Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Evaporative Emission Control Canister: Description and Operation
Vapor Storage Canister
Canister Purge Thermal Vacuum Switch (CP-TVS)
When coolant temperatures are below the switching point, canister purge is controlled by the internal orifice within the switch. However, when coolant
temperature is above the switching point, the switch opens and permits canister purge to be controlled by manifold vacuum from the carburetor port.
EGR Canister Purge Thermal Vacuum Switch (EGR-CP-TVS)
When engine coolant temperature is below the calibration point of the switch, ported vacuum is blocked from the canister and the EGR valve. Above
the switching point, ported vacuum is directed to both the canister purge port and the EGR valve.
