Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Thermal Vacuum Valve - EVAP: Testing and Inspection
Canister Purge Thermal Vacuum Switch (CP-TVS)
With engine coolant temperature below the calibration point, connect a vacuum gauge to upper port and a vacuum pump to lower port. Apply vacuum,
then disconnect pump. The gauge should indicate that the vacuum is slowly bleeding off. Replace valve if operation is not as specified.
Make some connections as ``Cold Check'', then with engine coolant temperature above the calibration point, apply vacuum. Vacuum gauge reading
should be the same as that applied with vacuum pump. Disconnect vacuum pump from valve. The vacuum reading on the gauge should drop to zero
immediately. Replace valve if operation is not as specified.
