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  •  » Please help diagnosing engine Idle issue

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    6/18/2020 8:46 AM  #1

    TremendousWand
    I FYI 24-7

    Offline

    Registered: 5/16/2013
    Posts: 657

    Please help diagnosing engine Idle issue

    1966 Mustang Coupe, 1988 5.0 Swap, GT40 Heads, GT40 Intake, EFI, MAF, T5z, MSD 6A

    Car is running again after replacing the cylinder heads and intake.  Had a blown head gaskets and busted valve in the old heads so I did some part swaps and repairs.  Read a lot on 86-95 5.0 engine idle issues.  Just going through the process.  I have the base timing set to 12 Degrees BTDC.


    -Still got light smoke coming from the exhaust.  No smell, no fluids coming from pipes and it's even now as opposed to before.
    -Can't get the engine to run at idle like it should.  Tried setting the initial idle to deal with some surging but didn't get much improvement.  Not sure I did it right. I couldn't get the car to start with the idle motor disconnected so I'm not sure how to set the base timing w/o doing that.
    -Got a very lite 'pat pat pat pat' sound coming from the exhaust at idle too.

    Give it a listen:
    https://streamable.com/8kwwt4

    Any help would be appreciated.

     

    6/18/2020 9:44 PM  #2

    6sally6
    Hyper FYIFORD ADDICT

    Offline

    From: Surfside Beach,SC
    Registered: 4/02/2013
    Posts: 6,855

    Re: Please help diagnosing engine Idle issue

    FI........can't help ya.   All that 'stuff' is black magic anyhow!!!


    J/K.......
    .the smoke COULD just be left over junk in the muffler/exhaust system.
    You DID spray around  (ALL AROUND) the intake/heads area checking for vacuum leaks..........right?!
    That's half the battle.
    6s6

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    6/19/2020 6:41 AM  #3

    TKOPerformance
    Hyper FYIFORD ADDICT

    Offline

    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,506

    Re: Please help diagnosing engine Idle issue

    You don't disconnect the IAC to set base timing.  You unplug the inline spout connector.  This is either a small gray plug or a yellow wire with a male/female spade connector in it located near where the harness plugs into the TFI module.  The engine must be at operating temperature when you do this.

    Do that first.

    Then check to see if you have any codes in the ECU.

     

    6/19/2020 7:39 AM  #4

    TremendousWand
    I FYI 24-7

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    Registered: 5/16/2013
    Posts: 657

    Re: Please help diagnosing engine Idle issue

    TKOPerformance wrote:

    You don't disconnect the IAC to set base timing.  You unplug the inline spout connector.  This is either a small gray plug or a yellow wire with a male/female spade connector in it located near where the harness plugs into the TFI module.  The engine must be at operating temperature when you do this.

    Do that first.

    Then check to see if you have any codes in the ECU.

    Ok, so I learned something new.... I have a painless wiring harness.  The spout connector is located next to the ECU and not by the distributor.
    This explains why I haven't been able to set the timing correctly.  Will give it a shot today.

       •Thread Starter
     

     

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