5.0L (1979-1995) Mustang Technical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.

battery or alt

Thread Tools
 
Search this Thread
 
Old 11-13-2006, 02:10 AM
  #1  
stang91
Thread Starter
 
stang91's Avatar
 
Join Date: Oct 2006
Posts: 22
Default battery or alt

hey guys I m having a problem I dont know if is the battery or my alt but when I turn my car on and let it set my voltage gauge goes down and when I push the gas it goes up again and if I have the door open for 5 min my car dont want to start someone please
stang91 is offline  
Old 11-13-2006, 02:12 AM
  #2  
mattdel
6th Gear Member
 
mattdel's Avatar
 
Join Date: Nov 2006
Location: Spfld, MA
Posts: 9,240
Default RE: battery or alt

your alt is discharging and draining the battery in the process. it might have even killed some of the cells. replace the alt, and see what happens. if you still have starting issues, you have dead cells from the alt and need to replace the battery.
mattdel is offline  
Old 11-13-2006, 02:15 AM
  #3  
stang91
Thread Starter
 
stang91's Avatar
 
Join Date: Oct 2006
Posts: 22
Default RE: battery or alt

I do that and thanks
stang91 is offline  
Old 11-13-2006, 02:18 AM
  #4  
settled4automatic
3rd Gear Member
 
settled4automatic's Avatar
 
Join Date: Jun 2004
Location:
Posts: 613
Default RE: battery or alt

whooooooooa, don't just go replacing things!!!! that's BAD.

batteries are EXPENSIVE, alternators are MOOOOORE EXPENSIVE!!!!

so please, if your car starts for now, take it to autozone or somewhere to get the battery and alternator tested. its free or really cheap, especially when compared to the price of an alternator or battery. you may go replace the alternator and find that you had a frayed ground wire -- easy fix coulda saved you $150 or 200. and a corroded battery terminal could cause plenty of intermittent electrical problems.

so just take it somewhere and get it tested real quick before you get the wallet out!
settled4automatic is offline  
Old 11-13-2006, 02:21 AM
  #5  
mattdel
6th Gear Member
 
mattdel's Avatar
 
Join Date: Nov 2006
Location: Spfld, MA
Posts: 9,240
Default RE: battery or alt

i agree with getting things tested, as i am a tech, but think about it. bad ground wires would produce constant discharge, not just when its idling. if the alt goes up in voltage as you increase RPM, its going bad.
mattdel is offline  
Old 11-13-2006, 02:47 AM
  #6  
Ninety5five0
5th Gear Member
 
Ninety5five0's Avatar
 
Join Date: Nov 2005
Location: Katy, Texas
Posts: 3,311
Default RE: battery or alt

I had to do a test today....turned out it was the guys alt....

But definatly get it tested first.
Ninety5five0 is offline  
Old 11-13-2006, 03:12 AM
  #7  
stang91
Thread Starter
 
stang91's Avatar
 
Join Date: Oct 2006
Posts: 22
Default RE: battery or alt

thank you guys
stang91 is offline  
Old 11-13-2006, 04:21 AM
  #8  
Twisted
5th Gear Member
 
Twisted's Avatar
 
Join Date: Feb 2006
Location:
Posts: 3,768
Default RE: battery or alt

ORIGINAL: mattdel

i agree with getting things tested, as i am a tech, but think about it. bad ground wires would produce constant discharge, not just when its idling. if the alt goes up in voltage as you increase RPM, its going bad.
Alternator voltage is supposed to go up when you increase the RPMs to above idle. I bet his alternator is fine, and his battery needs to be replaced. Either that or his terminals are all caked with deposits, and not allowing good conductivity through the cables.
Twisted is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BOB ROME
5.0L (1979-1995) Mustang
3
07-26-2023 01:54 PM
4cylinderplus2
V6 (1994-2004) Mustangs
10
10-09-2020 07:45 PM
logan409
4.6L (1996-2004 Modular) Mustang
10
09-26-2015 07:43 PM
wilsonro
4 Cylinder NA and Turbo
0
09-11-2015 07:13 AM
Art161
2005-2014 Mustangs
2
09-09-2015 10:33 AM



Quick Reply: battery or alt



All times are GMT -5. The time now is 09:41 AM.