reasons for alternators to not charge the system

Thread Tools
 
Search this Thread
 
  #1  
Old 04-24-2009, 12:56 AM
mtn_maro's Avatar
2nd Gear member
Thread Starter
Join Date: Sep 2008
Location: Montclair CA
Posts: 322
Default reasons for alternators to not charge the system

my alternator isnt charging my car. i dont want to just pull it off and take it to autozone or w/e to get it tested. would prefer to try things out first. so what reasons would there be?
 
  #2  
Old 04-24-2009, 01:58 AM
Saint_Ali's Avatar
Overdrive Member
Join Date: Jun 2006
Location: Las Vegas
Posts: 3,170
Default

are you sure its not the battery ? if the alternator isnt charging your car,most likely something inside has gone bad
 
  #3  
Old 04-24-2009, 02:02 AM
Camaro 69's Avatar
Senior Moderator
January 2010 ROTM Winner
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
Default

If you have a test meter, you should be getting around 14 volts at the large red wire stud connection on the back of the alternator. One thing that could be bad (and is the likely culprit) is the internal voltage regulator. Look at the back, and through some slots in the case you should see a shiny metal which is the back of the regulator. The "other" wires that plug into the alternator, are actually plugging right into the regulator. Take a small screwdriver, touch it to the back of the regulator while also touching the screwdriver to the alternator case. That grounds the regulator and puts it into "full mode". If your alternator starts to whine from the load, and your voltage spikes up, then it's your regulator that's bad. It's about a $15 part, and it's up to you if you think you can rebuild the alternator. I've done quite a few, it's not that hard to do.
 
  #4  
Old 04-24-2009, 02:23 AM
mtn_maro's Avatar
2nd Gear member
Thread Starter
Join Date: Sep 2008
Location: Montclair CA
Posts: 322
Default

Originally Posted by Camaro 69
If you have a test meter, you should be getting around 14 volts at the large red wire stud connection on the back of the alternator. One thing that could be bad (and is the likely culprit) is the internal voltage regulator. Look at the back, and through some slots in the case you should see a shiny metal which is the back of the regulator. The "other" wires that plug into the alternator, are actually plugging right into the regulator. Take a small screwdriver, touch it to the back of the regulator while also touching the screwdriver to the alternator case. That grounds the regulator and puts it into "full mode". If your alternator starts to whine from the load, and your voltage spikes up, then it's your regulator that's bad. It's about a $15 part, and it's up to you if you think you can rebuild the alternator. I've done quite a few, it's not that hard to do.
ok. ill check all of my connections first then ill try that. if that doesnt work ill pull it and bring it into kragen or autozone and get it tested
 
  #5  
Old 04-24-2009, 02:24 AM
mtn_maro's Avatar
2nd Gear member
Thread Starter
Join Date: Sep 2008
Location: Montclair CA
Posts: 322
Default

oh yeah. thank you for your help. any more suggestions wouldnt hurt
 
  #6  
Old 04-24-2009, 06:34 AM
blackz87's Avatar
4th Gear Member
Join Date: Mar 2006
Location: Florida
Posts: 2,430
Default

Alternators are know to fail....Duh
 
  #7  
Old 04-24-2009, 12:31 PM
Camaro 69's Avatar
Senior Moderator
January 2010 ROTM Winner
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
Default

Originally Posted by blackz87
Alternators are know to fail....Duh
Haa, haa...funny one!
This would be the simplified answer to the question: An alternator stops charging when something with it goes bad.
 
  #8  
Old 04-24-2009, 03:28 PM
microkid's Avatar
March 2011 ROTM
Technical User
ROTM Winner's Club
Join Date: Oct 2006
Location: Biglerville, PA
Posts: 2,615
Default

dont forget to inspect the wires and the cable connections. ive seen people spend $200 for a new alternator just to find out it was a $10 wire that was corroded inside the insulation
 
  #9  
Old 04-24-2009, 03:36 PM
mtn_maro's Avatar
2nd Gear member
Thread Starter
Join Date: Sep 2008
Location: Montclair CA
Posts: 322
Default

Originally Posted by microkid
dont forget to inspect the wires and the cable connections. ive seen people spend $200 for a new alternator just to find out it was a $10 wire that was corroded inside the insulation
that was the first thing i checked. took it to autozone and kragen and got it checked. ended up being bad. so im gonna replace it
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
deez28
67-69 General
1
10-18-2013 05:38 AM
94z
93-02 General
18
07-30-2008 08:41 PM
damnyankee36
82-92 V8 Tech
0
05-16-2008 03:07 PM
Kblerelfs
70-81 General
9
11-16-2006 10:55 PM



Quick Reply: reasons for alternators to not charge the system



All times are GMT -5. The time now is 05:48 AM.