LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 1981 >> Hi-Cube Standard Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Evaporative Emissions System >> Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Evaporative Emissions System: Testing

  1. With engine cold, position transmission in "NEUTRAL" or "PARK" and apply parking brake. Start engine and observe movement of actuator rod and exhaust heat valve. Valve should move to its closed position.
  2. If valve does not close, disconnect hose at actuator and check for vacuum. If there is vacuum, replace actuator. If no vacuum is found, disconnect hose at TVS-to-vacuum source. If there is vacuum at hose, replace TVS. If no vacuum, check hose for leaks.
  3. When coolant temperature reaches 180°F (V8) or oil temperature reaches 150°F (6 cylinder), exhaust heat valve should move to the 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.
scientia non olet · About LEMON Manuals