Hesitation while accelerating Saturn SL1

Discussion in 'Saturn S-series' started by Roger Ehrlich - Alumni-2004, Sep 24, 2004.

  1. I have a 1995 Saturn SL1, SOHC, manual transaxle, with
    145,000 Km (much on the hwy). I do change the engine oil frequently
    5000Km, check fluids often, etc. In the past two
    weeks, when accelerating, my car hesitates, it feels jumpy, or bucking/jerking.

    To resolve a recent stalling problem at deceleration and low rpm <2000rpm,
    I did the following:

    - changed fuel filter
    - cleaned carbon out of throttle body with carb cleaner (was
    O2 sensor safe), and there was alot of carbon...
    - replaced vacuum hose between throttle body and crank case, old one was
    weak & almost ready to collapse. (fuel/PCV line hose 11/32" ID, 50 PSI)
    -used STP concentrated fuel injector cleaner in gas tank.
    -spark plugs were gapped & changed last summer.
    -replace air filter

    I don't think it is a slipping clutch, because the clutch feels fine and
    grabs when I ease up on the clutch pedal when starting in 1st gear.
    Although I feel this bucking in gears 1, 2, 3, not so much in
    4/5....typically at lower rpm < 2500 rpm 1500 - 2200 rpm.

    It could be the ...
    -EGR valve
    -ignition wires
    -cap and rotor
    -MAF/MAP sensor (where are these located?)

    any suggestions?

    Thanks, Roger
    Roger Ehrlich - Alumni-2004, Sep 24, 2004
  2. Roger Ehrlich - Alumni-2004

    Blah Blah Guest

    Very good post. You covered a lot to eliminate a bunch of questions we
    here might of had to go through. I kinda suspect the EGR. It may not be
    closing off, at least not very well do to carbon. Btw Saturns never used
    cap and rotors.
    Blah Blah, Sep 24, 2004
  3. Good. you might want to just remove and clean again to get EVERYTHING.
    It's 2 10mm bolts and unplugging the cables. Really easy, at least on
    the dual hamster models.
    Maybe it did something. I don't trust those things though.
    Good too.

    Change those first. I bet the problem goes away. Mine was like this
    too, i changed the wires - ran a LOT better. It just feels like it's
    missing or hesitating every now and then, randomly? or, at low RPM, as
    the RPM increases, it suddenly 'kicks in'?
    None - it's a DIS system. A coil per plug.
    No MAF. MAP is on the intake manifold. I'm not sure about the single
    hamster motors, but the two hamster ones have it to the left end of the
    Replace the plug wires. Do it first. I bet it fixes it.
    Philip Nasadowski, Sep 25, 2004
  4. Thanks Philip & everyone

    Ok here's some more observations....

    Yesterday I did remove the EGR valve and there was much carbon in the
    valve and pipe. I used Carburator cleaner (sensor safe) to try & clean it.
    The valve seems to move/close more freely thereafter. I also
    replaced the PCV valve (FRAM PV295).

    However as I drove
    to work this morning and the car still felt like it was stumbling when
    accelerating. When gearing up from 1st to 2 & 3 my car hesitates, it feels
    jumpy, or stumbles with a lurching/bucking. My sense is that it
    seems like the clutch plate is slipping. However this symptom does not occur
    consistently. Sometimes it drives/feels very well. But when it happens it
    always does under lower rpm (1600-2500), typically as I am gearing up and
    accelerating with the gas pedal. I do not notice this under high rpm >3000
    rpm or when in gear 4 or 5 (maybe because of momentum). As I stated
    before, I tested the clutch, easing up on the pedal into 1st gear from a
    stationary position either on level ground or uphill, and the clutch does
    grab. Then if I press the gas pedal once in gear sometimes the jerking
    occurs. I cannot say that it appears to be a problem with the fuel pump.
    It primes fine when I turn the key to ACC, and the engine does not seem to
    sputter (like it's running out of gas). I'd suspect the clutch slipping if
    it was consistent. As Philip suggested I'll change the ignition wires to
    see if that does the trick (however when I changed the spark plugs last
    summer I did also measure the Resistance on the wires and they were
    fine). I would rather not spend money on changing the clutch plate or
    fuel pump if it is not necessary as these are very expensive.

