What determines the injector Firing order the ECU or Distributor

Discussion in 'Fox 5.0 Mustang Tech' started by 90lxcoupe, Aug 16, 2007.


  1. 90lxcoupe

    90lxcoupe Mustang Master

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    does the ECU know what cylinders are being fired from the distributor or is the firing order just set inside of the computer and it fires the injectors on the HO firing order?

    i have a NON HO cam in my motor and still have the factory computer

    i have heard that the injectors are firing on the same order as the distributor but have also been told that i need to re-pin my injector harness so that the injectors fire on the non HO firing order
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  2. vristang

    vristang Advanced Member

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    The ecu controls when the injectors fire, and this timing/order must match with the distributor set timing/order.

    If you try to 'repin' the injector harness you will end up moving one injector plug from the right side, to the left side, and vice versa.
    This will confuse the crap out of the ecu when it starts to adjust the injector pulsewidths based on feedback from the O2's.
    Remember that you have an O2 for each back of injectors, and that pulsewidths are modified by bank (groups of 4).

    Here is a link that describes what is going on...
    http://www.fordfuelinjection.com/?p=92


    I would ditch the non-HO cam, which will fix the problems.

    I don't feel like I am any good at explaining this, so let me know if you have questions...

    jason
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  3. 90lxcoupe

    90lxcoupe Mustang Master

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    that makes perfect sense, it just sucks that i've gotta pull the cam. what really ****es me off is that the guy i bought the motor from should have told me that the firing order was non HO BEFORE i put the motor in the car so i could have swapped it out then and it would have been no big deal :bang:
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  4. 90bluegt

    90bluegt Founding Member

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    If you get a tweecer you can change that in the ECU. Then you won't need to change the cam..

    Just a thought
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  5. 2002BLGT

    2002BLGT Well-Known Member

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    put an aftermarket cam in it ......the NON HO cam sucks ........it has something like a .420 lift , stock HO cam is .445 lift .......Bcam has always been a favored NA cam .480 lift .........Ecam is .498 .........
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