Contour L4-122 2.0L CNG DOHC VIN Z SFI (1996)
Rollover Valve: Description and Operation
Vapor Vent
The evaporative emission valve:
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Makes use of a small orifice and shutoff valve that tends to allow only fuel vapor, not liquid, to pass through the evaporative emission return
tube to the evaporative emissions canister.
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Mounts directly to the fuel tank, using a rubber grommet.
The vapors flow through a single vapor tube to the evaporative emissions canister at the rear of the vehicle. A spring-loaded valve provides relief ahead
of the orifice to the evaporative emissions canister. This valve gradually opens above 5-6 kPa (0.7-0.9 psi) to vent fuel vapors from the fuel tank to the
evaporative emissions canister.
The valve also serves as a rollover valve, preventing liquid fuel from entering the evaporative emission canister in the event of a vehicle rollover.
