Wagoneer L6-242 4.0L VIN M FI (1988)
Rollover/Pressure Relief Valve: Description and Operation
Roll Over Valve
The dual function pressure relief/rollover valve, relieves fuel tank pressure under normal operating conditions, and prevents fuel flow to the vapor
canister, through the vent hose in the event of a vehicle rollover. The valve consists of a plunger, spring, and orifice with guide plate, and is mounted on
top of the fuel tank, in a normally open position. In the open position, fuel vapors from the tank travel to the vapor canister. In the event of rollover the
valve becomes inverted and the plunger is forced against the guide plate preventing raw fuel from flowing through the valve orifice into the vent tube.