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Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 02, 2022 01:08PM

I am going to start the trouble shooting tonight but in the mean time I thought I might get some hints on what is going on with my charging system from y'all.

Set up:
- Good Die Hard battery; not much more than 5 years old if that (I'll check the date)
- Replacement Alternator installed less than 10 years ago, maybe as recent as 6 years
- Solid state external voltage regulator, about as old as the alternator

What happened:
Car died last night at the airport arrivals curb (picking up my nephew). Battery was dead and would not restart. (a good excuse to stay parked at the curb, BTW). AAA came and jumped me OK. The tech said its the alternator (he had a gizmo hooked up to the battery while running). I didn't think to ask if his assessment included the voltage regulator. We made it home (10 miles) keeping the rev's way up. Lights were dim but just before we pulled off of the freeway, the lights got bright, I'd even say normally so.

So I charged the battery overnight. This morning the voltage was ~12.5 V with and without the car running (maybe 0.1-0.2 volts less running). I even checked the voltage at the back of the alternator when running; same result. This tells me the alternator is not charging. When I got to work (30 miles, keeping the revs up), I checked the battery voltage running and it was ~14.5. This tells me the alternator is charging.

This smells like an intermittent problem. Or maybe I don't know what I am doing. Both of which would make my troubleshooting inconclusive.

Should I pop a bottle of wine tonight, watch the boob-tube and just order a new alternator and regulator?

James
65 Corsa
SF Bay Area

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Re: Alternator isn't charging except when it is charging
Posted by: Frank DuVal ()
Date: November 02, 2022 01:36PM

Not quite yet. Have a piece of wire? Open the shop manual and see which of the two terminals in the two terminal connector on the back of the alternator is F field. When you first start the car and voltage is 12. whatever, jump between battery positive and the F terminal and see if the voltage jumps to 14 whatever. If so, voltage regulator is bad. If voltage stays low and later in the drive comes up, alternator is bad. Probably just brushes. They can be changed with few tools.

Frank DuVal

Fredericksburg, VA

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Re: Alternator isn't charging except when it is charging
Posted by: jfreez ()
Date: November 02, 2022 02:15PM

I had a similar situation with intermittent charging on a newer car. kept loosing charging, at autozone the machine said it was good, but I kept having the problem. I noticed it only lost charging once the alternator got worm. I opened it up and I found that where the brushed made connection (the comutator I think) the copper had warn through, so as soon as the shaft expanded with heat, I would loose continuity.

you should be able to find an alternator rebuild kit pretty cheap, depending upon your model.

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Re: Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 04, 2022 04:07PM

Update: I did the field winding test as Frank suggested and I got 18 volts at the battery. Good alternator. Bad regulator.

Thank you Frank!

BTW, the 65 manual has a really good write up on how to set up and conduct this test.

James
65 Corsa
SF Bay Area

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Re: Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 21, 2022 12:15PM

Update:

Finally got to replacing the regulator. Still no charge.

Lacking an X chromosome, I just now noticed the GEN light does not come on when it should. I am not sure how long it's been that way. I replaced the bulb and still no light

The wiring harness looks more or less original, though it doesn't seem to be totally pristine (what one would expect after 50+ years I suppose)

I'll be doing a deep dive into the manual but any advice on where to look would be much appreciated.

James
65 Corsa
SF Bay Area

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Re: Alternator isn't charging except when it is charging
Posted by: American Mel ()
Date: November 21, 2022 12:44PM

You have NO "X" Chromosome??? eye popping smiley confused smiley

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

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Re: Alternator isn't charging except when it is charging
Posted by: MattNall ()
Date: November 21, 2022 12:47PM

May be the NEW regulator! All are solid-state now.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

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Re: Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 21, 2022 01:27PM

According to some, I am missing one of my X chromosomes.

[www.quora.com]

The regulator is a new electromechanical one (i.e. old school). Solidstate versions are either $100 (NAPA) or out of stock (Rock Auto)

James
65 Corsa
SF Bay Area

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Re: Alternator isn't charging except when it is charging
Posted by: jfreez ()
Date: November 21, 2022 03:15PM

you may be missing an X chromosome, but you have a Y chromosome. I could go way into this topic, I have a BS in genetics, but I don't want to put everyone to sleep smiling smiley

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Re: Alternator isn't charging except when it is charging
Posted by: American Mel ()
Date: November 21, 2022 04:18PM

jamesolefjensen Wrote:
-------------------------------------------------------
> According to some, I am missing one of my X chromosomes.
>
> [www.quora.com]
>



Ahh!
The way you worded that, it sounded like you had ZERO X chromosomes.
What ever person implied that has no working understanding of the XY mechanics.
With women having TWO X's, and Men having an active X, and an active Y, it is the poor women who are lacking.
In Men, both chromosomes are actively contributing to their genetic make-up.
IF anyone is incomplete, it is women who would be considered Genetically Deficient, since their second X is deactivated.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

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Re: Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 21, 2022 06:15PM

Small update on the problem:. I am pretty sure I am getting 12 volts on both wires coming to the bulb.

James
65 Corsa
SF Bay Area

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Re: Alternator isn't charging except when it is charging
Posted by: oldqmguy ()
Date: November 21, 2022 11:10PM

IF you are getting +12 Volts on both wires going to the bulb you have the wire from the Regulator in the wrong place or the Regulator is telling the wire that the Alternator is charging!

The bulb gets +12 Volts from the Ignition Switch. The wire that goes to the Regulator is "switched" BY the Regulator from GROUND (no charging) to +12 Volts (Alternator is charging) so the bulb will go out!

I hope this helps!

