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    Very unusual idle problem!

    Hello all, i hope this has happened to someone else here on the forum.

    First off, the car was running great for months, but then one day, it developed this idle problem which i could not figure out to this date. I got an H22 with no modifications done to it other than an IM spacer, lightened flywheel, CAI and SS exhaust. The car drives normal, and feels just as powerful as before.


    Problem:

    When i'm driving, and clutch-in to coast to a light or stop, my idle jumps to about 3k for an average of 10 seconds. Sometimes it only jumps up to about 2.5k, and only lasts for a couple seconds. After this, the engine returns to normal idle. If i barely apply any load to the motor (say reversing down a slight incline, and barely releasing the clutch), the idle problem does not arise.

    An additional issue which is not as annoying, is that when the idle is normal, if i peg the gas ever so slightly, the rpms will drop to about 250rpm and then recorrect itself to about 1000rpm, then set back into the 750rpm range.



    Suspicions:

    Prior to this problem, my master cylinder/booster seal broke, allowing fluid to collect in the brake booster. At the time, i didn't know where the fluid was goin, so i just kept topping it. When i decided to get a new master cylinder and install it, i noticed this problem, and pulled about a liter of brake fluid out of the brake booster using a suction hose. It later occured to me that the vacuum line from the booster to the IM could have been drawing small amounts of brake fluid into the IM, and right across from this vacuum fitting is the IACV. Is it possible that brake fluid could have ruined my IACV? and if so, how could i trouble shoot without slapping a different one on?


    Anyways, please help me troubleshoot this annoyance!


    Thanks for all your help in advance!
    90 4Dr.CB7, 416,XXX KMS and still running like a champ!

    #2
    i highly doubt brake fluid would ruin the IACV but id pull it off and check kthe condition of the screen and seals. you can also check the resistance on the electrical plug (i dont have my manual on me right now so i cant give you resistance values.)

    check the throttle cable for free movement, gummed up throttle body and at fully warmed up, pull the electrical connector off the IACV and make sure the idle is set at 650. turn off the motor, plug it back in, start the motor back up and it should return to the factory 750.
    I <3 G60.

    0.5mm Oversized Stainless valves and bronze guides available. Pm me please.

    Comment


      #3
      Is it possible that the lightened flywheel could be causing this problem?

      "The fault-finder will find faults even in paradise. Love your life, poor as it is. You may perhaps have some pleasant, thrilling, glorious hours, even in a poorhouse."-Henry David Thoreau

      Comment


        #4
        kinda ironic, i have a lightened flywheel (13lb) and i also have idle problems but would it be directly related? probably not.
        I <3 G60.

        0.5mm Oversized Stainless valves and bronze guides available. Pm me please.

        Comment


          #5
          wed3k, i have already checked the visual condition of the IACV, cleaned it with rubber safe brake clean, and also made sure the idle was at 650 when the plug was not connected. Still have a problem

          As for a lightened flywheel? i highly doubt it, since i've had my 8lb flywheel installed for over a year with no issues.
          90 4Dr.CB7, 416,XXX KMS and still running like a champ!

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