E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 03-31-2013, 02:03 AM   #1
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
Question super low output amps on alternator, super confused...

I have a 2001 BMW 325ci, I have replaced the battery and replaced the alternator 3 times and I'm still getting the same issue... It's a valeo alternator that pushes out 120 amps but each alternator I put on is only pushing out 30 amps. I can not figure out this problem... Can someone please give me a suggestion.
Drayko is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 03-31-2013, 09:14 AM   #2
jgold47
Registered User
 
Join Date: Sep 2010
Location: Imported from Detroit
Posts: 1,262
My Ride: 2004 X5 3.0
How are you measuring Amprage output? What else is going on that you are testing this?
__________________
Religion, Politics, and which oil is the best to use. Three things never to be discussed in polite company...

my about me link
http://forum.e46fanatics.com/showthread.php?t=791566

jgold47 is offline   Reply With Quote
Old 03-31-2013, 09:26 AM   #3
bernie21614
Registered User
 
Join Date: Apr 2010
Location: Glendale, AZ
Posts: 326
My Ride: 01 330i
It's rated for 120 amps, but will only put out what it needs up to that amount. If your turning everything on on your vehicle and that's your output then your alternater is fine
bernie21614 is offline   Reply With Quote
Old 03-31-2013, 10:05 AM   #4
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
I went to AutoZone and had them test it and it comes up low output. I had it tested because everytime I roll the window or do anything electrical I loose massive power.
Drayko is offline   Reply With Quote
Old 03-31-2013, 11:56 AM   #5
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
Check your grounds. Is it putting out 14V with the engine running?
__________________
lcoleman is offline   Reply With Quote
Old 03-31-2013, 01:22 PM   #6
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
It's putting out all the correct voltage just not the right amperage
Drayko is offline   Reply With Quote
Old 03-31-2013, 02:15 PM   #7
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
If you have replaced 3 alternators with the same results, it's a safe bet that the alternator itself isn't the issue.

Also, if you "loose massive power" with accessories on (headlights and rear defroster), then you don't have 14V all the time.
__________________
lcoleman is offline   Reply With Quote
Old 03-31-2013, 02:49 PM   #8
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
Well I've come to the conclusion it's not the alternator lol. I have 14 volts at all times, I have a voltage gauge, it drops to 12 volts anytime I put my headlights on, drop my top, or use any kind of electronics in the car
Drayko is offline   Reply With Quote
Old 03-31-2013, 02:51 PM   #9
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
I basically have low amperage and that's it, power is being drawn from somewhere and I dont know where? Or what's causing this
Drayko is offline   Reply With Quote
Old 03-31-2013, 02:53 PM   #10
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
I disconnected my stereo system thinking that was the problem but it's not, I can't even turn my subs on... When bass hits my car shuts off... Lol
Drayko is offline   Reply With Quote
Old 03-31-2013, 03:05 PM   #11
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
Quote:
Originally Posted by lcoleman View Post
Check your grounds.
...and the connections on the alternator plug.
__________________
lcoleman is offline   Reply With Quote
Old 03-31-2013, 04:16 PM   #12
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
Everything on or around the alternator is secure
Drayko is offline   Reply With Quote
Old 03-31-2013, 05:51 PM   #13
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
Neither of the main grounds are near the alternator. Battery neg cable and the main engine ground on the passenger side engine mount. Also, make sure the battery terminals fit tightly.
__________________

Last edited by lcoleman; 03-31-2013 at 05:51 PM.
lcoleman is offline   Reply With Quote
Old 03-31-2013, 06:02 PM   #14
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
Well I know the ground next to the battery and next to the computer compartment area are tight. But the negative terminal is a lil loose but I can't loosen it, it looks as if it was soldiered together or like it got really hot and the nut is fused to it and won't turn
Drayko is offline   Reply With Quote
Old 03-31-2013, 06:05 PM   #15
Stinger9
Registered User
 
Join Date: Sep 2011
Location: New York
Posts: 8,011
My Ride: '04 330Ci
You need to eliminate a possible high resistance connection. Especially on a car your age.
Check the clean & tight condition where the two cables connect at the drug bin. Also at the starter motor.
And the engine ground strap under the car.



give us a much better description of this statement: But the negative terminal is a lil loose but I can't loosen it, it looks as if it was soldiered together or like it got really hot and the nut is fused to it and won't turn
This sets off an alert that something may be wrong here. Take some good pics for us!

Last edited by Stinger9; 05-08-2014 at 06:39 PM.
Stinger9 is offline   Reply With Quote
Old 03-31-2013, 06:05 PM   #16
Drayko
Registered User
 
Join Date: Mar 2013
Location: MO
Posts: 62
My Ride: 2001 BMW 325ci
Also does it matter if I have my amp grounded to the car body or directly to my battery?
Drayko is offline   Reply With Quote
Old 03-31-2013, 06:12 PM   #17
bernie21614
Registered User
 
Join Date: Apr 2010
Location: Glendale, AZ
Posts: 326
My Ride: 01 330i
You can't always trust the autozone guys to use the equipment correctly, I remember seeing a TSB about weird power draw with certain accessories and it called for some module to be replaced can't remember the details on it. Are the alternators your getting new? Double check that everything is connected correctly and is secure also check the resistance of the cable that goes to from batter to alternator there could be something wrong with it.
bernie21614 is offline   Reply With Quote
Old 03-31-2013, 07:01 PM   #18
Stinger9
Registered User
 
Join Date: Sep 2011
Location: New York
Posts: 8,011
My Ride: '04 330Ci
Quote:
Originally Posted by Drayko View Post
Also does it matter if I have my amp grounded to the car body or directly to my battery?
No doesn't make a difference.
If a high resistance connection is your problem, it is not any piece of equipment in your car drawing too much current. It is about your electrical system not supplying enough voltage because it is losing a few volts across a high resistance connection.
Get the connections tested that I suggested so we can get this out of the way and then move onto the next step.
Stinger9 is offline   Reply With Quote
Old 03-31-2013, 07:02 PM   #19
lcoleman
Registered User
 
Join Date: Mar 2007
Location: the barnyard
Posts: 2,458
My Ride: '79 Massey Ferguson
Quote:
Originally Posted by Drayko View Post
But the negative terminal is a lil loose but I can't loosen it, it looks as if it was soldiered together or like it got really hot and the nut is fused to it and won't turn
http://www.ecstuning.com/Search/Terminal/ES163623/

Edit: Directly to the battery is better.
__________________

Last edited by lcoleman; 03-31-2013 at 07:02 PM.
lcoleman is offline   Reply With Quote
Old 03-31-2013, 07:06 PM   #20
Stinger9
Registered User
 
Join Date: Sep 2011
Location: New York
Posts: 8,011
My Ride: '04 330Ci
Quote:
Originally Posted by lcoleman View Post
Neither of the main grounds are near the alternator.
There are more than just main grounds. And technically there is a main ground near the alternator. The case of the alternator is grounded to the engine. But we don't consider testing this because it can't go wrong with the massive amount of metal to metal tightened with the mounting bolts.
Stinger9 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON





All times are GMT -5. The time now is 08:32 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use