UK Sonata V6 / 2000 engine suddenly feel underpowerwed and juddering from standing start

Discussion in 'Hyundai Sonata' started by Peter, Oct 11, 2004.

  1. Peter

    Peter Guest

    UK Model, Sonata V6 / Year 2000

    My car has suddenly lost some power and when pulling away from a
    standing start.

    It exhibits a shuddering which is also noticeable just by revving the
    engine. At over 1500rpm the shudder is barely noticeable but there is
    nevertheless a significant loss of power in the vehicle.

    As a wild guess it seems like some of the cylinders are not operating.

    Can anyone advice on possible fault scenarios?
    Peter, Oct 11, 2004
  2. Peter

    Zotto Guest

    Have Your Sonata TCS? If so, may be it had worked, control if the TCS lamp
    is blinking next time.
    Zotto, Oct 11, 2004
  3. Peter

    Jason Guest

    Any CELs?
    Jason, Oct 11, 2004
  4. Peter

    Peter Guest

    Have Your Sonata TCS? If so, may be it had worked, control if the TCS lamp
    Yes I have TCS and I tried switching it off without any change. But
    the fault exists even if I rev the engine and the car isn't moving.
    Peter, Oct 11, 2004
  5. Peter

    Peter Guest

    Any CELs?

    What are CEL's ?
    Peter, Oct 11, 2004
  6. CEL = "Check Engine Light". IMHO, is great
    when someone busts out a TLA and you say WTF? HTH, HAND!
    Dances With Crows, Oct 11, 2004
  7. Peter

    Budgie Guest

    Blown head gasket?

    Budgie, Oct 11, 2004
  8. Peter

    Peter Guest

    Any CELs?

    There are no indicators lit showing an sign of a problem.
    Peter, Oct 11, 2004
  9. Peter

    Peter Guest

    Blown head gasket?

    Yikes. that's quite serious, no? I have done about 2 hours driving
    with the car in this condition and am now concerned that I may
    seriously damage the engine.

    Is there a simple way to check for a blown gasket? The plugs seem
    really difficult to reach on this engine.
    Peter, Oct 11, 2004
  10. Peter

    hyundaitech Guest

    I don't think I'd jump to any conclusions. So far, it sounds like a
    misfire caused by plugs, wires, or injectors, but you're unable to
    describe it well enough for us to really understand how it feels. How the
    car actually feels will be the number one source of direction for a tech
    that has no other indications. You may want to consider taking it to the
    shop for diagnosis.
    hyundaitech, Oct 11, 2004
  11. Peter

    Peter Guest

    I don't think I'd jump to any conclusions. So far, it sounds like a
    Appreciated! My paranoia was overtaking me. It's a really nice car and
    its engine was so running so sweetly, I just hope I haven't damaged

    The thing is that I am pretty technical but not in the field of modern
    car engines so my diagnostics skills are sparse. I removed one of the
    easily accessible spark leads while the engine was running and noticed
    no audible difference in the engine. Then with the engine stopped I
    looked at the oil and that seemed dark and clear and there were no
    traces of gunky residue on the oil filler cap.

    If you can direct me further with questions I am sure I could locate
    the problem.
    Peter, Oct 11, 2004
  12. Peter

    Rich Guest

    I have the '99 model Sonata (UK) I had similar problems and it was a plug
    lead which I suspected myself, and would normally have replaced myself in
    the past on other cars I've had ,along with the plugs, these are the most
    common causes of a misfire like you describe.

    But one look at what was involved for a novice like me and I took it to the
    local dealer !!
    One word of advice, if it is a lead get them to replace them all.One of
    mine went ,and within 2 months another went, getting at the back ones is
    labour expensive, so you may as well get them all done in one go, cost me
    about 70 quid to get the three back ones done including labour.

    We had bother with the crank sensor too. This involved the car refusing to
    start now and again and erratic tick over speed and juddering, it also used
    to cut out, if you knocked the engine off and restarted it usually sorted
    the fault but it soon returned. Hopefully this is not the problem as this
    was expensive. It does sound more like the plugs or leads though.
    Rich, Oct 11, 2004
  13. Peter

    hyundaitech Guest

    Pull the three leads you can access off the plugs but do not remove them
    from the holes. Place them back on the plugs but do not snap them on.
    Start the car and gradually pull the wire off the plug. If the wire is
    arcing in the hole, you should be able to see it jump through or off the
    plastic as it gets far enough away from the plug to cause the spark to
    jump elsewhere.

    The two main causes of failure are carbon tracking on the outside of the
    plastic and a small hole in the plastic allowing the spark to exit.

    Of course if it's one of the rear cylinders, you are counting on a
    significant job. I figure it's not since you've already found a lead
    which has no effect when pulled. If the others all slow the engine and
    one doesn't, then that's the cylinder you should investigate.

    If you're around 100k kilometers, you should probably replace all the
    plugs and wires.
    hyundaitech, Oct 12, 2004
  14. Peter

    Old Timer Guest

    Could be nothing more serious than a defective plug wire.

    Old Timer, Oct 14, 2004
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