I'll be there around 6-ish. Two words - Cold Beer.

Doc

 

If the alternator was updated then Porsche also used a 68 ohm 5 watt resistor in place of the old resistor but ONLY if the red alternator light fails to go out after starting the engine the exciter circuit is too weak. Sounds like you are not getting the red light at all ! circuit board problem ??

 

ROG: Disclaimer -- If you've seen my other questions on the Big Relay thread you know how much I don't know about this electron stuff. FWIW, the alternator doesn't "alternate" until the engine exceeds 2300 revs. Perhaps a contributing factor when you are taking readings. Once I have oil up the engine, I get a little BWAA going to ensure the alternator is excited.

 

Jim,
Circuit board looks fine, however I should be able to check it once Doc arrives.
Cannot see any breaks and it looks like new.

Does the 82 need to be reved to 2300rpm to get it charging?
I am testing at idle speeds.

Mt GTS reads 14V at idle.

 

Steve, I think the alternator doesn't alternate until the alternator reached 2300 revs, which is much lower crankshaft speed. The alternator will provide current at idle(7-800 crankshaft), but it will not be much.

Doc

 

Doc,
At idle if everything is OK I should see 12v + not less than 12v?
Roger

 

Correct.

Car off, batt at normal charge, voltage at batt approx 12.2V.
Ignition on, batt approx 12V.
Starting batt 10.3-11.7V.
Just after start 12.4V and climbing.
Rev to 2500RPM - 12.8-13.6V
Rev to 4000RPM - 13.2-13.9V'

It's important to watch the voltage as different things happen. When the alternator is charging the voltage should not sag. It should be above 12.3V. Turn on the lights and the voltage should not go donw much. The alternator should support the load with a bit more RPM. Insure your batt is fully charged when starting these tests.

Doc

 

Roger... as Mark (& others said) you need the bulb in
and on. How'd you check continuity - bulb &
resistor out? (I think I'd change bulb, WIAT).

Earlier you said you replaced the alternator - with another
'new' unit? including the regulator? or did you put the 'old'
regulator into the 'new' alternator? Is alt'r. well-grounded?

Is there good continuity thru the path - Alt'r terminal D+, 14-pin
connector, pin 1; fuse panel terms. O8, Z1, Z6, H8 and cluster
term.11R? Good volts from bus 15 via term.H7 and cluster
term. 3R ?

G'luck.

 

Hi McCreel,
The bulb is not working when in the dash. I took the bulb out and checked it for continuity. It was OK and not blown.
The same with the resistor, I checked it for continuity while in place on the board, it was also OK.

The alternator that is in now is from my Euro. The alternator that was originally in the car when the problem started (which I thought was dead) was tested as OK. My assumtion is that the alternator is not the problem but the exciter circuit. This is because I have no positive - over 12v - readings and the volt meter on the dash is showing 10v. There is no light at the alternator warning.

This is where it gets over my head, so Doc is on his way to educate me. We will be testing all the points you mentioned above to find the short.

Thanks,
Roger

 

Rog,
Disclaimer :
Haven't gone thru the WSM's ...yet..., but I have a spare pod -complete-.
It's an oldermodel -mint condition, no sign of drying or cracking- came with the 85mph speedo.
Common sense says it's earlier than the 82'MY.
Point of contention;
Unless there was a significant change to the board -possible- other than relocation/addition of various warn lights I don't see from a wiring point of view where the alt warn light is necessary for exciter circuit.
The resistor is wired in like a jumper. So if the alt field only needs the resistance of the factory installed resistor to initiate the charge cycle there really is no need to have a Bulb draw juice then have the resistor kick it back to jump start the alternating cycle the resistor in the circuit -jumpered on the board- should serve that function as a stand alone.
Not saying this is Gospel but the circuit board is straight forward for the purpose of tracing.
If the alt is testing out good it has to be a wiring problem or as Jim suggests a board/board jumper problem.
Did you clean up the bulb holder grounds on the board?
Clean up the resistor/jumper board grounds and thin washers facing the board?

 

Your problem sounds like a continuity problem either at the plugs on the bottom of the Central Electric Panel, at the 14-pole connector near the jump start terminal, or on the harness that runs across the front of the engine. If there is a break in the circuit, you will get exactly the results that you are having.

Both the bulb and the resistor are necessary for the exciter circuit to function properly.

 

OK, OK, OK, I screwed up!!!!!

Doc came over and we started checking continuity between Pin 1 on the 12/14 pin connector and found that this was not good.
Doc asked me to check a connector on the central electric board and I found I had not reconnected the Z plug.
I had removed it to jump the factory alarm system and for some reason - alcohol, alzimers or drugs -forgotten to reconnect it.
This was the problem - sorry everyone for wasting your valuable time.

Car works great and the battery and alternator work as they should.

If there is a silver lining to this story it is the fact that I pulled the pod and will now replace it with the "Weissach" full leather pod I bought from Rixter.

Thanks and good night.

 

Roger... ('pologies to Doc) three words, Lotsa Cold Beer.

Glad life got simpler.

G'luck.

 

Alrighty, then!
Full leather Weissach pod???????????
Wally,
I thought you were selling the sHARk, moving to Europe ...
I'll look the Bulb/Resistor requirement up in the WSM.
I trust your response, just want to know WHY it's necessary.