lemon-mirror:
Home >> GMC >> 1989 >> Forward Control 6.2 J, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Early Fuel Evaporation System >> System Testing

System Testing

  1. With engine cold, position transmission in "N" or "P" and apply parking brake. Start engine and observe movement of actuator rod and exhaust heat valve. Valve should move to closed position.
  2. If valve does not close, disconnect hose from actuator and apply 10 in. Hg vacuum to actuator. Valve should close and stay closed. If valve does not stay closed, replace actuator. Check valve rod and valve for proper operation. Repair as necessary.
  3. When engine temperature reaches 105°F (40°C), exhaust heat valve should move to open position.
  4. If valve does not open, disconnect hose at actuator and check for vacuum. If there is vacuum, replace TVS. If no vacuum is present, replace actuator.
· About lemon-mirror