Alternator gauge pegs right when eng rev. Pics

ValR

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Alternator gauge near center when idle pegs right when revved. Alternator, regulator, ceramic resistor all new? Dome light brightens when revved. Removed neg battery cable stays running so i figured alternator ok. See pics. 63F4222F-3A67-40A8-A7FF-5608773B2038.jpeg 4091AEDC-042E-499D-A823-B97F1AC82B96.jpeg 6DFBCCCF-64EB-40F0-B480-6FFA78ED40CC.jpeg 86D70967-3A37-471F-8330-68AC784473E9.jpeg CB835518-3985-4897-9A6B-CC7F5B5BE059.jpeg
 

V.R.D

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check that amp gage it might be going bad they have been know to burn a car down to the ground with out even running. remove the negative battery cable for safety remove cluster and replace amp gage with anew style electronic gage.
 

ValR

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Aight. Btw. I measured some voltages just now. The alt and reg are putting out 16.5 v when i rev. 13.9 at idle.
 

ValR

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check that amp gage it might be going bad they have been know to burn a car down to the ground with out even running. remove the negative battery cable for safety remove cluster and replace amp gage with anew style electronic gage.

I've got a spare!! Boom

image.jpg
 

V.R.D

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ok that explains the pegged gage 16 is over charge no more than 14.8 the regulator is possibly bad.
 

ValR

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ok that explains the pegged gage 16 is over charge no more than 14.8 the regulator is possibly bad.

Roger that I just ordered a new reg. I will wait then to change gauge. I do notice tho gauge in car is a little right of center when off. But my spare is balls dead on centered.
 

V.R.D

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one thing to try run a ground wire from alt to engine and make sure the engine is grounded to body.
 

V.R.D

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ok i have seen a lot of charging system problems with bad grounds.
 

ValR

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ok that explains the pegged gage 16 is over charge no more than 14.8 the regulator is possibly bad.
Correction, i bought the regulator 20 years ago from autozone, and it looks new, so new reg onway.
 

ValR

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ok i have seen a lot of charging system problems with bad grounds.
Understood. Just be advised i have been trying to restore this car to stock and a lot of the connections and grounds have been reworked clean and tight. It probably is some ground tho.
 

V.R.D

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i see you have cleaned it a lot and seeing the d v o m tells me you seem to know what you are doing. check the bulk head connectors for melting and tighten them up over time the female will open and can make gremlins
 

ValR

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i see you have cleaned it a lot and seeing the d v o m tells me you seem to know what you are doing. check the bulk head connectors for melting and tighten them up over time the female will open and can make gremlins
Thx. Good idea on bulkhead connectors. The engine harness new but the bulkhead male original. Im gonna make sure there is some electr contact grease in there too.
 

72RoadRunnerGTX

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Properly maintained ammeters and related connections don’t “go bad” or “spontaneously combust” for no reason. Loose connections with high moisture exposure can lead to corrosion and resulting high resistance/heat damage while over-tightened connections will cause insulator failures.

In this case it appears to be a failed regulator, as mentioned the charging voltage is too high, contacts are likely fused together. I would look at electronic replacement versions of that regulator for mechanical reg cars.

Be sure there are no added loads at the battery posts, any vehicle electoral loads connected to the battery side of the ammeter will register as charging current on the ammeter.
 

ValR

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Properly maintained ammeters and related connections don’t “go bad” or “spontaneously combust” for no reason. Loose connections with high moisture exposure can lead to corrosion and resulting high resistance/heat damage while over-tightened connections will cause insulator failures.

In this case it appears to be a failed regulator, as mentioned the charging voltage is too high, contacts are likely fused together. I would look at electronic replacement versions of that regulator for mechanical reg cars.

Be sure there are no added loads at the battery posts, any vehicle electoral loads connected to the battery side of the ammeter will register as charging current on the ammeter.
New electronic version of regulator coming today via Class Indust. I will let ya know results.
 

ValR

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Update: Classic Indust. Regulator fixed it! Funny tho, the cover is upside down. Frickin chinese. Zoom in to see.

Edit: Tbh, i don't know where its made. If someone agrees the cover is upside down, I will look for made in stamp when i change cover.
Edit2: The cover is correct. Green wire is FLD. So is entire regulator mounted upside down? Cant be cause wires come out of harness at those connection spots. Hmmm.
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DFA5F816-BFEA-49C0-927A-EE68B2D04790.jpeg
 
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