Fuel Filler Cap: Description and Operation

Fuel Filler Cap:

PURPOSE
The fuel fill cap is used to prevent fuel spill and close the evaporative/fuel system to the atmosphere. It also serves as the source at which the evaporative emission service kit can be attached to check evaporative emission system leakage.

FEATURES
The fuel tank filler cap is a sealed cap with a built-in pressure-vacuum relief valve, and:

- Fuel system vacuum relief is provided after negative 2 kPa (0.28 psi).

- Provides pressure relief above 14 kPa (2 psi).

- Under normal operating conditions, the fuel tank filler cap operates as a check valve, allowing air to enter the fuel tank, as fuel is used, while preventing fuel vapors from escaping the fuel tank through the fuel tank filler cap.

- is an indexed design with a 1/8 turn on-off feature for positive installation.

- is attached to the vehicle with a strap using the fuel tank filler pipe-to-housing bolt nearest the six o'clock position on sedans and the two o'clock position on wagons.

- provides proper sealing functions and vacuum relief functions.

- should be replaced with the proper fuel tank filler cap to prevent possible system malfunction.

When removing or installing the fuel tank filler cap. turn the handle portion of the cap 1/8 turn in the proper direction as shown on the cap and install or remove the cap straight up or down.