Fuel Filler Cap: Description and Operation

The plastic/metal Fuel Filler Cap is installed with a 1/4 turn onto the end of the fuel filler tube. Its purpose is to retain vapors and fuel in the fuel tank.

The Fuel Filler Cap incorporates a two-way relief valve that is closed to atmosphere during normal operating conditions. The relief valve is calibrated to open when a pressure of 172 mbar (2.5 psi) or vacuum of 20 mbar (8 inH2O) occurs in the fuel tank. When the pressure or vacuum is relieved, the valve returns to the normally closed position.

WARNING: REMOVE THE FUEL FILLER CAP IN ORDER TO RELEASE FUEL TANK PRESSURE BEFORE DISCONNECTING ANY FUEL SYSTEM COMPONENT.