Dale cool smiley

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Alternator isn't charging except when it is charging
Posted by: FLSteve ()
Date: November 22, 2022 06:36AM

A 5 year old battery is where I would have started.

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Re: Alternator isn't charging except when it is charging
Posted by: jamesolefjensen ()
Date: November 22, 2022 08:28AM

Thank you for all the suggestions. I am chipping away at this and working my way through the manual diagnostics.

So far, here's where I am.

Car starts and runs. While doing so, voltage out of the back of the alternator and at battery terminal is only ~12.3 volts. (I've exited the field terminal and the alternator is good and just installed a brand new regulator)

With engine not running and the key on, I'm getting ~12.2v on the center contact of the GEN light bulb socket and ~12.0v on the socket side contact (definitely not the same voltage). I'm getting these readings with and without the regulator 4 pin connector connected.

With the Off (and engine not running), both bulb contacts are 0 volts.

I am not sure what this means but I am pretty sure one of the socket contacts should be 0 with the key on and the regulator disconnected

My best guess so far is I have a 12 volt short somewhere in the harness. Oy vey.

James
65 Corsa
SF Bay Area



Edited 2 time(s). Last edit at 11/22/2022 08:34AM by jamesolefjensen.

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Re: Alternator isn't charging except when it is charging
Posted by: Frank DuVal ()
Date: November 22, 2022 09:20AM

There is a resistor in parallel with the lamp socket. So never 0 volts with the lamp out and key on. Well, that's what the diagram on 6Y5 shows. But I cannot find the resistor in the wiring diagram for the body on 12-24 to 12-27.

Frank DuVal

Fredericksburg, VA

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Re: Alternator isn't charging except when it is charging
Posted by: RexJohnson ()
Date: November 22, 2022 10:25AM

Are you taking the readings at the socket with the bulb in or out? With the bulb in and the wires unplugged at the regulator I would think that both sides of the socket would be the same.

RJ tools
Salem,Oregon

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Re: Alternator isn't charging except when it is charging
Posted by: oldqmguy ()
Date: November 22, 2022 12:51PM

OK, here is how the Gen/Fan light works:

The Bulb Center Contract is supplied +12 Volts (POSITIVE 12 Volts) from the Ignition Switch in the ON and Start positions.

The "sleeve contact" (connects the metal barrel of the lamp) is connected thru several connectors back to the Regulator Terminal 4.

The Regulator has 4 Terminals. Looking at the Regulator in its normal mounting position, the Bottom Terminal is "F" (for the Field winding). Counting UP are terminals 2,3 and 4.

Disconnect the wiring from the Regulator, remove the bulb, and turn on the Key (I would disconnect the wires at the Positive side of the Coil to prevent damage to the Points and Coil before making this test)!

Measure the voltage at the Center terminal of the socket - you should see +12 Volts.

Check the 'sleeve' of the socket - you should see 0 volts.

Put the bulb in the socket and you will see +12 volts (it is feeding thru the filament of the bulb, but with the 'sleeve' disconnected there is no current being drawn so you see the same voltage).

Take a Jumper cable and Ground the Brown Wire that goes to Terminal 4 on the Regulator (this is AT the Regulator position). The Bulb should light!

If that test works - Bulb lights when the Brown Wire is grounded at the Regulator - the problem is in the Regulator or its wiring.

If the Bulb DOES NOT LIGHT when the Brown Wire is grounded, you have a problem in the wiring harness from the Engine Compartment to the Dash.

Make sure the Regulator is GROUNDED! It won't work if it can't 'see' the Negative side of the Battery!

These are the steps I would take if you brought the car to me and said "fix it!"

Dale

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Alternator isn't charging except when it is charging
Posted by: Frank DuVal ()
Date: November 22, 2022 06:16PM

Speaking of brown wire issues, a club member had a non-charge late model at a Virgina Vair Fair and Jim Simpson and I troubleshot the system and found a break in the brown wire in the harness up over the rear axle. I forgot if it was rodent damage or prior owner issues.

Frank DuVal

Fredericksburg, VA

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Re: Alternator isn't charging except when it is charging
Posted by: PGVair ()
Date: November 23, 2022 01:40PM

Yes Frank, that was me.

I forgot about that problem with my car when I first read this thread. Before I bought it, a mouse had chewed the wire over the rear axle. The PO told me about it when it happened and that he replaced the harness. As it turned out he had spliced the wire back together but the splice had come apart. Once I got the car home I made an improved splice repair. No more problems since. One of these days I'll replace the harness...maybe...someday.......possibly...

My symptoms were similar. Frank & Jim installed a jumper across a couple of the regulator terminals to make the alternator charge to get me home. At least knowing the wiring had been previously damaged I had an idea where to look.

I probably would have never figured it out on my own. They spent several hours under the dash and elsewhere troubleshooting.

Wade

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Re: Alternator isn't charging except when it is charging
Posted by: TIBCO ()
Date: November 23, 2022 06:34PM

Okay, so in keeping with the original post, let me share my problem. The car is a 64 Monza, 110 HP. It has bee upgraded to the 65-69, original 37 amp alternator. It began showing 16.5 volts while charging. Today we installed a new, non-electronic regulator for the 65 and up cars. It is a Standard Product.

I checked the alternator according to Frank's instructions above and at idle, the alternator put out 16.1 volts. So, I believe the alternator is fine. With the new voltage regulator, there is a slight discharge when idling at about 750 RPM, it's an automatic. When we rev it to 1000 RPM or better, the idiot light goes out, and it shows 14.4 volts at the battery. We also tightened the belt.

Any thoughts would be appreciated.

Cliff Tibbitts
Nicholasville, KY
CORSA, CKCE, Derby City Corvairs
66 Monza, 140/4sp

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