Trans program message now gone!!!

[KeithW '91 535i]

Popped a fresh loaner battery from the Zone in the car, then load tested...the charging system is putting out 30 amps. My battery check-out good. There is the problem. Now, is it the alternator or voltage regulator?? Looked up alternators and there is a 90amp and 115amp available. Any ideas how to determine what I should get? Thanks again!

[Javier]

(A/C, lights, window defogger, and every possible load) alternator top 30 amps, and voltage drops down (alternator sends what car demands, or less if damaged). If so, yes you have an alternator issue, and I would not blame the regulator straight. Are you looking to repair alternator, or will buy a replacement?

My car ETK have part numbers for 90A, 115A, and 140A. Do you have big power sucking audio system, heavy use of High beams? If so, I would go at least for 115A.

If you would attempt a repair, check stator, diode assembly, and brushes first, then rotor and finally regulator.

Now I would like to understand why the GM is working fine with low battery, or was it low before and now is OK?

Javier

[Kalevera]

Keith - I thought the 535's had a 140 amp? Javier knows all about this stuff. I think the key is to replace it with one of the same (115 or 140).

best, whit

[632 Regal]

Ryan went through the regulator and alternator scenereo and from what I got out of it is that they pretty much arent interchangeable from a mechanical standpoint. Ryan tends to be very anal about how he does things and after reading his ongoing alternater ordeal I would only replace mine with the same thing, not mess with changing out the regulators etc, get R done the first time and sleep good. As far as I know you need to get the original part number from the alternator and regulator to match it up correctly. Im sure you could upgrade to the big ass alternator if you need the extra output but what modifications I am not sure of, the brackets and stuff seem to all be the same at the online ETK deal though.

[Javier]

if you are going to repair your alternator, be sure to get parts for exactly the same unit (do not mix parts from 90A, 115A or 140A models). If you are going to replace it as a whole, you can select. Don't go lower than you already have, if you upgraded to 5 million watts stereo system, as some less aged (not younger than me! He He) guys, you may want to take the opportunity and upgrade capacity.

Javier

[KeithW '91 535i]

Sorry, I earlier posted wrong. I have the 115 amp and 140amp alternators available from Bosch warehouse. Aurozone sells the 90amp and 115amp units.
I am in favor of the higher output unit if it does not matter, leaving options for mods later. I do not know how to check just the voltage regulator and wondered how to do it. Javier, it was just a coincidence that the GM system was working at the time when the battery was run down. I thought that was funny.

[Javier]

proper tools, in general, if battery light is off, and alternator send GOOD current, but voltage is low, you have a regulator issue. For the rest of the scenarios, it is better to open the alternator and check components, if stator, diodes (all 9), brushes and rotor is OK, then again regulator is bad.

Javier

[ryan roopnarine]

i think the only way to be sure you know which alternator you have is to remove the voltage regulator (or if you can see it in place, that's fine), write down the model number on it, and call yves or patrick, or somebody with a bosch book, and have them check the output. you WILL save yourself a @ssload of trouble if you only need to change the regulator by doing this in advance. if you are changing it out as a unit, i'd still do the same and make sure that you aren't picking an undersized unit for your car.

[KeithW '91 535i]

proper tools, in general, if battery light is off, and alternator send GOOD current, but voltage is low, you have a regulator issue. For the rest of the scenarios, it is better to open the alternator and check components, if stator, diodes (all 9), brushes and rotor is OK, then again regulator is bad.

Javier
The battery light on the dash does Not come on. The load tester and charge tester measured 30 amps coming from the alternator. So, not getting good current. Car is feeding off the battery. Lasts around 2 days of normal driving.
I can visually check the voltage regulator brushes, but do not know how to check anything else.

[Bill R.]

sometimes the autozone ones are actually 140 amp when you open the box and look at them, and BAP usually has some good ones too...
The commutator on the alternator will have pretty deep grooves in it at that mileage and sometimes changing the regulator/brush package doesn't help
P.S. I still like color plus better..:)






The battery light on the dash does Not come on. The load tester and charge tester measured 30 amps coming from the alternator. So, not getting good current. Car is feeding off the battery. Lasts around 2 days of normal driving.
I can visually check the voltage regulator brushes, but do not know how to check anything else.

[KeithW '91 535i]

sometimes the autozone ones are actually 140 amp when you open the box and look at them, and BAP usually has some good ones too...
The commutator on the alternator will have pretty deep grooves in it at that mileage and sometimes changing the regulator/brush package doesn't help
P.S. I still like color plus better..:)
OK, OK. I know deep down that replacing that original alternator is the correct answer. I am off to Sedona for 2-3 days in the 7 and I will find a nice vortex there to ponder this on. Not! Thanks for the correct advice once again to all.

[Bill R.]

1
OK, OK. I know deep down that replacing that original alternator is the correct answer. I am off to Sedona for 2-3 days in the 7 and I will find a nice vortex there to ponder this on. Not! Thanks for the correct advice once again to all.

[ryan roopnarine]

bill, could you please enlighten us unwashed folks (and leave some help for ppl looking for info in the future) and give us an idea of how to identify the alternator output by sight? thanks.