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  1. #1
    Seriously Northern Bmeagher's Avatar
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    What happens when the FPDM go bad?

    When they get bad, is there any fuel pressure? Or does it quit all together?
    Comp Cams 106100's, longtubes, FR500 intake + Roy's 2" spacer, 4.30's, Fidanza Aluminum Flywheel, Centre force Df, Ford GT Followers+Livernois springs
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  2. #2
    Red 99 Cobra
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    Fpdm

    Check your reset button first. Its located behind the trunk panel on the driver's side - rear. All it takes is a bump while you're in the trunk to make it trip off.
    Normally when the driver (FPDM) goes bad, there is no fuel pressure because the fuel pump is not working.
    Rio Red 99 Cobra: Mac LT's, Pro-Chamber, Flowmasters, 17X9 Chrome Cobra "R" wheels, 410's, Full-Length Sub-Frames, Steeda Tri-Ax Shifter, Diablosport Predator, JLT CAI, DTP Dyno Tune (318 RWHP / 313 RWTQ), H&R Race Springs (urethane isolators), Bilstein Shocks/Struts, IRS Bushings (front & rear), subframe bushings and Kenny Brown Torque Brace.

  3. #3
    SVT God
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    Mine did not have any fuel pressure when you mashed the gas pedal.. Unplug sensor and try it again it will have I think 30 psi.. Mine went bad last winter and the car would not run... I unplugged the sensor and the car would run fine,but the check engine light would come on..

  4. #4
    4cams aren't better then1
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    Tango, sounds like you are talking about the Fuel rail pressure sensor, not the FPDM.

    A bad FPDM will throw a code. In most cases the issues relate to thermal limiting from driving pumps that suck too much power.
    05 MB S500, 96 911 turbo

  5. #5
    Seriously Northern Bmeagher's Avatar
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    It's a driveability problem, it's fully tune. No problems till this weekend, driving in 4th and 5th gear the car lean's right pass 17.1 a/f ratio on my wideband. And you can feel it, almost starving for fuel. If the fuel pressure sensor was bad, there would be a code. If the inersha switch (don't mind the bad spelling) it would have no fuel pressure. If the the fpdm was bad, same thing. So this points me to a bad fuel pump, or a pump on it's way out. But the car only has 30,000 miles. Fuel pressure checked in at 28@idle, and 38 with the vacuum off.
    Any help guys?
    Thanks

  6. #6
    4cams aren't better then1
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    Your fuel pressure sounds pretty good.

    most bad frps don't throw a code.

    Does it start up ok? Ever shut off on you?

    whats your fuel pressure doing when it starts to go lean?

  7. #7
    Seriously Northern Bmeagher's Avatar
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    Starts up ok, never shuts off. Never test drove it with the gauge on. But when i pulled the vacuum line off the pressure switch, it spikes at 38. Then when i reinstalled the vacuum line it would drop below 20. I asked a ford tech, and he said if the FPDM is in the trunk, usually they don't have trouble. He said, by the sounds of things it's the pump getting weak.

  8. #8
    4cams aren't better then1
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    I agree that its not the fpdm.

    That said, I think the only way you can tell for sure is to datalog fuel pressure with a/f to see whats going on.

  9. #9
    Seriously Northern Bmeagher's Avatar
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    I'll grab my gauge from work tomorrow, and test it out tomorrow night.
    Thanks

  10. #10
    Seriously Northern Bmeagher's Avatar
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    Well.....fuel pressure at idle after took it for a drive with the gauge on was 24psi.
    With the vaccum off was 36. When it was leaning over to 16.8-17 crusing, it was maybe 22psi. Which in my eyes, points to the fuel pump.
    Anyone know where i can get a svt focus pump? Also, when you install the focus pumps, how do you re-install the crimp flex line in the tank unit?

    Thanks guys

  11. #11
    4cams aren't better then1
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    focus pump is not a good solution.

  12. #12
    Seriously Northern Bmeagher's Avatar
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    What do you recommend?

  13. #13
    4cams aren't better then1
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    I like the Ford GT pump or a stock replacement if you aren't making over say 330rwhp.

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