TheSamba.com :: View topic

Fri Sep 24, 2004 4:59 am

Hi All

Driving home last night, not really pushing it, doing about 75, all of a sudden the van started juddering and came to a stop. Tried restarting, but there was no power, there was enough to keep the lights on, but wouldn't even turn over and I couldn't even hear the fuel pump ticking.
While I was waiting for the tow to come, the lights started getting dimmer, so I was wondering, what is the best way to test the alternator and wiring. Seemed strange that it had enough power to keep the lights on, but not enough to power the pump. Anyone have any idea's where to start looking! It's a porsche fan setup, does it have an internal regulator?

Fri Sep 24, 2004 6:29 am

Most autozone-type places can test your alternator, but you have to take it inside. If you have a test light, I'd make sure all the connections are good, something might have ceom loose. If you have a voltmeter, you can check the battery, alternator, etc, and see what's going on.

Fri Sep 24, 2004 7:49 am

A "Battery Factory" type place, AutoSmart/start whatever starter type place can also test your alternator In Car. They put a load on it while the engine is running to see how much it dips.

There are Battery testers that put a load on your battery to see if it dips. Good for testing the actual condition of your battery instead of how many volts it puts out. If its been at least 2 years since you've replaced your battery, and its not an Optima type...its time to replace it, regardless of what the warrenty says.

I think the Porsche alternators are 66amp, but some 911 fan conversions use a modified Rabbit alternator, so it would put out whatever Rabbit's are rated for.

When a alternator or battery craps out, usually the lights start to dim slightly and then your ignition starts to crap out. By that point there would be no way to turn the starter over if the engine dies. The coil needs about 9 Volts to keep firing. The starter needs at least 11 volts and at least 100 amps or so to turn over.

Check your wiring, in case anything came loose. If that doesn't fix it, Replace the battery, its cheaper than an alternator. IF that still doesn't fix it, take the alternator to a rebuilder and have it rebuilt.

Take care,
-Bobby