ROG100

After my no start with the 82 and the aparant fix of the infanous "green wire" I am still having problems.
Progress so far.
Battery was draining - 11V at the battery and jump post. No change when the car was rev'd.
Battery tested 100% at Autozone.
Alternator tested good at the alternator shop.
Cleaned all grounds apart from the one behind the pod.
Replaced alternator and got a reading of 13.8V at battery post.
Thought everything was fine.

Also deduced that the no start could have been a combination of low battery and no charge from the alternator which shuts down the EZK or so I read.

Tested again the next day and back to the same condition of 11v or less (depending on load).

Been reading the archives and deduce it is the exciter circuit that is giving me problems. I have not seen the alternator light come on at all. If the bulb has gone does this effect the circuit??

I will run the tests that Jim Moorhouse has provides just to recheck everything.
I will pull the pod and clean the grounds and have a look at the resistor and idiot bulb.

Anything else that I am missing?

Mark

When you initially turn on the key, ALL the warning lights - including the alt light - should come on.

rixter

Roger,
couple other things to check:
ground strap... may have breaks inside
did you clean the 14 pin connector?

ROG100

Mark,
Good point will go and check.

Rixter,
Cleaned the ground points and the main engine to frame strap looked OK but pretty dirty.
I will check it for continuity and put it in the sonic cleaner to be sure.

Thanks,
Roger

928FIXER

The ALT. light must come on when key is on and engine is not running.If not the alt. will not charge.

ROG100

Mark,
Just checked the light and it is not on when I turn the key.
All the others are - fuel, oil pressure etc.
Doe the bulb effect the circuit?
Roger

Mark

YES!! The bulb itself IS the exciter!

ROG100

928 Fixer,
So the bulb could be the culprit on it's own. Or is this just an indication that the resistor or the circuit is bad?

ROG100

Thanks guys,
Next I will pull the pod and report my findings.
Best,
Roger

ROG100

Where else could you find this high level of help and so quickly.
Rennlist rocks
Thanks

GR-JON

Rog...you have a PM.

docmirror

What is that little rectangular box just above the lamp on wiring diagram X28? I see the filament of the ALT bulb that supplies voltage to the D+ of the alt(field voltage) but I can't figure out what that little box is for? I thought a resistor would be the obvious choice so that the circuit would complete if the bulb failed, but that just makes too much sense.

Any ideas?

Doc

ROG100

Doc,
I am pretty sure it is a resistor from what I have read on Rennlist.
I will have the pod out in the next 30 mins and let you know what I find.
Roger

ROG100

OK,
Pulled the pod.
The alt light is good - I checked it for continuity.
The resistor has continuity.
Cleaned the pod grounds - they were pretty good anyway.
Started her up with the cluster in and no change.
Were to from here?
Thanks,
Roger

Joe Twill

If I remember...The 928's have a resister in parallel with the alternater light. The excitation current flows thru both. When the key is switched on battery power is supplied thru bus 15 to the light/resister to the alternator D+. If the light doesn't come on, it could be the bulb or anything in the circuit-- bad wiring, loose connectors (at fuse panel or pod).

Joe Twill
79 5sp