Volvo 740 GLE starts then stalls after 30 seconds

Discussion in 'Volvo 740' started by johnzab, Dec 13, 2006.

  1. johnzab

    johnzab Guest

    Help !! I have a 740 GLE 2.3. I have replaced the intank and undercar
    fuel pumps and filters. The car starts up normally then quits after 30
    seconds or so. It started happening as the weather started cooling
    down. Problem started at about 45 F. The car also has a new Air Mass
    Unit and the fuel injectors have been replaced.

    Any help welcomed !!
     
    johnzab, Dec 13, 2006
    #1
  2. johnzab

    Tony Guest

    Need more info

    Does it restart straight away, or will it not run atall then?
    Does it go for 30s each time.

    Have you tried holding the throttle open or reving it when you are
    expecting it to fail.

    Can you not drive the car and get it warmed up?

    As an initial guess the fuel pressure regulator could be faulty and may
    be allowing too much fuel to return to the tank.
     
    Tony, Dec 13, 2006
    #2
  3. A good cleanup of the throttle body should help. The 740s get a lot of
    vaporized glop from the crankcase that loves to collect in the throttle
    body. Especially ensure the idle passage at the bottom of the body gets
    cleaned out. At the same time, the idle air control valve under the throttle
    body should be cleaned to keep it free-moving.

    Mike
     
    Michael Pardee, Dec 13, 2006
    #3
  4. Have you tried Dry Gas? I would add two cans.
     
    Stephen Henning, Dec 14, 2006
    #4
  5. johnzab

    johnzab Guest

    Tony,

    It will restart within a few seconds and run for another 30 seconds
    give or take.

    Yes, tried holding it open and pumping the throttle.

    Wont run long enough to move it. Does run a bit longer when in gear
    though, maybe close to a minute before stalling.

    I have not changed the pressure regulator.

    Thanks

    John
     
    johnzab, Dec 14, 2006
    #5
  6. johnzab

    johnzab Guest

    Mike,

    I have cleaned the throttle body, but not the air bypass valve. I will
    give it a try.

    Thanks
    John
     
    johnzab, Dec 14, 2006
    #6
  7. johnzab

    Tony Guest

    Its not obvously the pressure reg, but its the only thing I could think
    of that might 'run out' a bit like a carb car running until the fuel in
    the carb ran out if there was no fuel supply. Possibly its suddenly
    releasing pressure.

    You have already eliminated fuel system blockages in the main areas,
    could there be something in a pipe?

    It must be something faily blatant that is causing total shut down, I
    guess the questions are:

    Is the Engine Mgt shutting it down due to an out of spec sensor (eg
    crank sensor)?

    Is a key running system diing, ie fuel or spark due to.. eg an
    electrical fault heating up for some reason?

    Restarting straight away would say to me its mechanical rather than
    electrical and so eliminate spark problems.

    Running longer when in gear is a clue, but I don't know why. I assume
    you mean automatic drive 'in gear'. This would mean there is some load
    on the engine, possibly drawing more fuel and keeping the pressure
    regulator away from its sudden release point for longer. However it
    seems a highly unlikely failure mechanism to be so time constant. Maybe
    pressure builds up because it is sticky and then suddenly releases
    totally because the spring is broken.

    A mechanic should be able to test the fuel pressure, but its probably
    cheaper to eliminate the regulator by replacement.

    Perhaps you could monitor the tank return feed, it could be dry then
    suddenly gush just before it stalls as it losses pressure. I don't know
    what would happen if the return feed was blocked, but if you could try
    that briefly it might run on.
     
    Tony, Dec 16, 2006
    #7
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