HELP - SW1 fuel pump not running

Discussion in 'Saturn S-series' started by Private, Oct 4, 2010.

  1. Private

    Private Guest

    I hope there is still someone here.

    I have a 98 SW1 that has not been on the road for a couple of years but has
    been regularly (@ 2-3 months) started and driven around a large yard to keep
    the gears and engine oiled. I always let the engine warm up fully and
    changed all fluids before putting in storage. Gas tank has been kept full
    with premium gas.

    The engine has always started easily and is in no way worn out (130k km.).

    When I recently tried to start the car,
    starter worked properly,
    would not fire,
    waited, then turned the key to run ( not starter) and listened for the fuel
    pump but could not hear the typical couple of seconds of operation.
    checked the fuse and found it burned out.
    changed battery, and fuse,
    no pump sound, burned new fuse,
    put primer gas in air intake,
    engine started right up and ran fine till gas gone,
    exchanged fuel pump relay and installed new fuse,
    still no sound from pump ( maybe a slight short sound ???)
    does not seem to be burning fuses immediately ???
    still will not start.

    What should I do next ? In the old days I would just give the pump a smack,
    but this pump is in the tank, and I do not want to pull it as it is a lot of

    I am looking for suggestions, as I want to eliminate the easy stuff first
    and hope that I am missing something obvious.

    Private, Oct 4, 2010
  2. If you've changed the fuse and the fuel pump relay and the fuel pump
    will still not run, you're pretty much down to the fuel pump itself. To
    remove it, you have to drop the fuel tank down from under the car and
    fuel pump is mounted in the top of the tank. Try and get as much of the
    gas out of the tank as you can before you lower the tank. The gas
    weighs 7 lbs per gallon so ten gallons of gas is 70 lbs and is much
    more difficult to handle. Also, there is a fire danger from gasoline
    fumes when you open the tank so try and remove the tank outdoors away
    from the many sources of ignition that exist indoors. The fuel might
    have failed due to the formation of a lot of gunk around the pump as the
    gas in the tank aged over the years or it might have failed from water
    in the bottom of the tank which froze and then the pump was activated or
    something like that. There's all kinds of stuff that happens with cars
    that are not driven for an extended length of time.
    David T. Johnson, Oct 4, 2010
  3. Private

    Oppie Guest

    There should be a connector near where the harness goes to the fuel tank.
    Disconnect it - you may be able to get to it without dropping the tank. Pull
    the fuel pump fuse and measure fuel pump current with an ammeter. With the
    pump disconnected, there should be no current flow. Looking for a short
    circuit in the harness before you drop the tank...

    One question though. Did you replace the fuel filter? If the filter gets
    plugged, the fuel pump pressure gets very high and can damage the pump or
    just blow fuses eventually. Any water in the fuel system tends to plug a
    filter almost immediately. Water molecules are much larger than gasoline
    molecules and plug the pores in the filter membrane. Pull the filter and let
    it drain into a glass jar. Look for water droplets. If you can blow through
    the filter (after it drains) - use a tube to blow through, the filter isn't

    While the filter is out, you can put an extension hose on the fuel line from
    the tank. Have someone turn the key to the on position. The fuel pump should
    run for about a second and stop if there are no trigger pulses from the
    engine (signaling engine rotation). If the pump is still good, you should
    get some fuel delivery.

    If you do wind up replacing the pump, be very careful. Even if you manage to
    drain or siphon all the fuel out of the tank, the fumes alone are explosive.
    Remove the negative battery terminal. Remove all connections to the tank and
    drop the tank. Helps to make a stack of 2x4's cris-crossed under the tank to
    help let it down slowly. Most of the tanks are plastic these days so
    sparking is not as big a problem.
    Back in the day when tanks were all metal, you'd wet down all the joints
    with something like WD-40 and and use brass tools (drift and mallet) to
    remove the locking ring that holds the pump into the tank. Brass is
    non-sparking and is less of a problem for ignition. Back in the day, there
    was always an access plate to get to the top of the fuel tank under the rear
    seat. Haven't seen one of those in some time.
    Don't forget to move your drained fuel far away from the work area and keep
    a BIG dry chemical or CO2 fire extinguisher close at hand!
    Oppie, Oct 5, 2010
  4. Private

    Doug Miller Guest

    That's good advice... but what follows is pure nonsense.

    Gasoline is mostly heptane, and a heptane molecule is FAR larger than a water
    molecule. Water consists of one oxygen atom and two hydrogens. A carbon atom
    is a bit smaller than an oxygen atom, but heptane has *seven* of them, plus
    sixteen hydrogens. A water molecule is positively tiny by comparison.
    He may have a plugged filter -- but it sure as hell isn't plugged with water.
    Doug Miller, Oct 7, 2010
  5. Private

    Oppie Guest

    You can't argue with experience though...
    I had a car that I neglected to change the fuel filter for some time. I had
    noted that the pump was running noisy and by the time I got a chance to look
    into the problem, the pump had failed.

    Replaced the pump and filter. tried to blow through the old filter and it
    was plugged up. In most fuel injection systems, the only pressure relief is
    the fuel pressure regulator on the injector rail. If the fuel lines get
    plugged, the pump will run at excessively high pressure, draw higher current
    and either blow the fuse or kill the pump itself.

    Had another time with a carbureted car that fuel filter screwed into carb
    body. Just filled the tank and while going through a bad section of town,
    the car died. Long story short, I removed the filter and the car started.
    Found about a pint of water in the gas tank that came with the fill-up.

