairs been done that you can see?
some wiring mods but all separate running off the batterie with an in line fuse
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Old May 27th, 2020, 07:18 PM
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Originally Posted by 72cutlass350rocket
both alternator and voltage regulator are new
New does not necessarily mean good.

It is obvious that the alternator works since it is putting out voltage, so there is something wrong in the regulator circuit.
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Old May 27th, 2020, 07:36 PM
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Originally Posted by Fun71
New does not necessarily mean good.

It is obvious that the alternator works since it is putting out voltage, so there is something wrong in the regulator circuit.
ok I'll order an other one.... thanks again for your help
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Old May 27th, 2020, 08:57 PM
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Try to get a different brand of regulator if you can. It's not that uncommon for parts to have bad batches. Two or more bad ones in a row can really challenge your confidence in your dagnosis...been there with new thermostats and rebuilt wiper motors.

Good luck and please keep the post updated.
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Old May 28th, 2020, 10:00 AM
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Originally Posted by Sugar Bear
Try to get a different brand of regulator if you can. It's not that uncommon for parts to have bad batches. Two or more bad ones in a row can really challenge your confidence in your dagnosis...been there with new thermostats and rebuilt wiper motors.

Good luck and please keep the post updated.
your telling me just tried an other regulator and still the same and even ran a ground direct to the negative on the batterie and still climbs to 17 volts when on the throttle
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Old May 28th, 2020, 10:01 AM
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Originally Posted by Fun71
New does not necessarily mean good.

It is obvious that the alternator works since it is putting out voltage, so there is something wrong in the regulator circuit.
just tried an other new one and still the same
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Old May 28th, 2020, 11:38 AM
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You might try a different Alternator. 17v output seems a bit high.
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Old May 28th, 2020, 12:14 PM
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Originally Posted by RandyS
You might try a different Alternator. 17v output seems a bit high.
ya I'm thinking the same at this point.... maybe a single wire alt with a built in regulator and some electrical tape over the bat light in the dash lol
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Old May 28th, 2020, 12:34 PM
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Originally Posted by Fun71
there is something wrong in the regulator circuit.
Note that I did not say the voltage regulator itself was bad. Seems as if you ruled out the voltage regulator as the issue, so check all of the wiring from the regulator to the alternator.
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Old May 28th, 2020, 02:37 PM
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Originally Posted by Fun71
Note that I did not say the voltage regulator itself was bad. Seems as if you ruled out the voltage regulator as the issue, so check all of the wiring from the regulator to the alternator.
ok I followed everything back and did some reading and #1 on the alt should be blue and #2 should be white correct? With a jumper from #2 to the nut on the back of the alt? I'm almost thinking my original alt was internally regulated and my new one is not or something... I'm completely lost on this one
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Old May 28th, 2020, 02:39 PM
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Can you post a pic of the back of the alt?
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Old May 28th, 2020, 03:02 PM
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Originally Posted by RandyS
Can you post a pic of the back of the alt?

Orginal alternator

New alt
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Old May 28th, 2020, 03:32 PM
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It looks like the pictures are of at least 2 different alternators. Are you getting the same results with multiple alternators?
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Old May 28th, 2020, 03:47 PM
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Originally Posted by stellar
It looks like the pictures are of at least 2 different alternators. Are you getting the same results with multiple alternators?
I agree, those are not the same alt in both pics....... are you messin with us??
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Old May 28th, 2020, 03:49 PM
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the proform 66445n is a 70amp internal voltage regulator alternator
the pictured ac delco unit in your fist post is an external voltage regulator alternator
What wiring did you change to run the AC Delco?
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Old May 28th, 2020, 04:16 PM
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Originally Posted by nicks1966
the proform 66445n is a 70amp internal voltage regulator alternator
the pictured ac delco unit in your fist post is an external voltage regulator alternator
What wiring did you change to run the AC Delco?
lol sorry you guys but here's what I'm thinking and I'm not a mechanic just kind of learning and winging my way so the original alt to me I'm assuming is an internally reg alt "the chrome one" and the one I bought for the car from our local parts store is externally reg and just wired it the same as it was so I'm now assuming that I have a red wire that goes to my voltage reg hiding somewhere that should now be hooked up to my alt since I can't return it and have a pile of voltage regulators lol so where does my red wire go from the back of my alt to make everything back to factory? I'm assuming to the voltage regulator but not sure exactly..... and if you think this is bad it took me a week to figure out my dist turned backwards lol but I'm learning as I go new disc brakes new 3.90 rear 4 speed Muncie some body and paint all new to me but I got those far an mostly from fine folks on here.... not many ppl to talk to about olds up in northern ontario Canada
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Old May 28th, 2020, 04:36 PM
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Here is a typical difference in wiring, the slashed wire jumpers are installed to convert to an internally regulated alternator.
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Old May 28th, 2020, 05:24 PM
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If using the internal alternator do not connect the external regulator. follow the diagram in post 21. If you want to return to the original external set up we can help with that.
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Old May 28th, 2020, 05:29 PM
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Originally Posted by oldcutlass
Here is a typical difference in wiring, the slashed wire jumpers are installed to convert to an internally regulated alternator.
ok now I'm getting somewhere .... is it normal to have the starter wire piled on that some post on the horn relay? I thank you so much and apologise for my stupidities
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Old May 28th, 2020, 05:32 PM
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Originally Posted by stellar
If using the internal alternator do not connect the external regulator. follow the diagram in post 21. If you want to return to the original external set up we can help with that.
I think the original was stuck as it was plugged in and everything seemed to work but only but 150 miles on it kind of why I thought the external alt was what I needed
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Old May 28th, 2020, 09:18 PM
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So everything in the diagram was correct but I had to switch the white and blue wire but ya 13.97 I am so happy thanks again to all of yous for taking the time to help me through this
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Old May 29th, 2020, 04:54 AM
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Glad you got it to work.
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