Could I Have Wrong Maf?

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by foxbody1989, Oct 13, 2013.


  1. foxbody1989

    foxbody1989 Member

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    So I have blue top injectors from what I get they're 24lb injectors. Looking on my maf I see the numbers f1zf-12b579-aa and under that is afh55-03b is this for 19lb injectors?
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  2. TOOLOW91

    TOOLOW91 Mustang Master

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    EEC determines injector cal. Does the car have an x3z computer? That would be from a 93 cobra and be correct for the injectors. Otherwise the way every uses included myself is a calibrated Maf that fools the computer to run the bigger injectors.
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  3. Mustang5L5

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

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    That particular MAF is a 55mm stock 91-93 mustang mAF.

    It was used with 19# injectors and factory EEC. Do you have a custom tune? Different computer? If not, then this is not the correct mAF for your application.
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  4. mikestang63

    mikestang63 Mustang Master

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    mismatched MAF and injectors. See if you have a chip on the EEC. If you have and A9l or A9P then it is calibrated for 19;bers not the 24
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  5. foxbody1989

    foxbody1989 Member

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    I will look. This car is a 92 ssp did they use different computers?
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  6. foxbody1989

    foxbody1989 Member

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    Computer said A9L. Anyway to tell if it has been custom tuned or chipped?
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  7. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    The OEM Ford MAFs are not calibrated to injector size. The injector sizing is done in the computer’s internal programming. Aftermarket MAF’s “lie” to the computer in an attempt to fool the computer into changing the injector pulse on timing to match the increased airflow.

    The A9L computer was standard equipment on 89-92 5.0 Mustangs with a 5 speed transmission. The only practical way to change the tune was to add a piggy back chip carrier that plugged into the circuit board using an externally mounted adapter. It is very obvious, since it sticks out of the computer housing on the end of the computer opposite the computer main wiring harness connector.

    The odd duck is the 93 Cobra computer, labeled X3Z which is internally calibrated for 24 lb injectors. Use the MAF & MAF sensor from the X3Z computer to avoid problems with the X3Z computer's internal calibration.
    Last edited: Oct 13, 2013
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