Battery light when reving - Ranger-Forums - The Ultimate Ford Ranger Resource


General Ford Ranger Discussion General discussion of the Ford Ranger that does not fit in any other sub-forum.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 04-12-2009
davidw's Avatar
Member
Thread Starter
 
Join Date: Aug 2008
Location: Bow,WA
Posts: 207
Battery light when reving

when i rev pass 4000rpms my battery light comes on.......is this bad?
Reply With Quote
  #2  
Old 04-12-2009
Member
 
Join Date: Feb 2009
Location: Chelsea,AL
Posts: 562
Yea your trucks a goner..























JK prolly pullin too much juice cause your battery is going bad, could be altenator, but i think it would then stay on. IMO
Reply With Quote
  #3  
Old 04-12-2009
davidw's Avatar
Member
Thread Starter
 
Join Date: Aug 2008
Location: Bow,WA
Posts: 207
well its a new battery, and i only notice it lately when im reving high. but i think my battery has more cranking amp then the one i had before. prolly just producing more juice than i can use. when i get my brush guard and more lights it will use up more juice
Reply With Quote
  #4  
Old 04-12-2009
Member
 
Join Date: Feb 2009
Location: Chelsea,AL
Posts: 562
Oh yea, be careful when i put subs and light in it ruined my old battery
Reply With Quote
  #5  
Old 04-12-2009
davidw's Avatar
Member
Thread Starter
 
Join Date: Aug 2008
Location: Bow,WA
Posts: 207
thats why i got a new battery. sub and amp took the other one out.... i was splashing through tons of water on the road. maybe some got in there? everything worked totally fine
Reply With Quote
  #6  
Old 04-13-2009
Level I Supporter
 
Join Date: Aug 2006
Location: Durham, NC
Posts: 3,657
The brushes in your alternator are worn out. At high revs, they loose contact with the slip rings, and the output from the alternator stops. The brushes
are available separately, and aren't that hard to change.
Reply With Quote
  #7  
Old 04-15-2009
BlutoBodine's Avatar
Member
 
Join Date: Sep 2008
Location: Tulsa, OK
Posts: 543
Just guessing here, but..

overcharging = regulator
undercharging = brushes
normal voltage = excess diode ripple
Reply With Quote
  #8  
Old 04-15-2009
FireRanger's Avatar  
Join Date: May 2004
Location: CT
Posts: 0
I have to agree with Bob. The alternator is just worn out and can't handle the high RPM. Simple fix or just live with it.
Reply With Quote
  #9  
Old 04-15-2009
IN2 FX4's Avatar
Member
 
Join Date: Feb 2005
Location: Costa Mesa, CA
Posts: 855
Battery light at high rpm is s typical indication that the alternator is starting to go out. As Bob said; the brushes are probably worn.
Reply With Quote
  #10  
Old 04-15-2009
BlutoBodine's Avatar
Member
 
Join Date: Sep 2008
Location: Tulsa, OK
Posts: 543
Quote:
Originally Posted by FireRanger View Post
I have to agree with Bob. The alternator is just worn out and can't handle the high RPM. Simple fix or just live with it.
Good morning...

Could let AutoZone do a (free?) charging system analysis with a pocket tester while alternator is still installed, just to be safe. Undercharging at high rpm will probably just evolve into eventually discharging at a lower and lower rpm and leave the truck stranded, especially with AC season coming up. Overcharging could be worse if voltage gets too high - I've seen fried ECMs because of bad regulators. If battery smells bad or looks like it's been boilimg over I'd guess overcharging. If not, I'd agree with just being worn out.
Reply With Quote
  #11  
Old 04-16-2009
bmfmancini's Avatar
Member
 
Join Date: Mar 2009
Location: brampton ontario
Posts: 347
how bout starting the truck and disconnecting the battery wire if the truck shuts off you will know its the alternator
Reply With Quote
  #12  
Old 04-17-2009
Level I Supporter
 
Join Date: Aug 2006
Location: Durham, NC
Posts: 3,657
Quote:
Originally Posted by bmfmancini View Post
how bout starting the truck and disconnecting the battery wire if the truck shuts off you will know its the alternator
Absolutely NOT! You never want to disconnect a battery cable with the engine running. The di/dt can create huge voltage spikes that can destroy
expensive electronics, like the PCM, GEM, and even the alternator voltage regulator.
Reply With Quote
  #13  
Old 04-17-2009
bmfmancini's Avatar
Member
 
Join Date: Mar 2009
Location: brampton ontario
Posts: 347
ive seen it done b4 with no issues but ur right i just came to mind
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
2.5L Acting up, self reving and stalls while clutching Trumpy127 SOHC - 2.3L & 2.5L Lima Engines 5 06-27-2014 03:48 PM
HELP!! Reving Problem can't seem to fix. redbarradio General Ford Ranger Discussion 2 03-05-2012 08:14 AM
reving issues joe lucia 2.3L & 2.5L I4 Tech 3 09-24-2009 10:28 PM
Having some very strange reving issues?? Letha 2.3L & 2.5L I4 Tech 8 05-16-2007 10:08 AM
Reving 2002 Ford Ranger Rotors Ringhead General Technical & Electrical 36 10-17-2005 08:34 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 10:32 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.