'73 Karmann Ghia Charge Light On

Moderators: Sluggo, Amskeptic

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

'73 Karmann Ghia Charge Light On

Post by mentalQtip » Thu Feb 28, 2013 12:42 pm

'73 coupe. Starts great and idles so-so. The generator light came not while driving but when I started it after driving about 20 minutes. When I checked it this morning the battery was at 12.5 volts and after starting was showing 12.0 volts. I've polished all the connectors I can find, pushed on the brushes, polished the commutator, and done the procedure of removing the leads from the D+ and DF terminals, grounding the DF one and reading the voltage from the D+ to ground on the generator body. That one I find confusing. Mostly if reads 0.0 but if I dig the probe at the ground on the generator body I get flickers of up to 20 volts. Just flickers. Does this mean that I'm not getting at good connection in my testing or is the generator actually showing flickers of charging?
Am I missing a test here that could comfirm my readings?

Thanks

Been polishing off the oxidation on the ghia with TR3 and I'm amazed at how shiny and pretty it is. I keep going to the garage to look at it again, even tho the pain job is chipping.

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Thu Feb 28, 2013 5:12 pm

mentalQtip wrote:'73 coupe. Starts great and idles so-so. The generator light came not while driving but when I started it after driving about 20 minutes.
I've polished all the connectors
pushed on the brushes
polished the commutator
removed the leads from the D+ and DF terminals, grounding the DF one and reading the voltage from the D+ to ground on the generator body.
Mostly if reads 0.0 but if I dig the probe at the ground on the generator body I get flickers of up to 20 volts. Just flickers. Does this mean that I'm not getting at good connection in my testing or is the generator actually showing flickers of charging?
Am I missing a test here that could comfirm my readings?
Pushing already annoyed brushes will not inspire them. Remove the brush from the holder and lightly sand the contact surface, both brushes.
Check your brown wire ground from the generator to the regulator, if the regulator is mounted on the firewall.
If the lousy reading you're talking about is cured by "digging" the probe into the metal of the generator, then the grounding problem seems to be with your test leads.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Fri Mar 01, 2013 10:58 am

Thanks Colin. I haven't pulled the brushes yet but I did look at the brown ground wire. It wan't there. so I pulled the wires of the generator and lifted the whole casing up and there it was, broken off inside. So what happens if you don't have the brown wire grounding on the generator? Also I have a black wire with a ring connector coming out of the same harness to the generator. Whats with that one?

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Fri Mar 01, 2013 12:05 pm

mentalQtip wrote:So what happens if you don't have the brown wire grounding on the generator? Also I have a black wire with a ring connector coming out of the same harness to the generator. Whats with that one?
Brown helps the regulator regulate the field current.
The black one is IIRC for the computer diagnostic that VW once upon a time had.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Fri Mar 01, 2013 2:25 pm

Colin. I spliced a wire in and I have a wire from the VR to the generator and well grounded. I discovered a VR that I had from the picknpull and slipped it in and voila, gen. light turned right out. I now know more about this engine and electrics than I did. Feels good.

Thanks

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Fri Mar 01, 2013 9:36 pm

mentalQtip wrote:Colin. I spliced a wire in and I have a wire from the VR to the generator and well grounded. I discovered a VR that I had from the picknpull and slipped it in and voila, gen. light turned right out. I now know more about this engine and electrics than I did. Feels good.

Thanks
Do some homework and see if you can verify that you have a correct regulator for the generator.
I think you have a 38amp generator that wants a 38amp regulator. If you have a 38amp regulator trying to extract from a 30 amp generator, things burn up after a few weeks or so.

The amperage value will be stamped on one of the "legs" i.e. 14V 30A or 14V 38A.
The 38amp generator is easy to see, it is so long that the fan housing plate is "indented" to give room for the length and still have an aligned belt.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Wed Mar 06, 2013 2:00 pm

Colin. When you were here you mentioned that the generator on this ghia was rotated 45 ccw form normal. Made it a little hard to see the numbers. Finally cleaned enough corosion off to see and did verify that it is 30 amps.
With 205T distributor and H30/31 pict it is running pretty well and I'm driving it more than I have in the six years I've had it.
Question: Do I time the 205T at 0 degrees or at full advance ideally?

Falling in love with this vw. Wife is jealous.

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Sat Mar 09, 2013 11:42 am

mentalQtip wrote:Colin. When you were here you mentioned that the generator on this ghia was rotated 45 ccw form normal. Made it a little hard to see the numbers. Finally cleaned enough corosion off to see and did verify that it is 30 amps.
With 205T distributor and H30/31 pict it is running pretty well and I'm driving it more than I have in the six years I've had it.
Question: Do I time the 205T at 0 degrees or at full advance ideally?

