AC drops idle speed too much

Discussion in 'General Motoring' started by Cameo, Jul 11, 2010.

  1. Cameo

    Cameo Guest

    The extra load of my '94's Accord's AC often causes such a drop in idle
    speed that the engine dies when trying to start up after a traffic light
    change, especially on a slight uphill. This forces me to turn off AC
    when stopping at traffic lights and turn it on again after moving.
    Without AC the idling RPM is about 750, which is about normal.

    Isn't the car's computer supposed to compensate for the AC load?
     
    Cameo, Jul 11, 2010
    #1
  2. Cameo

    Tegger Guest


    Yes. That's the A/C Idle-Up signal.

    From what I see in the various shop manuals, failure to idle-up is usually
    due to a corroded or internally-broken wire between the compressor, the
    compressor clutch relay, and the ECU.

    The ECU sees the A/C signal from the wiring, then boosts idle to
    compensate. If that signal never comes in, the ECU will not know to
    increase idle.
     
    Tegger, Jul 11, 2010
    #2
  3. Cameo

    Cameo Guest

    Thanks. This info at least gives me a leg up when I talk to my mechanic
    about this problem and see if he also knows about it.
     
    Cameo, Jul 11, 2010
    #3
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