Alternator Problem S5 Turbo

[Turbo II]

Last Friday, warning cluster lit up. Belt was fine but heard screeching sound when I revved it sometimes. Also under 1k rpms cluster lights went out, over it they came on. Drove it home removed alternator took it to Autozone and they said it was bad.

Took alternator to local shop that rebuilds them, they check it and said it was bad and I left it with them to rebuild. Picked it up today, installed it and it worked fine for about 5 mins and then lit up the warning cluster and showing up to 18V output at times.

Battery reads fine, car runs great, no squealing this time from the belt (was it trying to lock up before?), just the same over/under 1k scenario and putting out way to much voltage. It was putting out anywhere from 13 to a little over 14 volts before it flipped out.

Is it possible they I got a bad rebuild or is there another electrical problem I should look for?

[Turbo II]

Decided since I left the windows open and the hood up while I was online searching for answers I'd better close it up. So I cranked it up and it worked fine for 5 mins again except I noticed this time since the parking lights were on so I could see the dash that around 3500 rpms or so the two lights on the warning cluster (open door and parking brake on) were fluctuating some (brighter then dimmer) as well as the lights on the dash and doors. Other than that everything was fine, anywhere from 13 to 14 volts depending on the revs until it decided to freak out again and start putting out 17 volts and the warning cluster came back on. Guess I'll be pulling it back off tomorrow morning.

[FC Zach]

I would say that they used a defective part in the rebuild, it's not uncommon with and reman. Just have it retested.

[Turbo II]

Someone mentioned that the voltage regulator is inside these alternators. May have to ask them about that but yeah I'll be running it back by there and have them check it out.

[FC Zach]

Yes, it's an internal regulator.

[RETed]

Go back to the rebuild shop and ream them a new one.
Ask for your money back.
That faulty alternator could have (or did) damage your electrical system.

Go find another (better) shop or go to the Mazda dealer for a reman one.


-Ted

[Turbo II]

Took it off this morning and went back to the shop that rebuilt it, of course they were closed. So I went in AutoZone down the street to have them check it and it passed, twice. Told him it seems to take 5 mins or so before it starts screwing up and he said they could test it on the car to get a better idea. I'm not to thrilled about driving it around with this problem even though the store is just 5 miles from the house and not sure what they could find out. Any chance it could be the B or S/L connectors going to the alternator or something else on the car?

Someone mentioned just running a temporary wire from the S terminal to the battery, forget the L completely, didn't mention the the B connection but I imagine leave it hooked up since it's hot also. Said once it bumped up to about 3000 rpms it should kick start the alternator into working and run fine if it's a problem with the connector.

(Edit)
So with nothing else to do this afternoon I put it back on and it did the same thing again. Worked fine for a couple of mins and then started putting out 17-18 volts.

[JL1RX7]

Sounds like the voltage regulator is shot. Best bet would be get a new one. Unless that shop can fix the diodes.

[Turbo II]

Went back to the shop that rebuilt it and they were extremely cool about the situation. They let me go into the shop while they tested it on their rather large old school machine (compared to AutoZone's computerized one that fits on a counter top) and it freaked out on it immediately. Apparently the new voltage regulator they used was bad is what they said but they will also go over everything else again just to make sure. They said it will be ready tomorrow afternoon.

[My5ABaby]

I've had that happen a couple times. On the plus side my headlights were like HID bright...

[Turbo II]

Anyway, got it back from them the next day, put it on and I have had correct voltage readings since.