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Home >> Geo >> 1989 >> Prizm Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Adjustments >> Idle Speed >> Dashpot
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Idle Speed: Dashpot

  1. Ensure idle speed is within specification. See IDLE SPEED under IDLE SPEED & MIXTURE. With engine running, remove cap, filter and separator from dashpot on side of throttle body. See Fig 1 .
    Fig 1: Removing Dashpot Components (Prizm & Prizm GSi)
    G91C16792Courtesy of GENERAL MOTORS CORP.
  2. Maintain engine speed at 3500 RPM (Prizm) or 2500 RPM (Prizm GSi) and plug VTV hole inside dashpot. See Fig 1 . Release throttle and ensure engine speed is 1500 RPM (Prizm) or 1800 RPM (Prizm GSi).
  3. If engine speed is not correct, rotate idle stop screw on throttle shaft until correct engine speed is obtained. With dashpot RPM adjusted, remove plug from VTV hole.
  4. Ensure engine speed returns to correct idle speed in approximately one second. Reinstall dashpot components.
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