3.0 Charging System Issues Continue
 

I need a little help...

Previously on L.A. Law... I had a little issue with Pop, Smoke, Engine Dies (previous post) and got pointed toward the voltage regulator. I got the gen/VR tested and the Bosch shop replaced the VR. I reinstalled everything, and viola! It worked (for about 3 hours of driving time).

Today, after a spirited drive through the hills of the Pfalz with my digital volt meter stuck in the cigarette lighter,
it indicated that I wasn't charging (red light, steady 11.8v).

Upon further review... the volts are stuck pretty much at 11.8v. If I turn on the lights, they drop to 11.6v. If I turn the lights off, the dig voltmeter returns to 11.8v. If I rev the engine... no change. The fan belt looks good. The battery light and O2 light DO NOT come on during start or any other time... now. Earlier in the day, the battery light and O2 sensor light would come on briefly while I was sitting still idling. A little gas would up the volts and extinguish the lights. I looked at obvious fuses and didn't see anything amiss.

Removing the alternator/VR will be my second time in less than a month. I'm ready, but want to exhaust any other possibilities first. Thanks in advance for all the help.

BTW. I read "3.2 charging system" post which looks remarkably similar but I want to cover my bases. Thanks.

More info
 

At the suggestion of a good friend, I checked the continuity on the battery light and the O2 sensor light. Both appeared to be in order. But both definitely do not come on when the car is started. The oil light does turn on during start and goes out shortly there after. I recharged the battery... but it still appears there is no charging going on with the car.
Is there anything else I should check before pulling the alternator for a second time?:confused:

How old is your battery? A bad battery can cause similar symptoms.

The charge / OXS lights not coming on really gives me a headache, even as the bulbs check good. Anyone have an explanation of how that could be?

As I understand it, one side of the charging warning light goes to the battery, the other through the VR to ground. When no charging is taking place, the bulb gets 12V from the battery and ground through the VR and illuminates. When charging, the bulb sees 12V on both sides and doesn't light. So...no ground on the VR maybe?

The alternator was recently reinstalled- could a wire coming loose there cause no warning lights / no charging? Either the lamp to the VR or the ground between the VR and the body?

Anybody? Where's my ibuprofen?

Below is a link to the 1982 diagram (with OXY). See 5-1 and 5-2 for oil pressure light, oxy light and charge indicator. They all seem to be connected by a common line.

Pelican Parts - Porsche 911 Parts Listings & Diagrams

When you charge the battery up what voltage does it read on the cig lighter output?

Does you car exhibit symptoms of the battery getting weak from no charge? What is voltage at battery when the cig meter says 11.8?

MReid,
Not certain how old the battery is... but I'm having it checked at the Bosch shop along with the alternator and VR. It would be nice if it were something that simple. Thanks.
JHM

Bob,
Thanks for the diagrams.... hmm, its early today and I don't remember exactly what the voltage of the battery after recharge was... but it was "normal". I'm having it checked along with the alternator and the VR again.
Not certain what the symptoms of a weak battery would be...other than not starting. I haven't driven it a lot with the current issue so I haven't let the battery get too low.