Electrical

[Lee]

I'm experiencing behavior of my alternator light that I've not seen before, and I'm curious if anyone out there has seen this.

All is well under normal driving and at idle - the light is out as it should be.

When the revs are between about 1000 and 2200 (such as slowing to a stop, or creeping around a parking lot), however, the light flickers, blinks, or stays on. When I blip the throttle it always goes out, and often when the engine settles into idle speed it goes out.

Curiously, my headlights also get brighter as the revs increase, so I'm thinking voltage regulator.

Any ideas?

Thanks folks,
Lee

[pwd72s]

Quite possibly the voltage regulator. Have you tested voltage? As Schmidt suggested here earlier, a cheap way to have a voltage meter as your are running is to buy a male cigarette lighter plug-in and then wire it to a cheap multi-meter. You can then place the meter on the passenger seat, read the voltage as you drive. Or, of course, as you change the revs. I experience voltage changes as I drive, but they remain well withing the safe range of between 13-14.4 volts. I consider that pretty normal with the original mechanical type voltage regulator. I worry more of an overcharge, voltage climbing to high...that can fry wiring. Too low because of regulator or alternator? Well, you won't run long...but you won't burn wiring either.

[roblav]

All of my early SWB cars experienced this behavior. The LWB cars went to higher capacity alternator. Maybe it is simply normal, or maybe the voltage regulator needs replaced.

[RandyWebb]

check the fan belt for both tightness and for glazing on the working surface - that's the easy thing that might cause this.

After that turns out ok - you will replace the VR as Paul said...

[Lee]

Thanks folks.

THe car in question is my 914-6, so a fan belt is not an easy thing!

Lee

[Lee]

Good idea for wiring the volt meter; I modified it a bit and used a wine cork. Here's the data folks:

When running at steady state (around 3k rpm), the voltage is around 15.5-16 volts. Idle is generally in the high 14s.

The curious thing is that as the revs come down, the voltage spikes at a bit above 16 volts. Also, with extended idle, the voltage will fluctuate between 14 and 16 volts, sometimes staying at 16. It's as these fluctuations occur that the light comes on (and sometimes stays on).

I don't have a lot of experience with this, but 16 sounds high, especially at idle. Sound like the voltage regulator?

Thanks again,
Lee

[pwd72s]

That is WAY too much ...16V is close to frying wiring! Yes! Try a new voltage regulator. There is a man here in the USA who can check V regulator settings, and adjust them if the unit is not completely shot. He also rebuilds the Bosch Capacitive Discharge units. Perhaps he has a counterpart in Germany? I wouldn't have a clue how to search, though. Perhaps Thorston Klein, who posts here, would know someone? (edit) Here is a link to the rebuilder here. Note that he has a "troubleshooting" section.
http://www.systemsc.com/

[Lee]

Thanks. By the way, I'm no longer living i Germany. I've returned to the US and am now living in Asheville, NC. Guess I need to update my profile...
Lee

[pwd72s]

Welcome back to the states...keep us posted on how this goes...

[NiceT]

Lee,
Sounds like you are narrowing it down but if you need some additional set of eyes to look at it I'm here in Asheville too. Not a great mechanic with regards to electrical problems but willing to help.

Daron

estrub@buncombe.main.nc.us