Wonky Alternator

Well, she couldn't kill me, so Gretchin did the next best thing: She broke. lol

Current condition is that the Voltage Gauge is reaching into the red, where it then bounces off of the regulator (Which can be heard from the alternator itself). Alternator is putting out too much power to try and overcome through lights, heater fan and stereo (Simply slows the bouncing effect). I know it may seem crazy, but I believe it may actually be the battery. I noticed when the alternator would disengage, the lights would dim. As it got worse, the engine would actually follow the bouncing too (Power would fall off when the alternator disengaged) and she seems to be having trouble turninig over. Just my own observations, however. Hopefully I'm wrong, otherwise this will be the... Fourth battery I'll have had to replace in just over two years.

The charging voltage should NEVER go over 14.4 volts for a liquid electrolyte lead-acid battery.  Regardless of the load on the alternator.  That regulator is going to cook your battery. Doesn't take long either.

It does sound like there is something drawing tons of current.  This is likely the root cause of the regulator dieing.  The whole case overheats and takes the diodes and/or the regulator with it.  I have a DC clamp meter here if you want to come over.   I can measure very high loads without having to disconnect any wires.

The Dawg

One thing I did not check at the track was that your battery cables were tight. A loose or damaged battery cable can create a resistance point tricking the alternator into charging wide open.  Also double check all your grounds. Make sure you have a good battery to chassis, battery to block and block to chassis ground.  I know the battery to chassis is a bit redundant, but I like to have it there.  Also as an extra point to help, I run an 8 gauge wire direct from the alternator charge stud to the power distribution block that is on the fender just below the main wiring harness connector. (main power distribution just rearward of the battery)  Again its redundant if the rest of your wiring is correct, but I am all about the fail safe when it comes to electrical.  You can never have too many grounds and I like to have alternatives if a main system starts to fail.

PM'd

Romeo wrote: Damien, I just got into the country, does tomorrow work for you?

I'm not at home so I can't send you a link, but there are some excellent websites describing how to check all components in an alternator. Heck, if you do a search here (or was it Pennock's?), I might've mentioned them in my thread describing my own alternator repair a year or so ago.

You need to be checking/replacing the brushes, diode-trio, rectifier, regulator, stator, field... I think that's it.

 

I am wondering if you have a dead short in the windings or something.  At this point, I would just say screw it, break down and buy a new one with a really good warranty.  Just make sure and buy the one for A/C as it is rated at about 1.5 X the output.  Bosch makes a good one, I put a Bosch one in Shirley's Fiero over 5 years ago and she drives it in rushour traffic 5 days a week and no problems from it at all.  Works perfect.

Romeo wrote: You replaced the stator? And what do you mean check the field? As for everything else, I replaced all that and the bearing...

Sorry, I got mixed up with a couple of the terms as I wasn't home when I last posted and was a little rushed. The items I was suggesting you check and replace as necessary were the brushes, diode trio, rectifier, regulator, stator, and rotor. Yes, I replaced the stator as it was toast.

Patrick in This thread wrote: Well, I finally fixed my alternator. With an automatic tranny and a V6, the alternator wasn't going to drop out the bottom (or out the top or out the side, etc). So I took out the four case bolts and "cracked" it in half while it was still mounted. I was then able to get both halves out the passenger side wheel well. Went to Edmonds Starters & Alternators, 532 East Broadway, and bought a set of brushes and a diode trio. Total cost - $5, no tax. Such a deal. Anyway, it turned out that not only was the diode trio shot, but so was the rectifier and the stator! I can't believe the alternator was producing any current at all, but I've been driving around this way for two months (with a dim volt light reminding me that something wasn't quite kosher). Luckily I had another alternator here that I could rob parts from and I used it's rectifier and stator/front case/pulley.  I reassembled the two halves while in place on the motor and started her up. Put a volt meter on the battery - 14.45 volts at idle. I'm a happy camper. Oh, and I put a heat shield on the alternator as well.

There are plenty of good websites with helpful information on alternators. Have a look Here, and Here, and Here at sites that I used.

Capt Fiero wrote: Bosch makes a good one...

If I remember correctly, it was a brand new looking Bosch alternator that Tristan picked up at Pick-a-Part.

 

Dawg wrote: Take your friend Damien's offer and go to his place where he can determine if the load is indeed external or internal to the alternator. I doubt there is an internal short but it is possible.  Were you not having this very problem before and this is why you purchased this used alternator in the first place??? If so, what are the odds that two alternators have the same internal short? The Dawg

Only one alternator. I replaced my first alternator because I wanted a higher output alternator as a pre-emptive move for the sound system, however, everything seemed to go downhill a few months back (On the way to autocross, as it were).

It should also be noted that every now and then, it will work normally for a little while, but after a sufficient jolt (Hard 1-2 shift, for example) it will go back to being screwy. I think I may just do a mix of what David and Patty said, I'll head to Edmunds Alternator and either get them to fix this one, or simply pick-up another from them.

Oh well. In either case I'll make this Edmund's Alternators' problem to deal with.

Yep yep. I know just how well the alternator is working - it cooked an 8-month old battery in no time flat.