Bad vibration at idle when AC compressor kicks in

Discussion in 'General Motoring' started by techman41973, Jun 6, 2005.

  1. techman41973

    techman41973 Guest

    I have a 97 accord EX. When sitting in the car with the engine idling,
    the whole car starts to shake and vibrate when the AC compressor kicks
    in. The engine normally idles at about 7500rpm. When the AC compressor
    kicks on, the RPM drops which causes the shaking. Is it simple to have
    a mechanic raise the idle speed of the engine a bit? Anyone else
    experience this problem with 94-97 accords? Thanks
    techman41973, Jun 6, 2005
  2. techman41973

    Brian Guest

    That happened to me once (actually to someone whose car I was looking at for
    the same problem). The AC compressor was seizing up, the belt caught on
    fire shortly thereafter, lots of smoke...

    Probably there's a similar reason why your car is telling you it needs help,
    quickly...but maybe not. 750 rpm, not 7500 I presume...

    Brian, Jun 6, 2005
  3. techman41973

    Professor Guest

    There is a mechanism to kick the idle when the compressor load comes
    on. The idle should stay about constant. However, Brian may be right
    that your compressor may be binding. You need to loosen the compressor
    belt and rotate the compressor manually to check for excessive

    Professor, Jun 7, 2005
  4. Turning the compressor by hand might not tell you anything. If the
    clutch doesn't engage when the engine isn't running, the pulley will
    turn free even if the compressor is seizing.

    I'd have the shop check out the idle control. Engines shake when they
    are lugged below their normal idle speed, which sounds like the symptom
    Paul Hovnanian P.E., Jun 7, 2005
  5. techman41973

    SoCalMike Guest

    how new are the plugs, wires/rotor/distributor cap? new plugs may help
    the rough idle. you shouldnt have to actually touch the idle speed
    setting, doing so just masks the symptoms.
    SoCalMike, Jun 7, 2005
  6. techman41973

    twillmon Guest

    And remember to turn the AC on or you will only be testing the clutch
    for binding. (Better remove the belt for this test.)

    Tom Willmon
    near Mountainair, (mid) New Mexico, USA

    Did you ever stop to think, and then forget to restart?

    Net-Tamer V 1.12.0 - Registered
    twillmon, Jun 7, 2005
  7. techman41973

    Professor Guest

    What I had in mind was turning the compressor... not just the pulley. I
    would get a socket that fit the nut on the pulley and turn the
    compressor shaft to detect any binding.

    Professor, Jun 9, 2005
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