VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Dead End ! Any Ideas Are Welcome!

Well guys I installed the new generator and polarized it. Engine starts well as usual. Voltage is still 6.19 at battery and just under 1.0 at the generator. When revving the engine there is almost no change.

I grounded the FLD wire and revved the engine as per instructions to determine if the problem is the generator or voltage regulator. The voltage ran up to about 7 volts. According to the test instructions that means the problem is in the voltage regulator. But I just installed the voltage regulator so I must have a wiring problem to / from the regulator.

The only electrical problem I haven't fixed on this car is the horn. I doubt this is the problem as I have disconnected it but I am stumped at this point. I hate to bring her to a shop. There aren't that many wires on this car!

Any guesses are welcome.

Thanks

Mike

Try another voltage regulator.

Don't forget to re-polarize the generator when you install another voltage regulator.

One question though. I'm not sure I understand the problem. How do you know the voltage regulator is bad? Have you depleted the batteries enough that need for the regulator to kick in and show charging?

Sometimes we think we have a problem when we don't.

Like I said though, maybe I don't fully understand the problem.

Charlie

It would be of interest to see what the ammeter reading was when the field was grounded and the voltage went to 7 volts. It is pretty simple to check for a wiring problem with the field connection. Just disconnect the field wire at the generator and at the regulator and run a separate test wire between the two.

You mentioned that you installed a "new" regulator. If it is not a rebuilt or NOS Delco unit then it could be junk. Some of the reproduction ones are garbage.

41: With the engine running the voltage at the battery should be over 7 volts - right? This is how the generator keeps the battery charged. I've also checked the generator at it terminal while revving the engine. I get less than 1 volt.

This is the first time I've dealt with 6 volt systems. It seems easy but I am missing something I guess. Are you saying the battery must drop below a certain voltage level then the voltage regulator kicks the generator in to allow over 7 volts into the system?

In 12 volt systems the charging system is always over 13 volts and is read at the battery. I've read this is the same with 6 volt systems too but please correct me if I am wrong.

Thanks,

Mike

Old,
Great idea! I was wiggling the wiring and the harness between the two but to no avail. I will try the jumper and see what happens - great idea. I should have thought of that.

I just ordered another voltage regulator but it was a cheap one too ($80.00) ? From Parts Geek. Bad move I guess!

Be sure you have a 6 volt negative ground regulator.
Also GMC generators look identical but are Positive ground.
I assume you have checked your wiring harness.
From your diagnosis, it sounds like the regulator is not giving the field wire the signal to charge.
If you generator continually charges to 7 volts, it will boil your battery dry.
Filling Station has 1940 - 54 regulators for $69.50. (800)841-6622.
Jim Carter's has them for $65. (800)862-1913

Thank you!