Comanche 2WD L6-242 4.0L VIN S MFI (1992)
Fuel Filler Cap: Description and Operation
Pressure-Vacuum Filler Cap
FUEL FILLER CAP
The fuel filler cap uses a two-way (vacuum and pressure) relief valve that is closed during normal operating conditions. The relief valve is
calibrated to open only when pressure in excess of 1.5 psi or vacuum in excess of 1.8 inch Hg develops in the fuel tank. When vacuum or pressure
is relieved, the valve returns to its normally closed position.
NOTE:
It is normal to encounter an air pressure release when removing the fuel filler cap.