    Thanks, Roger

    Very good post. You covered a lot to eliminate a bunch of questions we
    here might of had to go through. I kinda suspect the EGR. It may not be
    closing off, at least not very well do to carbon. Btw Saturns never used
    cap and rotors.
    Roger Ehrlich - Alumni-2004, Sep 27, 2004
  5. Roger Ehrlich - Alumni-2004

    pekerhed Guest

    I experienced a hesitation while accelerating with my 1999 Saturn
    SL1...then I started to notice a slight unusual sound. It ended up being
    the TIMING CHAIN. I got it replaced and that problem is over. Dunno if
    it's what you're problem is, but if it were, I would get it checked out.
    As you know, when that chain goes, so does your car.
    pekerhed, Sep 27, 2004
  6. Resistance measurements aren't really that useful, and if the wires are
    greater than 2 or 3 years old, they're suspect.

    At the really high volages that ignition systems work at, you can get
    interesting things even if the resistance checks OK, because the wire
    insulation could break down at high voltage, etc. I've seen it with TV
    sets a few times...
    Philip Nasadowski, Sep 28, 2004
  7. This matches the description as if you're driving on three cylinders,
    intermittently, as most suspected. There's no safe way to check for
    spark on the plugs or plug wires on DIS for DYIs, but perhaps one.
    Hookup an induction timing light. At low rpm you can observe carefully
    the consistent or inconsistent sparks. After finding the inconsistent
    cylinder, swap the plugs and try again to rule out a bad plug. DO NOT
    LEAN on the car's earth. At the really high voltages that ignition
    systems work at, and for unknown reasons, you can get an interesting
    shock that you'll remember a lifetime. I had my share.
    Ricky Spartacus, Sep 28, 2004
  8. Roger Ehrlich - Alumni-2004

    ~^Johnny^~ Guest

    A severe, but positive test for clutch slippage:
    Put it in 3rd gear, aply the parking brake, and try to "take off".
    Let the clutch out while revving the engine. The engine should die, even
    before the clutch pedal is all the way up.

    An even more brutal (but still more positive test) is to rev the engine to
    above 3000 RPM, in third gear with the clutch pedal down, parking brake
    applied. Without modulating the throttle, slowly let out the clutch. It
    should slow and stall the engine, evenly and eventually. Any upward blips in
    the engine speed could mean a worn throwout bearing, or weak dampener springs
    in the clutch disk. More severe slippage will, of course, be more obvious.
    Sounds more like weak spark on one or more cyls.
    One or more coils are weak, or you have bad spark plug cables.

    Take the car into a dark (I mean pitch-black) garage, run the engine at fast
    idle, around 1800 RPM, and raise the hood. Look for any visible sparking,
    corona discharge...

    Ignition coils can also cause this symptom when they go bad.
    ~^Johnny^~, Sep 29, 2004
  9. Thanks everyone. But about the spark plug cables.....

    I have noticed that the wire on cylinder 4 has a defective connector to
    the plug itself, sometimes it does pop off....I have used pliers to try
    and close the mating connector so that it is tighter. But I still suspect
    it...so I'll get new cables (Niehoff brand - a-ok? good brand? I don't
    need high performance cables, this car is a 1.9 L SOHC afterall ;) ...)

    A ? though, Would a misfiring plug feel different to the driver though? I
    feel the car lurching as if it lost power momentarily... and this happens
    only as I am gearing up, on level ground and up/downhill (any load to the
    wheels). I notice it more when gearing up from 1 to 2 to 3. Sometimes the
    car drives well though. I would think if a plug was misfiring the
    vibration would be more from the engine itself. Considering the trouble I
    had previously with lower rpm stalls, maybe I did not fully clean all the
    carbon from the EGR valve (carb clnr). I did the best I could with the EGR
    though. Maybe I should replace it also?????

