Fuel Filler Cap: Description and Operation

FEATURES
The fuel tank filler cap has the following characteristics:

- A vacuum relief valve allows air into the fuel tank to replace the fuel as it is used. The valve opens after a vacuum of -3.4 kPa (-0.5 psi).

- A pressure valve acts as a backup pressure relief valve if the venting system is overpressurized or restricted. The pressure relief range is 11.1-14.4 kPa (1.6-2.1 psi).

- Damage to the fuel tank filler cap or contamination that stops the pressure vacuum valve from working may result in deformation of the fuel tank. Care should always be taken to use a proper fuel tank filler cap in good working order.

- The fuel tank filler cap is a threaded screw-on with a pre-vent feature that allows the fuel tank to vent for the first three-quarter turn before unthreading.

- Fuel tank filler caps are attached to the vehicle with a strap using the fuel tank filler pipe-to-housing screw at the three to four o'clock position.

- The fuel tank filler cap provides vacuum relief functions and should be replaced with the proper pressure / vacuum relief fuel tank filler cap to prevent possible system malfunction.

- The fuel tank filler cap is fitted with a torque-limiting ratchet to ease in removal.