Fuel Tank: Description and Operation

FUEL TANK




The fuel tank is blow-molded of high-density polyethylene. This material is multi-layer in construction to enhance its ability to minimize leakage of fuel vapors to the atmosphere (impermeability). It is generally 4.0 mm to 5.0 mm (101.6 in. to 127 in.) in thickness and incorporates two valves which operate during the refueling process.

Both these valves are not serviceable, both are molded into fuel tank shell, Fill Limit Vent Valve (FLVV), and grade vent valve.

Fill Limit Vent Valve (FLVV) - Located on the top, front surface of the fuel tank, next to the fuel pump module. This is a buoyant float type valve which controls the flow of fuel vapor into the EVAP canister during refueling. The operation of the valve controls fuel tank capacity during the refueling process (refer to "Theory of Operation-ORVR"). The valve also prevents liquid fuel from escaping if the vehicle is involved in a roll-over accident.

Grade Vent Valve - Located just rear of the FLVV. This valve's primary function is to provide a vent path for fuel vapors when the tank is full. It also prevents liquid fuel from escaping the fuel tank if 1) the vehicle is operated or parked on an incline or 2) the vehicle is involved in a roll-over accident.