    Roger Ehrlich
    Computer Science
    Ryerson University, Toronto, Canada
    "It is important that students bring a certain ragamuffin, barefoot,
    irreverence to their studies; they are not here to worship what is known,
    but to question it."
    Jacob Bronowski, The Ascent of Man

    "A common mistake that people make when trying to design something
    completely foolproof is to underestimate the ingenuity of complete fools."
    Douglas Adams
    Roger Ehrlich - Alumni-2004, Oct 4, 2004
  10. Roger Ehrlich - Alumni-2004

    Dave D. Guest

    I have a 1997 Saturn SL1. Two weeks after buying it used in 2000 I had
    a terrible missfire. Got home, found a bad spark plug wire, change
    them out and everything was okay for 3 years. Then about a year ago I
    had the miss-fire with moderate throttle. I changed the plug and wires
    and all was okay again until about 6 months ago. The car is fine when
    cold for about 5 minutes and then starts to buck, if I go lightly on
    the throttle it smooths out again. Since I don't drive it too far I
    have been living with it for several months. You know accelerate
    briskly and then back way off on the gas and it is okay. I have
    changed the plug wires and plugs (NKG) and still no good. Cleaned the
    EGR, throttle body with no luck. Upgraded from new stock wires to
    Accell 8MM and bosch platimum plugs. Still no good. I have a code
    reader and intermittently it pulls the code (forget the number, think
    for crank sensor) for the sensor my SL1 does not have. I tried
    reducing the spark plug gap from 40 to 32, still no good. I have a
    timing light and one interesting thing is that I get a good signal at
    idle but the timing light goes intermitent and even stops flashing for
    lenghty periods at higher rpms. (Checked my other vehicle and the
    strobe flashes at all engine speeds. Next I put a plug wire on a plug
    resting on the engine block and the spark is indeed there at all
    speeds. Guess just too week for the stobe pick-up. Last thing I tried
    yesterday evening was to open the spark gap to 45 thou. This morning
    was the first time my car has not jerked and hesitated on the way to
    work in months. It did do some minor bucking on the way home but the
    wife says it was okay for her tonight. Crossing my fingers on this one
    as I need to get GOVN't emmissions test soon.
    Dave D., Oct 21, 2004
  11. Roger Ehrlich - Alumni-2004

    Blah blah Guest

    They have crank sensors just not a cam sensors. I had a similar
    situation with a 3.8 and I reached down and could move the sensor
    around, it had worked loose and was rubbing on
    the...whatchamacallit...steel ring with what is often described as
    shutters. Anyhow I would suspect that unless it said "cam". In that case
    it would probably be the ignition module or something that has to do
    with "compression sense". Btw dont play with your plug gaps especially
    if they're platinum and be sure to check the resistance of your spark
    plug wires.
    Blah blah, Oct 21, 2004
  12. Check the routing. OBDII saturns are picky about plug wire routing
    because they need it to be the right way to sense something weird.

    After that, suspect the crank sensor, and if that's not it, ignition
    Philip Nasadowski, Oct 21, 2004
  13. Roger Ehrlich - Alumni-2004

    MyAutoWorks Guest

    I've had the exact same problem with my 96 SL1 for the last 4 years.
    (Since I bought it, used)

    After replacing plugs, plug wires, O2 sensors etc to try and fix the
    problem, I stumbled across this.


    I did as they recommended (Buy new plugs and gap them at 0.04 instead of
    0.06 and VOILA! The problem is long gone.

    The silliest thing imaginable, but it works.
    MyAutoWorks, Oct 22, 2004
  14. Roger Ehrlich - Alumni-2004

    Blah blah Guest

    First I've ever seen this. The TSB 96-T-25 does show up on Alldata.
    Thanks for the info.
    Blah blah, Oct 23, 2004
  15. Roger Ehrlich - Alumni-2004

    BANDIT2941 Guest

    Check the routing. OBDII saturns are picky about plug wire routing
    The error he is getting that he says the car doesn't have is likely a cam
    sensor error, which relies on the routing of the plug wires. The car doesn't in
    fact have a cam sensor per se, but with wires 1 and 4 routed next to each other
    near the coil it senses which cylinder is on the compression stroke; that
    acting as a cam sensor.
    BANDIT2941, Oct 25, 2004
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