your thoughts please

Discussion in '1994 - 1995 Specific Tech' started by BlackVert, Oct 26, 2004.


  1. BlackVert

    BlackVert Mustang Master

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    i recently installed a used stock fuel pressure regulator. i have the stock maf back in. and i have stock injectors.

    i set my high and low slopes back to stock (28.8/19.64). the kamrfs were around 1.15. i have lowered them both gradually. the high slope is now 17, low is 26. it is still lean, but not as lean.

    i am thinking it must be one of:

    (1) fpr is bad
    (2) fpr was dirty or rusty, injectors and/or fuel filter are now clogged
    (3) vacuum tube from intake to fpr is not very tight, not enough vacuum

    any other thoughts?
  2. BlackVert

    BlackVert Mustang Master

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  3. mytight95

    mytight95 Active Member

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    the reg is good........i assume you changed the values with the tweecer or something.........

    :shrug:.........

    only thing i can think of is if the car has mods.......you may need more pressure....PUMP.........or that the filter is clogged.......pump could be going bad....................hey man e-mail me what it is doing....[email protected].........are you checking the pressure with the vacuum off..............


    jason
  4. BlackVert

    BlackVert Mustang Master

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    ever run out of gas? it acts like it is on the verge of running out of gas.
    it was much worse on the way home.

    - i believe that the fpr is not bad
    - yes i changed the values with my tweecer.
    - my mods are not nearly extensive enough that there is no possible way i am maxxing out the injectors. the highest duty cycle i have seen is like 15%.
    - could be the pump - good point
    - i need to dig up my fuel pressure gauge and hook it up.
  5. mytight95

    mytight95 Active Member

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    yeah i would do that.............with the gauge............i would guess that the pump is going bad or the filter is clogged if you are only seeing 15% duty cycle...................


    you need to check the pressure.......check the filter etc. i think.................try and run it without vacuum on the reg.........block off the vacuum line from the intake.......drive it.........see how it does..............





    jason
  6. BlackVert

    BlackVert Mustang Master

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    stupid question time: will taking the vac line off increase the pressure or decrease it?
  7. BlackVert

    BlackVert Mustang Master

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    ok, i got the answer to this one: the pressure will go up.

    another question: after replacing the fpr, do you need to do anything to get the air out of the fuel lines?
  8. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    prime the pump. :D

    the system flows enough pressure to purge the system of air (unlike old low pressure mech pumps).

    good luck.

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