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a c idle

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  • a c idle

    what is keeping my festiva from ideling up when i turn the A C will idle up on cold mornings runs great

  • #2
    probley will help to know what year the car is. Is the AC factory installed, dealer installed, or aftermarket. If you don't know post pictures.


    • #3
      It's a1989 with factory air I changed the oaf but it didn't help any.


      • #4
        carb or efi (automatic?)


        • #5
          it is automatic i have changed the IAC 3 relays by the battery adjusted screw on top of throttle body. my other car would idle up if i turned the rear defog on but this one wont idle up at all. almost kills the car when i turn the ac on. dont know any thing elce to check or do.


          • #6
            89 Carb has Throttle Kicker Solenoid for Electrical load and also one for ac load. I've never owned a carb equipped Festiva.

            89 EFI relies on the VAF, the Idle Speed Control-Bypass Air (ISC-BAP), Throttle Position Sensor and Crankshaft Position Sensor I/O to the ECA to control this.

            Your idle adjustment screw on the throttle body should be adjusted to idle to 830-870 rpm in PARK with the engine warmed up to normal operating temperature and the cooling fan not running. and no other electrical loads (lights, blower, defogger etc.)

            Sounds like you have exchanged all the parts involved except the VAF, TPS and ECA.
            Check for vacuum leaks or clogs in the vacuum hose going to your distributor?
            The 89 distributor is unique but I think the CPS is in it. You would likely have other issues if there was a problem here though.

            Check wiring for good connections, bare wires etc to the sensors involved.

            I'm just throwing out ideas for you to check out.
            Last edited by 1990new; 03-24-2020, 07:55 PM.


            • #7
              Thank you for your help. That's the only thing on the car that don't work and last night I changed the computer and mass air flow. But it didn't do any different so that leaves the tops but that may be a little over my head to mess with.