S40 hard starting, uneven running

Discussion in 'Volvo S40' started by blurp, Sep 18, 2009.

  1. blurp

    blurp Guest

    Hi all,

    I'm hoping to get some direction as to what and where to test with the
    purpose of getting to a diagnosis on a problem with my 2001 S40 1.9T
    (auto with about 240K).

    Since I've had this car it's been quite reliable and has had few
    problems (except the recently fixed turn-signal issue). About a month
    ago it began getting a little harder to start. The starter motor would
    turn but the engine wouldn't catch for a few seconds. Over the past
    several weeks this time before starting has been getting longer.

    A few observations:

    1. The hard starting happens always when the engine is cold and about
    50% of the time when it's hot.
    2. When it cranks for a long time (5 seconds) before catching there's
    a strong smell of gasoline
    3. The starter motor cranks hard and steady, there's no sign of weak
    4. It has not yet failed to start or stalled out while running.
    5. Once it starts it doesn't idle smoothly insofar as it seems to
    'miss' every now and again and give a little shudder. No noise, just a
    very short gap in the otherwise even idle.

    What I've done to make it worse :)
    A couple of weeks ago I had a driveway to work in so I picked up some
    spark plugs thinking they might be the problem. Unfortunately I
    couldn't find a gapping tool OR the appropriate gap specifications for
    this car so I just swapped them anyway because the old plugs were in
    pretty bad shape (the plastic around the annode was almost entirely
    worn away and blackened). Since that time the idle has worsened and
    there have been more misses at highway speed. I suppose that when I
    address this (does anyone have the right spark gap measurement for
    this car? I can't find it in VADIS) I'll need to use new plugs again.

    A few more observations:
    6. The tach shows idling RPMs a bit low, looks like approx. 600rpm.
    7. The 4 spark plugs are fed by two ordinary wires and two that have a
    sealed box just above the plug socket. In researching them on VADIS I
    found that the springs inside the sockets were supposed to protrude
    5mm when disconnected from the spark plug but these did not:they were
    compressed to even with or lower than the socket edge.

    So if that information makes the problem obvious to anyone then that's
    great but more likely you might have suggestions on what to test or
    inspect to work towards a conclusion.

    Whatever you've got I'll take with thanks!

    blurp, Sep 18, 2009
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  2. blurp

    Lloyd W. Guest

    My '01 S40 (150K miles) had a similar problem - turns out it was the fuel
    Lloyd W., Sep 18, 2009
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  3. blurp

    GlennK Guest

    From what you are describing it sounds like the fuel pressure regulator
    is on it's way out not very hard to change remove the fuel line going in
    to the regulator remove the torx screw from the side of the fuel rail
    very slowly work out the regulator install is opposite of removal
    Glenn K
    Volvo Certified Technician 2008
    ASE Certified Technician 2008
    GlennK, Sep 18, 2009
  4. My 2000 S40, which now has just over 200,000 miles on it, has similar
    problems. I have pretty much ignored the hard starting and it has not
    gotten any more serious in the two plus years that has been an issue. As
    far as the rough idle/missing, I've used a can of Seafoam about once a month
    and that seems to clear things up pretty well. Despite the troubles
    described, this car has been a trooper for me since I got it new in Nov. of
    1999. Maybe I'll give the fuel pressure regulator a shot and see if I can
    get a few more years out of her. The suspension and body are starting to
    show their age though.
    Steve and Amy Bernth, Sep 19, 2009
  5. blurp

    blurp Guest

    Thanks for the responses I've received, it's good to have something
    specific to start chasing down.

    So is there any way I could test the Fuel Pressure Regulator without
    removing it or am I just replacing it?
    blurp, Sep 21, 2009
  6. blurp

    blurp Guest


    I went to inspect the fuel pressure regulator and found that the short
    length of U-shaped hose that connected the regulator to the engine
    (the black part AFTER the short length of cream-coloured hose) had
    cracks in it. So if it's leaking at those cracks is it leaking fuel
    out or leaking air in? The hose seemed dry and dusty so I don't think
    anything has come out of those cracks.

    The dealer says they sell the double-ended S-shaped hose assembly for
    $14 so I think that's what I'll go pick up today after work. Any
    procedural suggestions re: swapping that out? Is there going to be
    residual pressure in the fuel system when I take the thing off? Can I
    alleviate that by opening the fuel tank? Will I need to bleed the fuel
    system afterwards for fear of air bubbles or will it correct itself?

    I don't have any experience working with the fuel system and want to
    be as safe as possible.

    blurp, Sep 21, 2009
  7. blurp

    blurp Guest

    ANOTHER UPDATE (bottom):

    I found this beautiful step-by-step for other users:


    and I believe the part I'm seeing the cracks in is a vacuum hose so
    I'm increasingly thinking no fuel is likely to come out as a result of
    this repair.

    Hopefully I can change this hose without having to completely remove
    the FPR.

    Any advice/suggestions still welcome!

    blurp, Sep 21, 2009
  8. blurp

    James Sweet Guest

    The hose is a vacuum line that allows the regulator to maintain a
    constant pressure across the injectors as the pressure in the manifold
    changes. No fuel will come out if it leaks, but the fuel pressure will
    not be correct under many circumstances, as well as it creates a vacuum
    leak into the intake manifold which will cause the engine to run poorly.
    James Sweet, Sep 22, 2009
  9. blurp

    blurp Guest

    That sounds promising, I picked up the replacement hose
    this evening and hope to swap it tomorrow. It'd be nice to solve this
    with a $14 part. So the stuff in my previous post about gapping the
    plugs... can I rely on them being correct right out of the box? What
    if i had got the plug with 4 grounds?

    blurp, Sep 22, 2009
  10. blurp

    James Sweet Guest

    Generally no, you can get pregapped plugs, but it's always a good idea
    to check them, a gapping tool is usually under a dollar.

    Those multi-electrode plugs are a gimmick, just get plain plugs of the
    correct heat range, I've had good luck with NGK. If you pay more than $3
    each, you got ripped off.
    James Sweet, Sep 22, 2009
  11. blurp

    blurp Guest

    That's what I was afraid of... I'm going to have to pull those plugs
    again once I geet a gapping tool. Just got the correct gap a few
    minutes ago: 0.70 to 0.80mm. I got the Bosch Platinum with one ground.

    blurp, Sep 22, 2009
  12. blurp

    blurp Guest

    Swapped out the little vacuum hose to the regulator and all appears to
    be well.

    Thanks a bunch!
    blurp, Sep 26, 2009
  13. blurp

    blurp Guest

    Ooops, spoke too soon! It was better for a day and now it's back to as
    it was. Perhaps I jarred the regulator when installing he vacuum hose
    and it worked for a day and hen went back to failing.

    sigh. next I guess I try a new regulator ($300).

    blurp, Sep 27, 2009
  14. blurp

    blurp Guest

    This seems to be a job that never ends! New Thread to follow.

    blurp, Feb 23, 2010
  15. blurp

    Uncle Albert Guest

    Anyone fitted them to a 2001 S80?
    Uncle Albert, Mar 15, 2010
  16. blurp

    James Sweet Guest

    What sort of LED lights? Interior lights? Marker lights? Brake lights?
    Headlights? Fog lights?
    James Sweet, Mar 16, 2010
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