Electrical gauges spike and battery discharges

Discussion in 'Fox 5.0 Mustang Tech' started by 83StangSGT(P), Apr 22, 2013.

  1. 83StangSGT(P)

    83StangSGT(P) Member

    Joined:
    Oct 12, 2009
    Messages:
    47
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Upstate NY
    I have an 83 gt and i have been having this problem since 2007. i was in SC at mustang week myrtle beach and my car had no issues. i parked it at a hotel and came back a few hours later and was dead. jump started it and i only have hi beams all four head lights on i just unplugged inside two so i can drive at night. switch to low beam no lows at all. after that. My gauges all spike about a quarter of the way up and my car will start to bog and stereo goes static and will cut in and out. I turn everything off and drive through it and my gauges will return to normal eventually. Ive changed about ten voltage regulators, 3 dimmer switches, 3 multi function switch, 3 alternators, 3 new batteries and swapped out of my 5.0 explorer that i dont have issues with just to make sure. 2 starters. Im fed up with this issue swapping charging system parts with no fixes. I'm color blind so i don't mess with wiring my self. Some days it will be fine others gauges will spike and just about leave me stranded. car doesnt like to start so good warm even with a brand new starter. i have wrapped my headers and my starter to protect from heat. Ive always ran an 8352pn pro billet dizzy back then still do. added a 6al box in 2011. Car runs like a raped ape when my gauges are normal. Weather has no bearing on this issue, ive figured out after driving it so long .temp gauge always between the o and r in norm. when it spikes just about in the red. fuel goes up a quarter tank. amp gauge doesn't move stays right in the middle. oil pressure also goes up the same rate as the three gauges total. Im lost with this issue. any help is greatly appreciated. My brother is a Chrysler certified master tech that i get free labor out of. he cant plug it in so he wants nothing to do with it.
     
    #1
  2. jrichker

    jrichker StangNet's favorite TOOL
    SN Certified Technician Founding Member

    Joined:
    Mar 10, 2000
    Messages:
    21,981
    Likes Received:
    428
    Trophy Points:
    134
    Location:
    Dublin GA
    You have a bad or missing engine to body ground. One of the symptoms is that the temp gauge rises as load such as lights or A/C- Heater blower is added.

    2.) The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.

    Any car that has a 3G or high output current alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects. The 3G has a 130 amp capacity, so you wire the power side with 4 gauge wire. It stands to reason that the ground side handles just as much current, so it needs to be 4 gauge too.

    The picture shows the common ground point for the battery , computer, & extra 3G alternator ground wire as described above in paragraph 2. A screwdriver points to the bolt that is the common ground point.

    The battery common ground is a 10 gauge pigtail with the computer ground attached to it.
    Picture courtesy timewarped1972
    [​IMG]
     
    #2
  3. 83StangSGT(P)

    83StangSGT(P) Member

    Joined:
    Oct 12, 2009
    Messages:
    47
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Upstate NY
    my battery ground is bolted to my block where the smog pump used to be roughly. My intake manifold ground i have going to the back of my fire wall. I have cleaned up the block and tightened up the grounds. This is a fresh set up. I put GT 40 3 bar heads on after dropping an intake valve last summer on E7 heads. Should i move my grounds. They are where they where when i bought it. Kid had a body kit and light bars under it. I have an 1986 saleen body kit waiting for it.
     

    Attached Files:

    #3
  4. 83StangSGT(P)

    83StangSGT(P) Member

    Joined:
    Oct 12, 2009
    Messages:
    47
    Likes Received:
    0
    Trophy Points:
    6
    Location:
    Upstate NY
    This car has begun to be an electrical night mare. My heater and defrost doesnt work on any speed. i slide it down to AC and the blower works good low and high. rear window defrost works good. I bought the car in 05 while i was in Iraq online having my dad looking at them. Motor is bored 60 over other than that it was bone stock when i got it.
     
    #4

Share This Page