Seems my altenator gauge won't register. Just changed the voltage regulator and no change. Gauge light works. Anyone have some suggestions on what I can check before I buy another altenator?

 

Maybe I'm missing something, but is your alternator putting out ~13.5v or better - as measured with a DVM? ( and is the battery at ~12.6v?) If you have these values, the alt/bat combo is OK.
The pod ammeter is an unreliable test of an alternator, or battery, and may itself be dead.

 

Tim...Are you saying that the alt. light is on when the car is running? BTW what MY is your 928?...tnx

 

The altenator gauge light works so I know the circuit is somewhat complete. Battery seems to drain when sitting for a few days. Now it is running off the battery. The needle on the gauge never moves. I changed the voltage regulator with no results. Sometimes when the battery is dead and I charge it for a few minutes, it acts like it is a new battery. The the car runs for a few minutes and slowly dies.

 

The ammeter should at least respond to battery voltage. Does the 'red' light go out when the engine is running? When the eng. is running, what is the voltage at the underhood tap, or at the battery? As noted seperately, you need some voltage measurements to cut thru this: if you haven't got one, a pretty usable digital volt meter (DVM) can be picked up for ~$15 - will save you a ton!
You'll likely be pulling the alternator again: did fresh brushes go in with the new regulator? If you can, get the alternator on a test bench prior to installation - if they don't put out ~90 amps under load, it's not ready to go back in.
Then, there's the continuity checks, etc. - Yeah, electrical is the proverbial pain in the ....., but the charging circuit isn't too bad, and will give you the experience needed for the next 928 screw-up!

 

I"m dropping off the altenator to a very reliable auto electric place here in town. They can bench test it for free. If it is bad they rebuild them for about half the cost of buying a rebuilt over the internet. Thanks for input and we will see what happens after Monday.

 

Tim...It is very important to have the field voltage. The alternator will not produce voltage without it. If you go into the archives you will find all kinds of info with regards to the charging circuit. Wally has a great explanation of the charging circuit in there. There are a few checks you can perform prior to dismantling and there is a test jig you can make to test your circuit..
Good luck I too have had those issues....

 

I've been searching for Wally's charging system information but have had no luck. If someone out there knows where it is please send to my email. Thanks.

 

Tim...Go to search mode and type in charging problem and search in 928 forum. Look in 2nd page you will see a topic with my credentials...Bill 84 928s...you will find Wally's write up in there ....I still have problems occasionally...good luck .....