Wiring Harness Connector Questions - Black & Grey 8 Pin

Discussion in 'Fox 5.0 Mustang Tech' started by rock4451, Jan 1, 2014.

  1. I'm using an 89 harness to put a 5.0 into my 86, almost done, except a couple hold-ups.
    There are 2 connectors on the driver's side, a grey 8 pin and black 8 pin (could be brown, it is faded) pictures are below. I am running NO A/C on this car, mechanical gauges that are all done and wired, but according to some diagrams these wires for the connectors are to do with my TFI and dizzy, so I want to make sure they are right in order for the car to run.


    This is the one (above) on my 89 engine harness but there is one on my 86 harness that goes through the driver's side firewall into the engine bay that is identical in shape and the wire colors are mostly the same, too. The one on my 86 is below:
    Any help where these go would be great. Is it possible that during the years, they changed the male/female connector side? If that's the case, I can easily repin an 8 pin connector so that they plug right up as they're supposed to connect. They're basically the same plug but one is on the harness to go into my car on the driver's side firewall and one is attached on the 89 main engine harness. They are both female connectors.

    Below is the grey connector, which is also on the 89 main engine harness:

    There are no male connectors for these that I see...they are just hanging there but I KNOW with this many wires, they have to go somewhere.

    This is the last step of my wiring then I can test start my car! Any help would be great.
    #1 rock4451, Jan 1, 2014
    Last edited: Jan 2, 2014
  2. Pictures no worky...
    The link goes to your private Gmail account, which can't be accessed without your password.
    Post them on www.photobucket.com or some other photo hosting service

    Select the IMG tag with Photobucket and it will format the text screen so that it works OK with Stangnet.
    use the following syntax :[​IMG]
    Stangnet will host photos related to your post, but there is a size limitation.
  3. It should work now, sorry for the hold up!
    I know the lights are kind of bright in the pictures, I took these last night and didn't think to mark down the exact wire colors that go into each connector. If that would help, I can do that as well.
  4. So here are the connectors I'm having trouble with, and I've discovered I'm most likely using a 90-91 harness. I have the diagram mostly figured out, but the Light Blue/Yellow wires are having me 2nd guess myself.
    On the 86 connector, light blue/yellow says it goes to PIN 30 of the EEC, where should I match this up with a plug on one of the black or grey connectors on the 90 connectors? I don't see anything on the 90 harness that goes to pin 30. I assumed since the 90 harness's Light blue/yellow needs to go to the neutral safety circuit, this wiring would work since connecting the light blue/yellow from the 90 harness to the same colored wire on the 86 harness would connect it to the neutral safety circuit.

    Thanks again for those diagrams, those were super helpful.
  5. Hope this helps...

    See http://slantnosefox.com/picturehosting/jeremy/86 electrical & vacuum troubleshooting manual.zip you can download the whole set of electrical troubleshooting and diagrams for an 86 Mustang courtesy of Jeremy, AKA V8only.
    It is a big 61 MB download that you get to unzip and save on your computer. It may take some time to download it, but the results are worth your time.

    @v8only Can you help?

    O2 Sensor harness interchange and modification

    Originally Posted by 302EFI

    Revised 16-Oct-2011 to add O2 sensor harness warnings
    The wires for the 02's and low oil did not change throughout the years, they are all in the same place.
    The main ones you need to worry about are (on the harness end (ECU) that plugs into the 02 plug) is:
    \- 1. Lightblue / yellow
    - 2. White / Purple
    - 3. Purple / Yellow
    The White/Purple & Purple/Yellow gets looped for a automatic ECU
    The Purple/Yellow & Lightblue/Yellow for a manual ECU

    See http://forums.corral.net/forums/gen...manual-auto-differences-year-differences.html for more O2 sensor wiring harness info

    Basic premise to use with transmission swaps:
    Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
    Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans will cause no crank problems.
    See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 for Joel5.0’s fix to the computer internal signal ground.

    90 model year harness only works with 90 model cars without inspection/rework.
    The 4 cylinder O2 harness uses 4 wire O2 sensors. It probably won’t work correctly without modifying it.
  6. Ive got a pretty stock 86 ssp in the driveway collecting cobwebs...ill take some pics of all the connectors and where they go after in a while
  7. These r the main connectors for my 86..lemme know if any of them look familiar

    Attached Files:

  8. Couple more

    Attached Files: