Drivetrain Can I Use A9p Ecu With A T5 Manual Trans

Discussion in 'Fox 5.0 Mustang Tech' started by 07blowngt, Dec 7, 2013.


  1. 07blowngt

    07blowngt New Member

    Joined:
    Mar 5, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    2
    Location:
    Delaware
    Doing a t5 swap in a 93 notch. Did a 5.0 swap on this car and used a AOD. Now I am collecting parts to do a t5 swap and I thought I read a while back you can use a a9p ecu on a 5 speed. I can pick up a a9l local for $75.00.
    Would it make sense to just change out the a9p to the a9l, what all is needed to change both ways?
     
    #1
  2. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

    Joined:
    Feb 19, 2001
    Messages:
    21,649
    Likes Received:
    311
    Trophy Points:
    124
    Location:
    Massachusetts
    What wiring harness did you use in the car? All AOD harnessed for the trans harness and o2 harness?

    If the entire car car was swapped using AOD harness, use the AOD computer is the short simple answer.
     
    #2
  3. 07blowngt

    07blowngt New Member

    Joined:
    Mar 5, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    2
    Location:
    Delaware
    Is the main harness the same? I thought there was a plug in harness off the main to the trans? The entire harness is off a 93 which was diff from the older because of a relay for fuel pump. If I use the existing harness on the t5 with the ecu I wont have to change anything at all
     
    #3
  4. mikestang63

    mikestang63 Mustang Master

    Joined:
    Aug 28, 2012
    Messages:
    3,934
    Showcase:
    20
    Albums:
    1
    Likes Received:
    1,099
    Trophy Points:
    144
    Location:
    In the garage
    once you start swapping harnesses from different years and/or auto/stick, you are going to run into all kinds of issues with sensor/relay connection compatibility. I don't have it off the top of my head but there are differences in harnesses

    pre 87 are not MAF
    88-89 has MAF no airbag
    90 maf and aribag fuel relay under seat
    91-93 maf and airbag fuel relay not under seat

    The o2 sensor connections are different from stick to auto as they have different number of wires.

    You can use an A9P in a stick but not an A9L in an AOD.
     
    #4
  5. 07blowngt

    07blowngt New Member

    Joined:
    Mar 5, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    2
    Location:
    Delaware
    So it sounds like I will be OK all my harnesses are from 1993. My main harness is late 92/93
     
    #5
  6. Mustang5L5

    Mustang5L5 Car used in adult film "Highway Gangbang-InDaButt" SN Certified Technician Founding Member

    Joined:
    Feb 19, 2001
    Messages:
    21,649
    Likes Received:
    311
    Trophy Points:
    124
    Location:
    Massachusetts
    From an AOD car, or a 5spd
     
    #6
  7. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

    Joined:
    Mar 10, 2000
    Messages:
    21,743
    Likes Received:
    383
    Trophy Points:
    134
    Location:
    Dublin GA
    An A9P will work OK in a 5 speed car with a 5 speed O2 harness. I have done it and it worked OK.

    What I haven't done is to use an A9P with an Auto trans O2 harness in a 5 speed car. I can't say if that will work or not. I have my suspicions that there will be some no crank problems with the starter circuit.
     
    #7
  8. 07blowngt

    07blowngt New Member

    Joined:
    Mar 5, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    2
    Location:
    Delaware
    So I guess I will change out my o2 harness. what is the diff between the 2 ?
     
    #8
  9. mikestang63

    mikestang63 Mustang Master

    Joined:
    Aug 28, 2012
    Messages:
    3,934
    Showcase:
    20
    Albums:
    1
    Likes Received:
    1,099
    Trophy Points:
    144
    Location:
    In the garage

    Take a look at a diagram and you will see one grounds internally and one uses an external ground wire, Use the wrong harness and you can fry the computer.
     
    #9
  10. liljoe07

    liljoe07 Active Member

    Joined:
    Feb 18, 2009
    Messages:
    1,179
    Likes Received:
    14
    Trophy Points:
    39
    Location:
    Cartersville,Ga
    Go unplug your 02 harness, and start the car. Your suspicions will be gone. The 02 harness doesn't interupt the starter circuit.
     
    #10
  11. liljoe07

    liljoe07 Active Member

    Joined:
    Feb 18, 2009
    Messages:
    1,179
    Likes Received:
    14
    Trophy Points:
    39
    Location:
    Cartersville,Ga
    You dont need to source another 02 harness. You simply re-pin the harness you have now.

    Since you will be running a 5 speed transmission. Your loop on the back of the 02 harness needs to connect a blue/yellow wire to a purple/yellow wire. Look at how the harness is setup now. If its a mass air 02 harness, it will have a looped wire on the back of it. The loop is either purple/yellow or blue/yellow. And in factory AOD form, it should be connecting a white/pink(or purple), to a purple/yellow wire. Which is what you dont want when its converted to a 5 speed.
     
    #11

Share This Page