need an SME on electrical

[Ckanderson]

this ISNT supra related but i need help.

recently the benz has had a charging problem. it seems to happen once a month for like 20 min. ill be driving and a screen will display that says "charging problem" it will go away about 3-4 seconds later only to reappear at idle. its super annoying and would go away about 20 min later.

today it came on on my way to work, and it wouldent seem to go away. i drove to get a hair cut right now and the light is now on continuously. my capacitors are showing 11.8 volts at idle, without lights on, and doesnt change if i rev it. I am running dual batteries, and have no idea if that would effect anything, I'm assuming they are wired correctly since the car has 60k on it and the sterio has been in it almost the whole time. When I shut the car off the voltage shown is 12.3.

I assume it's not charging at all.

a rebuilt alternator is 2xx even at my price. a new regulator is only 30. I HATE electrical work, and have almost no tools to diagnose it.

where do I start?

 

[AJ'S 88NA]

this ISNT supra related but i need help.

recently the benz has had a charging problem. it seems to happen once a month for like 20 min. ill be driving and a screen will display that says "charging problem" it will go away about 3-4 seconds later only to reappear at idle. its super annoying and would go away about 20 min later.

today it came on on my way to work, and it wouldent seem to go away. i drove to get a hair cut right now and the light is now on continuously. my capacitors are showing 11.8 volts at idle, without lights on, and doesnt change if i rev it. I am running dual batteries, and have no idea if that would effect anything, I'm assuming they are wired correctly since the car has 60k on it and the sterio has been in it almost the whole time. When I shut the car off the voltage shown is 12.3.

I assume it's not charging at all.

a rebuilt alternator is 2xx even at my price. a new regulator is only 30. I HATE electrical work, and have almost no tools to diagnose it.

where do I start?

Just take it to AZ or someplace and have them check it and the batteries. How old are the batteries?

 

[Ckanderson]

waiting for a SME.

 

[jetjock]

Ja, you gotta love German engineering. Can't help much other than to say yeah, it doesn't seem to be charging. Putting a meter across the batteries at 2000 rpm would confirm that. Check fuses, eyeball the wiring, the usual stuff. I'd need to see a diagram before I could offer anything else. Frankly, after having to service a former girlfriend's Corrado for 5 years it'll be a cold day before I ever buy something from over there.

 

[Ckanderson]

ah... the guy I wanted to join the thread.

azzuming the wiring is ok (it should be being a 99 with 60k)

the regulator has brushes that get replaced with it...

Think that spending the 20 bucks or so for a new regulator would make sense?

 

[jetjock]

Sure. Go for it. Brushes and regulator. Beats the alternative.

 

[Ckanderson]

I thought you SME's could help me :sadwavey:

 

[p5150]

Yeah sounds like an alt problem to me - especially since you described how it died gradually. Thats usually how alternators go..... bit by bit until they just dont quite get it done anymore.

Sometimes if there is a minor defect contributing to the problem (corroded post, cable, bad battery, etc) it will appear to be fixed or will work fine for awhile but eventually the alt will give up the ghost and just not put out as much current anymore.

I think its all out of electrons :biglaugh:

 

[mkIIIman089]

I thought you SME's could help me :sadwavey:

It isn't MercMania...

 

[Twigger]

1. Get the batteries recharged with an external charger, and reinstall batteries, most autopart stores can load test and recharge batteries for free.
2. With a voltmeter check charging voltage at the batteries, then check at the alternator. If charging voltage is good and matching, chances are it could be the batteries. Bad or batteries low on charge will cause the alternator to have low output. If there is more than 1/10th of a volt difference between the readings on the batteries and the alternator then you may have a bad ground somewhere.
3. If batteries tested good and are fully charged and you still have low charging voltage, remove the alternator and take to an autopart store, or somehere that can bench test your alternator. Have them show you the results and go from there.

Usually with loads off your alternator should be putting out close to 14.4 volts.

 

[Doward]

You should see anywhere from 13-15v from your altenator, depending on load.

If you are reading 11.8v, then your altenator is not working.

If the wiring is good, then you have a problem with the voltage regulator, or the altenator.

Either rebuild the altenator, or get a new one.

Altenators are NOT hard to rebuild. It's basically a fancy metal disc inside a coil, with some bearings on both ends, and a little bit of electronics to provide a good clean signal, at a regulated voltage.