Alternater Issues, Can't seem to figure it out..... Options

[martinef1963]

Hey Gurus - just wanted to see if I can get some ideas on how to isolate a little apternator issues.

1st symptoms dead battery (bought new one, two to be exact) R&R.

Battery kept running down, so I put a voltage meter to test the battery/charging system. It was spiking all over the place - up to 19 volts.

Bought two voltage regulators and R&R the old one. Still have spiking problems, so

Removed the alternator that I just bought (Bosch) and had it tested @ the auto parts store - runs perfect - 14 volts.

Did I mention that my alterator wires are new - from Bowlsby.

Now I've put it back toegether - it's running as I type, but the idiot light is still on!! (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

Does anyone have any ideas on what could be causing the battery from going dead, and the voltage spiking all over the place? It is an electrical gremlin, but I can't find that sucker.

i've attached a picture of my girl -

thanks

[Dave_Darling]

QUOTE (martinef1963 @ Jul 15 2005, 01:13 PM)

PS - how do you polorize an altenator?

You don't--not one of ours, at least. IIRC, you polarize a generator, like you'd find on a really old Bug or 356. You might need to polarize a "self-exciting" alternator as well, I'm not sure, but that does not apply to ours.

If the voltage is spiking all over the place including very high, the regulator is not regulating worth a damn. Either your new regulator(s) are bad, or the wiring to the alternator is bad, or the relay board is. It might be possible that there is something inside the new alt that is intermittently shorting as well.

Sometimes new parts fail as they are installed, or immediately upon first use. It would be a big chunk of bad luck to have it happen to two VRs in a row, but not completley unheard of. And I know Jeff is as careful as possible when he builds up his harnesses, but it is possible that something happened to it at some point.

I don't know how to narrow this down further, other than by parts swapping which gets rather expensive. You might be able to check the wiring harness to see if there is any kind of cross-connection between the wires... That's the only test I can think of off the top of my head.

--DD