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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

low voltage problem. help!!

  • Thread starter Thread starter gwmcgowa
  • Start date Start date Feb 24, 2010
G

gwmcgowa

New Member
Feb 23, 2010
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Feb 24, 2010
#1
  • Feb 24, 2010
  • #1
I have an 89 mustang lx 5.0 and I am having low voltage problems. I have replaced the stock alternator 3 times and tried 3 different batteries and the voltage at idle rarely passes 11.8 give or take a tenth. This causes the car battery to lose all voltage and the car shuts off and needs to be jump started. once its jumped, it will run alright until i shut it off again or it dies, and then it will need another jump start. Any input?? I just ordered a 140 amp alternator to see if that helps and i will be buying a new bigger battery as well.

I can give more details about the accessories I am running if need be.

If i upgrade the alternator and battery and the low voltage still remains, what else might the problem be?
 
M

MustangBill87

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Jul 14, 2009
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Feb 24, 2010
#2
  • Feb 24, 2010
  • #2
You need to check out the 3-G alternator conversion thread at the top of the 5.0 Tech "Technical thread list" get a 130 amp alt. for 95 5.0 stang and follow what the thread says to do.
 
G

gwmcgowa

New Member
Feb 23, 2010
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0
Feb 24, 2010
#3
  • Feb 24, 2010
  • #3
I actually just bought a 140 amp 1 wire from summitracing, from my understanding the only difference between this and a 3g is that for this one to be activated the RPMs need to reach 1200. Is this the case? or should i revoke my order and get a 3g?
 
M

MustangBill87

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Jul 14, 2009
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Feb 24, 2010
#4
  • Feb 24, 2010
  • #4
The 3-g will activate at 750 or 800 rpm and be able to power everything on your car at that rpm, you would be able to sit at idle with 14.5v
 
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gwmcgowa

New Member
Feb 23, 2010
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Feb 24, 2010
#5
  • Feb 24, 2010
  • #5
as compared to what with the 1 wire?
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Feb 24, 2010
#6
  • Feb 24, 2010
  • #6
Did you have the system tested? Were the alts bench tested? That will be the only way to know what's going on.
 
G

gwmcgowa

New Member
Feb 23, 2010
25
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0
Feb 24, 2010
#7
  • Feb 24, 2010
  • #7
The first alternator was bad so i replaced it, the second one was good but the problem still remains so i just ordered a bigger one.
 
G

gwmcgowa

New Member
Feb 23, 2010
25
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0
Feb 24, 2010
#8
  • Feb 24, 2010
  • #8
ps. i have a working aod on my car right now id get rid of. i have another one i am repairing that has a shift kit and stall conv so i wont need this one anymore. its stock
 
G

gwmcgowa

New Member
Feb 23, 2010
25
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0
Feb 26, 2010
#9
  • Feb 26, 2010
  • #9
FYI i replaced the alternator today with a 1wire 140 amp and the problem was fixed, car runs like a dream again! thanks for your insight
 
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