Engine dies while driving.
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Thread: Engine dies while driving.

  1. #1
    NECO Member
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    Engine dies while driving.

    The car starts and drives for a while. good acceleration, no CEL lights or anything. Then it just dies and won't start.
    Brand new fuel pump. Pumps primes. No fuel pressure (I was pushing the Schrader valve in with a piece of wood; have to check for sure).
    Previous try: drove for 5 minutes. Died. was able to restart, but died 1/4 later; would not start.
    After 1/2 hour: started again (see beginning).
    All fuses are good.
    Can a fuel filter be so clogged (car was standing for 3 months, but fuel filter has less than 1000 miles on it) that it starves the engine?

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  3. #2
    NECO Member CodyTRX's Avatar
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    Re: Engine dies while driving.

    It seems like ND4SPD had a problem eerily similar to yours. Search ND4SPD, no start, and fuel pump and see what you come up with.

    Born 02/13/1999. Silver Frost Duratec MTX Sport -CougarDB-Cardomain-Facebook

  4. #3
    NECO Member megeh piggeh's Avatar
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    Re: Engine dies while driving.

    when it dies spray some starter fluid in the intake and see if it starts. then you know its a fuel problem. and yes a fuel filter can get that bad, but if its only been 1000 mi then you have a problem..
    cougardomain
    Quote Originally Posted by BigBalledOX View Post
    Oh lord, that poor car . . .
    Quote Originally Posted by k2ss View Post
    how does it respond?
    Quote Originally Posted by ND4SPD View Post
    ...like a giant metal turtle on wheels.

  5. #4
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    Re: Engine dies while driving.

    More trouble shooting: I hooked up a fuel pressure gauge with bypass to the schrader valve.
    - cold car: priming the pump moves pressure up, then drops (I assume somewhere is a fuel pressure sensor that provides feedback to the ECU to shut the pump off when pressure is reached, or the ECU just closes the pump relay for a given amount of time)
    - starting the engine (cold): starts right up, pressure goes to 50 psi.
    - I kept the engine running in idle (hood closed to capture the heat). Keeps running for 10 min or so, then just dies. zero fuel pressure.
    - turn igintion off, back on after a few seconds. Pressure builds and falls.
    - after a few minutes: priming (pressure) engine starts, but died quite quickly (2 minutes).
    - cranking (not starting) no pressure
    - priming: sometimes pressure, sometimes not

    I guy at Autozone said to check the vaccum (?) activated fuel pressure regulator. They could go bad (and maybe the rubber (?) membrane works when cold,but leaks when getting worm?

    Sounds as a possible reason. How best to check the fuel pressure regulator? Seems like the UIM has to come off to get to it. Anything that can be done without the UIM off?
    The regulator is $35 at Autzone.

  6. #5
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    Re: Engine dies while driving. And continues to die !!!

    Today I replaced the fuel pressure regulator (could figure out how to test the old one).

    Ignition "on" primes the system, fuel pressure goes up then goes back to zero as soon as priming time (1 second or so) is over and the pump stops.

    The manufacturer of the fuel pump confirms: the pump has a built in check valve.

    I am pretty sure the fuel system is supposed to remain pressurized. So that is a first indicator that something is odd.

    I started the car (starts right away). Runs smooth, idles smooth. Perfect, couldn't be better.

    I let it idle for 25 minutes, still running (garage, hood open, 50 degrees)

    I take it out of the garage and drive slowly 200 yards, engine dies.
    Won't start.

    I short the fuel pump (at the pump relay to keep it running all the time; fuel pressure is 55 psi with engine off. You can hear the fuel going past the fuel pressure regulator back into the return system.

    Won't start.

    Coolant temp gauge is in the middle (warm).

    NO CEL.

    I let the engine cool down (open hood, 20 degrees F outside).

    After 10 minutes, I restart the car, starts right away. Back up the 200 yards, drive up the driveway.

