voltage problem. need help - Ranger-Forums - The Ultimate Ford Ranger Resource


General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 07-29-2009
Demo1986's Avatar
Member
Thread Starter
 
Join Date: Feb 2009
Location: Long Beach, CA
Posts: 423
voltage problem. need help

everyone knows the voltage of a battery is 12 and when the truck is running it goes up to 13-15. with that being said when i turn my truck on the voltage drops to 11ish and it either fluctuates around 11 volts or sometime (actually right now) it starts to decrease to 9 volts then stalls. i got a new red top last month and a new alternator 30 minutes ago. the bearings were bad in the other one but was working fine. any idea what it could be guys? thx for ur help in advance.....
Reply With Quote
  #2  
Old 07-29-2009
bjohnson238's Avatar
Member
 
Join Date: Nov 2008
Location: Muncie, IN
Posts: 732
What was the voltage like before you replaced the alternator? And where did you get the new one from? Could be a junk alternator.
Reply With Quote
  #3  
Old 07-29-2009
Demo1986's Avatar
Member
Thread Starter
 
Join Date: Feb 2009
Location: Long Beach, CA
Posts: 423
same 11ish. kragen
Reply With Quote
  #4  
Old 07-29-2009
bjohnson238's Avatar
Member
 
Join Date: Nov 2008
Location: Muncie, IN
Posts: 732
but it never let the truck die? How are your battery cables?
Reply With Quote
  #5  
Old 07-29-2009
Demo1986's Avatar
Member
Thread Starter
 
Join Date: Feb 2009
Location: Long Beach, CA
Posts: 423
The new alt didn't change a thing! The cables r good. And I chked the fuse links and there good. Is there a fuse for the alt?
Reply With Quote
  #6  
Old 07-29-2009
White_Lightning's Avatar
Member
 
Join Date: Jul 2009
Location: farmland. connecticut
Posts: 44
im having the same issue pretty much, when i stop to an idle.. my voltage drops alot.... and im pretty sure my altinator and battery are good... but its worse when i turn my cabin fan on (ac or no ac)
Reply With Quote
  #7  
Old 07-29-2009
herm59's Avatar
Member
 
Join Date: Jun 2008
Location: Toms River, NJ
Posts: 1,694
I'd make sure all your wires are good. Also did you change out the pulley on the alternator?
Reply With Quote
  #8  
Old 07-29-2009
Demo1986's Avatar
Member
Thread Starter
 
Join Date: Feb 2009
Location: Long Beach, CA
Posts: 423
The pulley was new with the alt. When I disconnect the battery while the truck is running itstalls. Shouldn't it still run without the bat connected? I was thinking of this right now at work. I'm gonna chk to see if the alt is grounded.
Reply With Quote
  #9  
Old 07-29-2009
herm59's Avatar
Member
 
Join Date: Jun 2008
Location: Toms River, NJ
Posts: 1,694
Sometimes the pulley(s) on the new alternator are not the correct one(s).
Reply With Quote
  #10  
Old 07-29-2009
bjohnson238's Avatar
Member
 
Join Date: Nov 2008
Location: Muncie, IN
Posts: 732
Quote:
Originally Posted by Demo1986 View Post
The pulley was new with the alt. When I disconnect the battery while the truck is running itstalls. Shouldn't it still run without the bat connected? I was thinking of this right now at work. I'm gonna chk to see if the alt is grounded.
Absolutely not. An engine cannot run without a battery, unless its like a lawnmower, dirtbike, or other things like that. Newer vehicles from like the 70's? on up are computer controlled and have to have power to read sensors, open injectors, etc. And the alternator grounds at the mount. It doesn't have a ground cable to it.

Last edited by bjohnson238; 07-29-2009 at 11:41 PM.
Reply With Quote
  #11  
Old 07-30-2009
Member
 
Join Date: Aug 2008
Location: Taylor, Michigan
Posts: 96
You want to check all cables from the alternator to the battery. And check your battery out with a load test. I had a similar situation 2 years ago where I could charge the battery up and then start the engine and volts would be about 13.5+ while running. But after I shut it down the battery voltage rapidly dropped. I had MotroCraft battery less than a year old and I didn't think that would be the problem - but I took it out and went to where I had purchased it and they did a load test on it - and sure enough, it would not hold a charge!
Reply With Quote
  #12  
Old 08-14-2009
Scrambler82's Avatar
Old Guy Userů ltr
iTrader: (12)
 
Join Date: Jul 2009
Location: SoCal
Posts: 6,773
Grounds, wiring, belt, or maybe have the battery checked under load, could be a bad cell.
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
help with voltage meter lowlife Audio & Video Tech 3 09-23-2014 01:24 PM
Alternator Voltage and Voltage Drop at high RPM Derek_Z10 General Technical & Electrical 9 05-09-2014 10:55 PM
Need to know the pretensioner voltage/resistance? winks General Technical & Electrical 2 07-10-2008 07:31 AM
Electrical Problem - Voltage Drops pittpaulpittpaul General Technical & Electrical 6 04-26-2007 04:36 PM
constant voltage...... lifted97ranger General Technical & Electrical 13 05-13-2006 07:32 PM


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 07:14 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.