16V charging problem

Jim68 BC · Jul 4, 2023

rp930 said:
Ohm readings are not reliable for checking the cables. Check for voltage drops with the system active. I agree grounds could be a problem.

fairfax1000 said:
You have a circuit issue that has to be resolved with the GEN light. I would pursue that first.

yes , that seems to be where we are heading.
Thanks for your help. I’ll keep you posted if you like.

Jim68 BC · Jul 4, 2023

Jim68 BC said:
yes , that seems to be where we are heading.
Thanks for your help. I’ll keep you posted if you like.

we think there is some sort of cross over in that area. It may be causing the system to run in series & returning more volts then needed back to the battery.

dhutton · Jul 4, 2023

So is your wiring the same as I posted in the two pics?

fairfax1000 · Jul 4, 2023

Jim68 BC said:
Hello,
We’re having an issue with our ‘68 Camaro 396. The charging is showing 16V at idle. At times it will drop to 14.8 at load.
We have replaced the alt. once, the regulator twice, we’ve replaced the system with a new alt. with an internal regulator. It has new wire harness for the engine bay. We’ve bypass the horn relay. Removed the dash circuit board, the grounds are good. Changed batteries. Still no luck.
Any suggestions, thanks

What was the original issue?

Jim68 BC · Jul 4, 2023

dhutton said:
So is your wiring the same as I posted in the two pics?

At this point I would have to say , yes. The engine bay harness are new. We hooked them up as we replaced the old one. Also checking with a schematic.
The dash harness probably is original. It was already hooked up & the wires colours match correctly with the schematic.
The next stage , I guess is to unravel the wire harness tape & see what shows up.

dhutton · Jul 4, 2023

Are you using anodized alternator bracket? Ground your alternator case to the engine block.

allanjs · Jul 4, 2023

Jim68 BC said:
We bypassed the regulator plug, 1 to 4, 2 to 3 then adapted the alternator plug with some grumps.
I don’t think the problem is with the alternator/internal regulator setup, we just installed it because it was there. We’ve returned it to its stock setup. We just did it to see if it would make a difference. The problem hasn’t varied from the get go.

The only reason I know of to jump these terminals is if you are using a one wire alternator. Even if using the jumpers, you loose the gen light feature. That's the detriment of using a 1 wire alternator on these old cars. There may be a work around that I'm not aware of. There's a bunch of Youtube videos discussing this problem.

Jim68 BC · Jul 4, 2023

dhutton said:
Are you using anodized alternator bracket? Ground your alternator case to the engine block.

It’s just a stock bracket, we could run a separate ground .

dhutton · Jul 4, 2023

It’s worth a try.

dhutton · Jul 4, 2023

Similarly make sure your voltage regulator is well grounded. If the screw is rusty it’s not well grounded.

Jim68 BC · Jul 27, 2023

We decided to go with a one wire alternator, seems to have solved the problem.
We think that it’s due to the old dash wire harness.
We feel that the resistance built up from the ages was causing the regulator to adjust the voltage upwards.

16V charging problem

Jim68 BC

Jim68 BC

dhutton

fairfax1000

Jim68 BC

dhutton

allanjs

Jim68 BC

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dhutton

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