alternator question

Ok, Brute, you got me convinced. I removed my pretty little chrome alternator last night and opened it up.
I see a white plastic part with two prongs (male side of plug in.) I also see what looks like a capacitor? There is also a strip with vented ribs on it.
I am guessing that the white plastic part is the regulator. AM I right. If so, can I just pick up the normal one and switch the parts out.
The auto electric place wants $40 to do it, so it can't be too hard.
I have done a number of EFI wiring harness conversions and tons of re-wires on different stuff. I can't imagine this being too difficult.

Justice

 

whoaaaa, justice:

might have gotton ahead of yourself a bit,, yes you can change some things around but first let me ask you these questions,

just cut and paste them in with you answers so i dont get lost in the mix.

1. did you have the alternator tested?

2. if you had it tested and it worked ok, then did you check to see what the battery was actually getting with a hand held voltameter?

3. at idle how much showing at the battery?

4. at fast idle or around 2000 rpm engine speed how much at the battery?


the reason i am asking is , there are all sorts of other tests to make before you open the case on your alternator.

one final question, did this alternator ever do the job for you?

in any case message me and i will send you my phone number so i can talk to you re: your alternator.

bob

 

1. did you have the alternator tested?

2. if you had it tested and it worked ok, then did you check to see what the battery was actually getting with a hand held voltameter?

3. at idle how much showing at the battery?

4. at fast idle or around 2000 rpm engine speed how much at the battery?


I'll make it simple: No charge at idle ZERO, NADA

Above 1500 RPMS it charges just fine. The problem isn't how much charge I am getting. The problem is keeping the alternator excited. It does the job just fine as long as it stays excited.

I am going by a properly wired voltmeter in my dash.
It won't matter how much it charges if it doesn't excite, right??

Thanks,

Justice

 

Brute,

I am sorry. I meant to go back an answer the questions in my last post and forgot.
The alternator works fine except at RPM's below 1500.


1. did you have the alternator tested? NO

2. if you had it tested and it worked ok, then did you check to see what the battery was actually getting with a hand held voltameter? N/A

3. at idle how much showing at the battery? 11 volts

4. at fast idle or around 2000 rpm engine speed how much at the battery? 13.5 volts


Justice

 

i dont mean to beat a dead horse but i have to ask, how do you know what the battery is receiving if you dont have a hand held multimeter? i am not trying to be difficult but i dont necessarily trust the dash guage for a couple of reasons.

1. the guage can be defective or inaccurate, possible

2. the guage could be connected to something that has a voltage drop, possible.

3. the guage may not be grounded well to the dash, or the dash not grounded well to the body, or the body to the frame and engine,, all of which could mean an inaccurate reading.

correct me if i am wrong but i don't remember if you said that the battery is going down and failing to start the engine because of low/no charging, or just that you are seeing a low voltage on the dash guage and have become concerned.

i am asking all these questions to rule out all possibilities that may or may not be your problem.. before you go and spend money on parts...

as an example i have rescued many good parts from the dumpster that were functionally perfect but were poorly diagnosed,, the customer bought parts he didnt need, and i got his old part later having found it pitched.. i got 3, airresearch T04-B turbo's that warranty refused to pay the dealer on because their was nothing wrong with them. all had less than 1500 miles on them,, they were replaced because of low power complaints, in the dumpster they went, complete with styro packaging, and into my waiting arms they came..

Alternators are no different..

i know this is getting tedious for you, but you are with the alternator, and i am trying to help with something i havent troubleshot, so i guess i have to ask what appear to be redundant questions.

i guess if you can answer these last couple of questions i can narrow this down now.

btw, yes the regulator is under the brush holder, and has the 2 male spade terminals sticking out of it.

trying to help...

bob

 

Brut,

I don't mind answering. Heck, you are tryin' to lend a hand.

"correct me if i am wrong but i don't remember if you said that the battery is going down and failing to start the engine because of low/no charging, or just that you are seeing a low voltage on the dash guage and have become concerned."

The reason I initially got concerned was based on my voltmeter indication. I checked it with a voltmeter at the battery and at the alternator. Both indications agreed with the dash guage. The battery had also gone down and failed to start.
The alternator charges great when it is excited. It just won't stay excited below 1500 rpms.
As long as I drive above 1500 RPMs for a little while I am fine. However, this isn't practical when I go on short runs close to home or longer drives through town.
I have no problem with the output in terms of amps. I just need it to excite at lower rpms.

Justice

 

I have the regulator sitting on my desk here at work. I was going to get a OEM style from our garage mechanic.
I figure I would throw that in there when I get home and see how it works.It only take about 10 minutes to assemble and install the alternator.

However, I am interested to see what you have to say. It sounds like you have messed with this kind of thing a good bit.

Jared

 

excellent tech stuff here brutus!if anyone is interested,there is also some neat tech info,(such as one wire vs. three wire alternators,and why g.m.designed what they did),at madelectrical.com,(didn't know how to link it). keep layin' it on brutus,i'm soakin' up as much as i can!
tech-o-matic?

 

justice:

go ahead and stick in a new regulator, they arent that expensive and you may as well give it a try while you have it apart.

after you get it together, you might take it in to the electrical shop and have it tested, have them do an output test at low as well as high rpm to see how it is operating.

based on what you are relating to me, there is no reason that the alternator once excited should kick out and become de-energised, unless there is a fault with the regulator, or possibly a faulty leg on the diode trio feeding the regulator.

i guess while you have the thing apart, do check the rectifier bridge, and the diode trio. Testing them requires only a continuity tested or a battery powered test light, and is easy enough to do, but hard to explain without pictures.

but do check them out, if you have trouble let me know.

bob

 

Brut,

Thanks a lot for all your help!!!
The regulator and the rotor were bad. This is according to the local auto electric shop. He said the rotor probably killed the regulator. (smoke up my butt?????)
Anyway, it charges great now. It excites as soon as the car starts and stays excited the whole time I am driving, fast or slow.
I drove the car to a local show last night with no problems.

Thanks again for all your help.

Justice