Need help and FAST!!!! 92 gmc 5.0L

Discussion in 'Troubleshooting & Diagnosis' started by bigblock665, Dec 10, 2010.

  1. MrAzzhat2U

    MrAzzhat2U Veteran Member Lifetime Gold Member

    1,392
    6
    Jan 31, 2000
    Lewes DE
    Just take the screws out of it and rotate it by hand without moving the throttle.No need to remove it.
     
  2. AKohler883

    AKohler883 Veteran Member

    799
    1
    Oct 16, 2009
    Reading, PA
    dumb question ... what is an IAC ?

    I have a 92 C1500 with a 305 that is acting up ... I need to start from square one I guess.
     
  3. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

    8,698
    1
    Sep 20, 2004
    Southern Maryland
    idle air controller. It's a vacuum leak controlled by the ECU to perform throttle follower routines during driving to aid in emissions control and driveability, and to regulate idle speed when you're stopped to compensate for temperature, load, engine wear, and whatnot.
     
  4. AKohler883

    AKohler883 Veteran Member

    799
    1
    Oct 16, 2009
    Reading, PA
    how does that differ (in operation) from a Throttle Position Sensor ?
     
  5. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

    8,698
    1
    Sep 20, 2004
    Southern Maryland
    TPS is a variable resistor that, fed with a reference voltage (5v) through the resistor, tells the ECU what throttle angle you're operating at, while the IAC is a stepper motor that is commanded to bleed air into the engine to control speed.
     
    Last edited: Dec 20, 2010

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