red4kcsq

....It is a brand new alternator and has been on the car a week. I should also note that my last alternator would not fully charge until i reved it, but it only needed 2500rpm for it to kick in. The belt is tight and not slipping. I stuck a voltmeter to it and befor i reved it, it read 12.43 volts. After I reved it, it read 14.01 volts. Any ideas????? I read in a post from morgan that if the wires that run to the starter are crappy, it will cause a crappy running condition. The wires that run to the solenoid on my starter are exposed and corroded, but i dont see how that could cause a charging problem. Any ideas on that? Thanks!

AudiCGTSB

Did you replace it with a bosch one? B/C I have heard of a lot of problems with other manufacture's rebuilds.

BMWM5

You want one lead on the alternator + post and the other on the body of the alternator. It's possible you have corrsion somewhere in the system and the high rpms shake it enough to show you true voltage. Also check the connector to your dash lamp (it's working right?) aka "field" voltage with the key on not running, then see it drop to zero after starting. The heavy wire from the starter to the battery must not touch ground so check to see if the sheath is in good shape. are you near a shop that has an industive ampmeter? if so go there first (with a cold pack of good beer in hand) and check the current vs. voltage. If your starter cable (or any for that matter)is psudo-grounding, the alternator is trying it's best by giving mega current but can't maintain voltage untill the rpm is raised. Another possibility is the battery is completly dead, meaning it's so shot that the alternator doesn't really see a load thus won't go into charge mode.

Brian

BMWM5

My cost from with mechanic discount was a wopping $140 but it's the best one can get. Wel there is that Alfa Romero 120 amp drop in replacement...

85-4kq-girl

but I mentioned this to my dad because I remember him having the same issue with one of his cars. After he replaced his alternator, turns out that one cell in his battery was shot. He also mentioned to check all the grounds on the battery. They can get corrody and nasty, causing headaches. But change your starter wires so you don't have to learn the hard way like me!

--morgan

red4kcsq

I had the test leads to the positive and negative terminals of the battery. The battery is only 5 months old so i doubt i have a bad battery. As-far-as my interior voltage guage, I do have field voltage when i turn the ignition to on but it doesnt drop to zero after start-up, it just drops 1-2 bars on the guage. The battery light in my instrument cluster doesnt come on at all though. I dont think it has worked since i have had the car.

StormChaser404

Sounds like a bad regulator....

Katman

Even when swapped to a different car (that had no problems with *it's* alternator).

So that rules out the car wiring. But not the regulator. And I've ahd the alternator out, and even cleaned all the regulator contacts.

So, I'd say it's an odd function of the regulator maybe? But strange thing is, once revved up the first time, voltage is rock solid at any speed.

I've heard of other 4kq's with the same problem.

His story was that he started the car in the winter, and put the fan and rear defrost on (but forgot to give it that inital 'rev up'.)

He went back in the hose, waiting for the car to warm up. Came back to find the car not running, and the battery flat, as not enough charging action.