Injector harness ground wire

Discussion in 'General Tech' started by dsrtjeeper, Jul 30, 2015.

  1. dsrtjeeper

    dsrtjeeper New Member

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    Do the '95 GT's have one. I can't seem to find it. Any pictures or diagrams are greatly appreciated.
    Thanks!
     
  2. ttocs

    ttocs Legend

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    Looks like it is just a common ground system meaning that all 8 share one ground wire.
    [​IMG]
    Taken from the 94-95 orange mustang bible, electrical 24:4 :)
     
  3. dsrtjeeper

    dsrtjeeper New Member

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    So is this a floating ground that does not ground to chassis? I'm a little rusty on my electrical.
     
  4. ttocs

    ttocs Legend

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    There are two types of grounding systems. Common ground is were they all come to one wire that that goes to ground and floating where each injector would have its own wire that went to ground. "Floating" doesn't mean that it isn't grounded just that each one would have its own. As I said this is a common ground system. What are you wanting to know or needing to do?
     
  5. dsrtjeeper

    dsrtjeeper New Member

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    Basically; I cannot find that common ground wire. Supposedly it is suppose to attach to the rear of one of the heads.
     
  6. ttocs

    ttocs Legend

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    check the wire colors on the injectors and see what color is common and/or just trace them back. I believe the "R" that is next to each ground wire in the pic above refers to the color of red that ford liked to use for grounds back then.
     
  7. dsrtjeeper

    dsrtjeeper New Member

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    Red is the common color so supposedly the ground. In the pic you posted; the red goes to "Splice S127 on page 24-1"

    Would you mind checking that splice on that page or posting a pic? Thanks! I appreciate the help. I'm just not seeing any body grounds from the injection harness like I expected.
     
  8. ttocs

    ttocs Legend

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    well good thing we looked that up as it isn't a common ground but a negative trigger with a common hot.
    [​IMG]
     
  9. dsrtjeeper

    dsrtjeeper New Member

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    On that diagram it says to check "Grounds" on page 10-3. What a wild goose chase. Lol.
     
  10. ttocs

    ttocs Legend

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    that is the grounds for the pcm
     
  11. dsrtjeeper

    dsrtjeeper New Member

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    Ok. Thanks. I still can't figure out if the injector harness should have a body ground or if it's possibly grounded through the pcm. Am I missing something?
     
  12. ttocs

    ttocs Legend

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    First off I am just looking/reading the schematics and if someone else knows more or that I am wrong please correct me.

    From what I can tell it isn't a common ground like I said at first its exactly the opposite. What that means is that rather then the one common wire between all the injectors going to ground it goes to an +12v ignition wire, and then the ground signal from the computer is what activates the injector.

    Are you making your own harness?
     
  13. dsrtjeeper

    dsrtjeeper New Member

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    I'm using the factory harness but re-checking everything after installing the new engine. I've read where folks have had runability issues when the injector harness ground is not hooked up. This may be a Fox thing but I thought I'd check. I'm doing a few initial things before taking the car in for a tune.
     
  14. ttocs

    ttocs Legend

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    having just taken that harness off and then moved it in my attempt to tuck/hide all the wiring in the engine bay I can tell you that it is not grounded anywhere.
     
  15. dsrtjeeper

    dsrtjeeper New Member

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    Exactly what I needed to know. Thanks!
     
  16. kb1982

    kb1982 Active Member

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    One wire is a ecm ground and the other is a power wire. The ecm switches the ground to fire the injector, so the injectors use the ecm grounds.
     
  17. dsrtjeeper

    dsrtjeeper New Member

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    That's what I suspected. Thank you.