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Thread: SEFI conversion to MAS

  1. #1
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    Default SEFI conversion to MAS

    I am looking for information on this conversion -- i have a 1987 cougar orignal 5.0 fuel injected , installed new "HO" (roller cam with bbk intake ,GT40 alum heads , 24lbs injectors 70mm throttle body 70 mm bbk air meter) with a9l procesor - i have some driveability issues that may or may not be related to the conversion , but i have been told that the injector harness MUST be changed by some car guys , others say that it wont matter -the ecu fires them the same as fireing order of ho cam ? any ideas on this ---its a T5 car also

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    Best to look at the pinout for both ECU's for injectors. If pinout is the same you should be ok since the ECU program takes care of injector fire order.

    Drivability issues? A9L, 70mm TB, 24lb Injectors , aftermarket MAF and what cam? I hope you are tuning. without a tune it will run ok but will likely have low speed cruise issues like​ bucking, surging and a high erratic idle.

    John

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    You DO NOT change the injector harness or the pinout for the firing order. The place where the pinout is different is the Tab/tad sensors (emissions) and the fact that there's no VSS wire (pin 6 I believe) on the stock 87 main harness. There's also no secondary fuel pump wire, however that does not affect driveability.

    All the info is here. http://www.coolcats.net/modifying/massair.html
    Last edited by V8Demon; 03-15-2017 at 07:24 AM. Reason: My phone's autocorrect is a bastard.
    -- 05 Mustang GT-Whipplecharged !! -- 87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's! http://www.fquick.com/V8Demon

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    Used the above link 10 years ago when I converted to MAF (with an A9P). Has always worked great.
    '88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, Edelbrock 70mm TB, 76mm C&L MAF, 30lb injectors, 2.5" exhaust, AOD with 2800 PI converter, 8.8 with 3.73 gears, 31 spline Traction-Lok, 31 spline Moser axles, 04 Cobra front arms, Maximum Motorsports extreme duty rear arms, subframes.
    '11 Focus, '12 Mustang 3.7, '17 Accord EX-L V6

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    thanks for the info , the car runs ok , but as mentioned by the first post , i do have some surging at cruse- also very flat (no throttle responce ) cold start after driving 3-5 mins clears after about a min (seems like hours)
    the reason i ask about the harness is that this has been about a 15 year project -collecting parts from here and there (except for main performance parts --ie new block heads, cam (motorsport e cam) mass air flow )
    the harneses throttlebody bbk ssi intake ect "lovingly used(HA HA )
    if it were just a mass conversion straight up i dont think i would have the concerns - orignal engine was 5.0 just not HO - also it now has a T5 --i expected some idle issues

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    this is the package i have put together

    stock HO short block (rebuilt)
    motorsport X307 gt-40 heads (alum)
    motorsport M-6250-F303 cam
    BBK SSI upper/ lower intake
    24lbs injectors
    BBK 70 mm mass air
    70 mm throttle body (lightning)
    T5 trans
    3:73 gears

  7. #7
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    Pressure test your intake and soap it up. The SSI intake is notorious for leaking. Your setup is mild and should run pretty good. Tuning the injectors would make for stock drivability and fix the open loop cold start overly rich condition. It clears up once you get into closed loop and I imagine you are likely hitting the limits the ECU can correct for.

    John

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    Is it throwing any codes? Check for those first. It may be a mechanical issue or electrical. Pull the codes first and see what you're dealing with. The parts you have are not that radical. The car should run ok without a tune since you're running a calibrated MAF with the injectors.

    My Thunderbird (modifications in signature) idling. No tune and driveability is fine.
    '88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, Edelbrock 70mm TB, 76mm C&L MAF, 30lb injectors, 2.5" exhaust, AOD with 2800 PI converter, 8.8 with 3.73 gears, 31 spline Traction-Lok, 31 spline Moser axles, 04 Cobra front arms, Maximum Motorsports extreme duty rear arms, subframes.
    '11 Focus, '12 Mustang 3.7, '17 Accord EX-L V6

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    leaking at the base or some other spot ? i use a spray gasket sealer on each side of the gaskets

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    Is the mass air meter calibrated for the 24's?


    The symptoms you describe sound a lot like an unmatched meter............
    '84 Mustang, work in (sloooooooow) progress...
    '87 Stang notch
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    and a couple of tractors. Ford, of course.
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