kyle944

I replaced the Voltage Regulator in my '87 944 yesterday and I still have low voltage. I went to the auto parts store to have my battery voltage tested and the car nearly died getting there. Revving the engine doesn't make any difference. I'm fairly certain my alternator is the problem and it's not properly charging the battery. Anyone had similar issues?

Thanks!

-Kyle

StickShift

Check the voltage at the battery with a meter with the car running. If you see less than 13.5 volts, it is the alternator. Instead of replacing the whole alternator, you can swap out the brushes for about twenty bucks.

f1rocks

Or swap it for a lifetime warranty one at an Autozone for around $110.

mytrplseven

How's the battery itself? It's not unusual to have this issue when putting a VR on an alternator where the rotor part of the unit is worn or badly grooved so the brushes on the VR don't get good contact.

kyle944

The battery is relatively new (3 months old). As I said, the new voltage regulator did nothing for the low voltage problem. I charged the battery up to 11.5 volts and it still runs at barely above 10 volts. It's fine at idle, but the needle drops under input from the throttle. Also, the "!" light is dimly lit.

mytrplseven

Is the alternator belt tight? If they slip, they can cause marginal alternator performance. Also the 12v
exciter wire (light blue) provides exciter voltage to the alternator. Even if that wasn't available, when the car is revved above 2500 rpm or so, the voltage output would jump to around 13.5 to 14 volts and stay there. Sounds like it's time to have the alternator bench checked or simply replaced outright.
Still love my shifter, Kyle.

use2windsurf

I went through the same thing. if you pull of the regulator you installed, you will probably see the brushes are grooved again. I found a good used alternator on ebay for $65 shipped and it has worked great evr since.