    Prove it to yourself with an old filter. you can blow through it. Rinse
    water through it and you can't blow through it anymore.
    Oppie, Oct 7, 2010
  6. Private

    Doug Miller Guest

    Can't argue with ignorance either, obviously.
    Doug Miller, Oct 8, 2010
  7. Private

    Private Guest

    After ckecking the obvious and asking for advice here and elsewhere -

    I towed the car out of the high grass onto the smooth gravel where I could
    get under it for inspection and for access to the filter and fuel lines if
    As reported above, I had earlier changed the battery for a known functional
    (but older and used) one just in case the battery was part of the problem,
    but no change. I had also tried both used batteries with my charger
    connected and after charging for a while.

    I always like to enter the winter season with good batteries and at least
    one good spare ready for use if needed. IMHE batteries that seem to be
    functioning just fine in the summer will often fail at the first sign of
    cold and can cause other system damage when they fail. Before really
    getting serious and tearing anything apart, I thought I should install my
    newest battery (which I just purchased for another car).
    BINGO, turned the key, heard the pump then engine started right up and ran

    I might have dislodged or vibrated something when moving the vehicle or
    tapping the tank, but I doubt it as the ground was pretty smooth and I did
    not get too aggressive.

    I suspect that this is just another example of -
    1 - don't get in a hurry,
    2 - consult the manual, and knowledgable others,
    3 - think about the problem
    4 - do the easiest and most obvious stuff first.

    Thanks all here for their input, I will be buying a couple of new batteries
    as I prepare for winter. The older ones will go into machinery I use mainly
    in the summer months and do not need to depend on in winter.

    Good luck, YMMV
    Private, Oct 10, 2010
  8. Private

    Oppie Guest

    I'm not convinced that you solved the root problem. A vehicle that old
    invariably develops a bit of oxidation on chassis ground points and
    sometimes on connector pins. If any of the wire harnesses were abraded -
    particularly ones exposed to the elements, the wire core itself can corrode
    and give an intermittent circuit.

    True that some cars have very little allowance for low battery voltage while
    cranking. I believe that the absolute minimum voltage allowable to start the
    engine while cranking is 8V and probably closer to 9V. A new battery usually
    does not have as great a voltage drop while cranking.

    If it were my car, I would remove the fuel pump relay and bridge it -
    forcing the pump to run. Assuming that your injectors are not leaking, this
    should not let any fuel into the intake manifold.
    Now, go through the entire harness from the fuel pump relay back to the tank
    and wiggle wires, tap connectors... You should be able to hear the pump
    running and hear when/if it stops when you touch something.

    Don't recall on that car if there is a crank angle sensor (this car doesn't
    have a distributor??). Either way, something generates timing pulses when
    the engine is rotating to fire the spark plugs, inject fuel at the right
    time... If that pulse is intermittent, no starting. About that era, lots of
    cars had reluctor coils in the distributors to generate the ECU timing
    pulse. Most common problem an open coil. Remember, no pulse, no spark and no
    fuel pump.
    Like I wrote previously, at key on, the pump will run for about a second to
    prime the system. If there are no timing pulses, the pump shuts off again.

    Good luck
    Oppie (2001 lw300)
    Oppie, Oct 11, 2010
  9. Private

    Private Guest

    I agree with your comment regarding ground connections. My policy has been
    to always clean (and dielectric grease) ALL ground connections at the FIRST
    sign of electrical problems or aging and in fact had done this PM on all my
    Saturns this spring, (including the ground that requires the removal of the
    battery tray).

    In conversation with a Saturn tech last week I was told that in his opinion
    all Saturn wiring is undersized by a size or two and that he has had to
    replace several harnesses in his work. In the old days it was common
    practice to pierce the wiring with a probe when testing for power but this
    allows moisture to enter the wire and cause corrosion. I would think that
    this would be even more of a problem with undersized wire.

    I am hoping that I have solved my problem but will keep your suggestions in
    mind if I have continuing problems. Thanks for your input.
    Private, Oct 11, 2010
  10. Private

    Oppie Guest

    Remember that dielectric grease is non-conductive. It will do a good job of
    sealing any iffy connections against further corrosion. The best connection
    to ground is with a 'gas tight' connection that bites through any surface
    insulation. If there is a ground stud, for example. I remove the wires from
    the stud and put about 10 amps through it while measuring voltage drop with
    a meter. I have a fixture with an old headlamp which clips to the battery+
    and has a long lead for measuring chassis grounds. I've seen a few studs
    where the chassis connection is poor. Always good to use toothed lock
    washers (external tooth preferred). I learned the 'gas tight' bit when
    working on military equipment. The force of the connections keeps any oxygen
    from the connection and causing corrosion. I usually apply a bit of white
    grease from a spray can over the ground connections.

    Yeah, I hear you about the punctured connections. I always cringed when I
    saw techs doing that. Happens less now among pros who have access to good
    computer diagnostic gear. These days everything goes through a computer and
    can be diagnosed if you have big bucks to buy the equipment. Whenever I have
    to pierce a wire, I have a syringe of RTV caulk that fills in the hole.
    Oppie, Oct 11, 2010
  11. Private

    Oppie Guest

    .... but what follows is pure nonsense.
    (Hangs head in shame) You're right. Don't know what I was thinking.
    Was ruminating about this old discussion and realized it wasn't molecule
    size. Rather, when the paper filter membrane absorbs water, it swells and
    the pores close off making it impermeable. The pores do not appreciably
    change size in clean fuel.
    Oppie, May 18, 2011
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.