    Force the engine (in gear, foot on brakes), go back and forth a few times, rev to 4000, etc. For about 5 min. Eninge dies.

    I am more and more inclined to say it is NOT the fuel system (new fuel pump, new pressure regulator, fuel pressure is right there at 50 psi with engine running).

    Disturbing: fuel pressure goes down to zero as soon as pump stops.

    Through several such scenarios, it seems confirmed that engine or engine bay temperature is a contributing factor. It always starts when cold, always dies when warm (less a factor of time rather than temperature under the hood).

    Could it be ignition? We used the spark plugs from the 3.0l (40,000 miles), and (since we use the UIM and LIM from the 2.5) the wire, coil, etc. from the 2.5l. Could temperature (I am not talking hot, just warm when the engine dies).

    Suggestions, PLEASE, what to try next.

  7. #6
    Capital Curmudgeon Lifetime Platinum MemberModerator skater's Avatar
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    Re: Engine dies while driving. And continues to die !!!

    Quote Originally Posted by vtraudt View Post
    Disturbing: fuel pressure goes down to zero as soon as pump stops.
    Doesn't that make sense with a return system? The pressure pushes the fuel back into the gas tank. (At least, that's what I'd expect - I'm no expert on fuel systems.)
    1999 Cougar, Laser Red, 3.0L V6, MTX (a lot more fun)
    2014 Ram 2500 Big Horn 6.7L Diesel (Towzilla)
    2012 Honda Accord V6, ATX (daily)

  8. #7
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    Re: Engine dies while driving. And continues to die !!!

    Quote Originally Posted by skater View Post
    Doesn't that make sense with a return system? The pressure pushes the fuel back into the gas tank. (At least, that's what I'd expect - I'm no expert on fuel systems.)
    No expert here either: but I think the spring in the pressure regulator closes the return line with no vacuum, effectively 'trapping' the pressure between the closed return and the check valve in the pump. Experts will confirm that the system normally remains under pressure for hours (days?), and that's why we are instructed to always first 'depressurize' the system before working on it (press the Schrader valve in).

  9. #8
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    Re: Engine dies while driving - shut down by PCM?

    What sensors/conditions could instruct the PCM to shut the engine down?

    My thinking: when cold, the engine runs with 'basic' settings, not sure what sensor inputs are used for the 'basis' running (but those are the ones that a FINE, since the engine runs GREAT (cold).

    When warmed up, the PCM starts using (other/more) sensor inputs, and the ones it gets are missing/totally out of whack/etc.) and the PCM says: that's it, shut down. Those would be the ones I need to check (because they mess up the PCM?)

    Still phishing for ideas and input.

  10. #9
    NECO Member CodyTRX's Avatar
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    Re: Engine dies while driving.

    I know less about the fuel system than the average person on here but I know that the Duratec has been known to have ''warm or hot fuel starting problems.'' Seems to be what you're experiencing here.

    Search that around here, CEG and Google. I know you can come up with something.

    Born 02/13/1999. Silver Frost Duratec MTX Sport -CougarDB-Cardomain-Facebook

  11. #10
    Capital Curmudgeon Lifetime Platinum MemberModerator skater's Avatar
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    Re: Engine dies while driving. And continues to die !!!

    Quote Originally Posted by vtraudt View Post
    No expert here either: but I think the spring in the pressure regulator closes the return line with no vacuum, effectively 'trapping' the pressure between the closed return and the check valve in the pump. Experts will confirm that the system normally remains under pressure for hours (days?), and that's why we are instructed to always first 'depressurize' the system before working on it (press the Schrader valve in).
    That makes sense - otherwise the pump would run continuously when you turn the key on.
    1999 Cougar, Laser Red, 3.0L V6, MTX (a lot more fun)
    2014 Ram 2500 Big Horn 6.7L Diesel (Towzilla)
    2012 Honda Accord V6, ATX (daily)

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