Well a couple weeks ago I replaced my voltage regulator on the back of the alternator. It had improved consistent voltage output. Or so I thought. Yesterday the car had a difficult turnover incident. And when fired up, the rear defrost switch was flashing! Voltage had to be low. It drove fine the rest of the day though for the most part with things either working or running low voltage. Very intermit ant.

Anyway, after some voltage readings something was not right. So I ordered the AL129X Audi (or Saab?) alternator everyone seems to recommend. The 110 amp upgrade is certainly needed over the stock 60 amp anyway and it was something I was planning for this summer.

The unit is not the same. I did re-use the original pulley, fan, spacers, etc. So no belt alignment issues. Besides, the new one had non of that. But the electrodes are on the opposite location. On the old they are towards the top. With the new, at bottom. That is a problem with my 91. When swung down the electrode comes into contact with something coming off of the block. I am not sure what the setup is, but its a valve that touches. I had to really crank down on the belt to prevent contact. The stock cables were no issue though, plenty of length. But I can not swing the alt all the way down. I will always have to install longer than stock sized belts.

Things seem fine now. I cleaned all the metal on metal contact points and bolts. I also installed a second ground strap from alternator to body frame.

With the old alt at idle it read 13.XX and would NOT increase under increased RPM. Back when I installed the new reg, I was getting about 14.5. So something had degraded since then. And voltage should go up with increased engine speed. With the new I get about 14.1 at idle. With everything turned on it drops, but with increased engine speed voltage quickly recovers as it should.

Not a hard job to do. Now I have a very slightly used Bosch regulator if anyone is interested. From what I read it will not be of any use on a 110 amp alternator.

__________________
1991 560 SEL / 185k miles
1992 750il / 17k miles - project car