Falling in love with this vw. Wife is jealous.
A vacuum-only distributor can only be timed at 0* engine off.
There is no centrifugal unit to test at high rpm.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Wed Oct 23, 2013 7:01 pm

Back to the question of testing the generator in the ghia. Again I've tried grounding the DF post to the generator body and testing the voltage between D+ and the generator body. Try as I may I can't get any kind of reading on the multimeter, just scattered numbers all over the place. Sometimes if I dig hard I think(maybe?) that I see a real number, but no confidence in what I'm seeing. Could this be a clue to the poor charging I'm experiencing? Or just unrelated?

Joseph

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Thu Oct 24, 2013 8:26 am

mentalQtip wrote:Back to the question of testing the generator in the ghia. Again I've tried grounding the DF post to the generator body and testing the voltage between D+ and the generator body. Try as I may I can't get any kind of reading on the multimeter, just scattered numbers all over the place. Sometimes if I dig hard I think(maybe?) that I see a real number, but no confidence in what I'm seeing. Could this be a clue to the poor charging I'm experiencing? Or just unrelated?

Joseph
A) Polarize Magnets

Remove the fan belt. Slap a good battery on the ground near the engine.
Apply a jumper cable from the battery + terminal to D+ on the generator. Do NOT let it short or get stupid.
Apply a jumper from battery (-) to DF.
Generator will run a bit as a motor.



B) Check Output

Measure the voltage across the vehicle's installed battery. Should be about 12.6 volts with the engine off. As the engine speeds up, the voltage should increase to somewhere around 13.5 volts. If it does, the generator is working and charging the battery.

If the voltmeter does not go up with the engine running, first check to see that the generator brushes are not worn excessively. The hold down springs must not be touching the brush holders. When the brushes are worn to the point that the springs don't exert enough pressure on the commutator, you will get pitting on the commutator.

C) Full Output Test (make it very brief)

If the brushes check OK, do this test:

Remove generator wires to regulator.
Connect a jumper from DF on the generator to the generator ground screw or decent grounding spot. Now run the engine and measure the voltage from ground to D+ on the generator.

As you increase the engine speed, the voltage should increase to +35 volts or so at 3,000 rpm. Don't waste time here.
If it passes this test, the generator is good.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Thu Oct 24, 2013 5:17 pm

Thanks Colin. I did A) and went to
B) Starting voltage was 12.3. The voltage didn't increase with rpm. I checked the brushes and they looked great with lotta space between the springs and the brush holders.
C) While doing this test the numbers jumped all over the place but not as wildly as before. As usual tho after some seconds the numbers went to only a 1, and this was in the tens column with no zeros or other numbers on the screen. Whats with that? Voltage didn't smoothly increase with rpm.

However, when I replaced the wires on the DF and D+ and started the car it showed 14.5 volts. Too high? First time since I've had the car that the charging voltage has been that high.

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Thu Oct 24, 2013 6:47 pm

postscript. Well above idle I'm getting 17 volts. Has to be the voltage regulator, right? The 14.5 was at idle, so....?

kreemoweet
Getting Hooked!
Location: Seattle
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by kreemoweet » Thu Oct 24, 2013 10:21 pm

Consider the possibility that your digital multimeter is no damn good. Cheap little analog meters are perfectly adequate for this sort of testing. They can be a little
fragile, but when they go bad it's pretty obvious, and they're usually quite reliable.

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by Amskeptic » Sat Oct 26, 2013 7:32 am

kreemoweet wrote:Consider the possibility that your digital multimeter is no damn good. Cheap little analog meters are perfectly adequate for this sort of testing. They can be a little
fragile, but when they go bad it's pretty obvious, and they're usually quite reliable.
As per kreemoweet's post, then yes, voltage regulator after you have established that your grounds are all good.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 116,898 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 84,465 miles

mentalQtip
Addicted!
Location: Portland, Oregon
Contact:
Status: Offline

Re: '73 Karmann Ghia Charge Light On

Post by mentalQtip » Sat Oct 26, 2013 1:00 pm

ok. After realizing I have to change the setting on the multimeter from 20 volts to 500 volts,(flat forehead syndrome), I find that the reading is 70+ volts at high rpm. Thats on step C. Putting the wires back on D+ and DF on the generator I read voltage on the connections on the voltage regulator at D+ and DF and got 1.30 volts. That seems pretty puny. Does that mean I have a wiring problem between the generator and the vr?
I keep thinking the generator is putting out the voltage but somehow its not getting to the vr
I'm feeling pretty lost here.

Joseph

Post Reply