Fuel Tank: Description and Operation
Fuel Tank and Lines
Fuel Tank Assembly
The fuel tank is located on the right hand side of the vehicle, between the transmission and the right hand chassis longitudinal. The tank is located on a mounting cradle which secures the whole fuel tank assembly to the vehicle. The tank has a useable capacity of 88.1 liters (23.2 US gallons).
The cradle is attached to the chassis with six screws. When the cradle is attached to the chassis, the tank is positively secured via foam pads which bear against the central chassis cross beam. A protective cover is fitted to the front right hand corner of the tank and provides additional protection.
The fuel tank is manufactured from moulded plastic which is a minimum of 3 mm thick. The tank is a sealed unit with the only internal access being via the pump module flange aperture on the top of the tank.
The flange assembly comprises a pump module flange which contains all external pipe and electrical connections for the tank internal components, a collar and a clamp. The flange is fitted with a seal which locates in the tank aperture. An arrow on the flange must be aligned between two moulded lines on the tank, adjacent to the pump module flange aperture, to obtain the correct orientation. The collar is located over the flange and is secured with the clamp. The flange, seal, collar and clamp arrangement meets the sealing requirements of LEV2 emissions.
The flange has a five pin external connector which provides for electrical connections for the level sensors, a common ground for the sensors and the fuel pump. This connector is wired to three push fit connectors on the underside of the flange. A quick release connector provides for the connection of the fuel feed pipe and breather.
A tank carrier assembly is attached inside the tank and is used to locate the internal tank components. The carrier provides location for the front and rear level sensors, the Roll Over Valves (ROVs) and the front jet pump.
The fuel pump module is mounted on a bayonet fitting at the base of the fuel tank. The module locks into position by rotating the module clockwise into the bayonet. The module comprises the fuel pump, the rear jet pump, the pump inlet filter, a second fine mesh filter which mounts into the carrier and an over pressure valve (PRV). The pump module, fuel filter and level sensors are available as serviceable components, the individual assembly components are not available separately.
Fuel Tank Internal Components
The 4.2L V8 supercharged vent system comprises:
^ Four Roll Over Valves (ROV)
^ One Fuel Level Vent Valve (FLVV)
^ One Liquid Vapor Separator (LVS)
The vent system is mounted on the fuel tank internal carrier which is assembled outside of the tank and inserted into the tank during the blow moulding process. None of the internal tank venting components are serviceable.
The two rear ROVs are mounted directly onto the LVS with rubber grommets and secured with clips.
The two front ROVs are located in the front of the tank and are attached to the main beam of the carrier by a moulded clip. Both ROVs are connected to the LVS with a plastic corrugated tube.
The four ROVs vent directly into the LVS. Any liquid fuel is separated from the vapor in the LVS and drains back into the tank via the FLVV. The LVS is connected by a corrugated tube to the fuel pump module flange. This allows fuel vapor to exit the tank.
The main purpose of the FLVV is to control the fill volume of the tank. During filling, vapor is passed via the FLVV to the LVS. The vapor then passes from the LVS to the fuel pump module flange vent connection via a corrugated tube. The flange vent connection is connected to the charcoal canister which stores the fuel vapor. During filling, when the tank reaches its full level, the FLVV closes and prevents fuel vapor passing through to the LVS. This causes the pressure in the tank to rise which in turn causes the pump filling nozzle to turn off.