Fuel delivery system - K Series KV6 (Fuel Pump): Description and operation

Fuel Pump

The fuel pump is a submersible electric pump located in the top face of the fuel tank. A notched locking ring retains the fuel pump in the tank and requires a special tool for removal and installation. An access panel below the rear passenger seats provides access to the fuel pump for maintenance. The top face of the fuel pump has an electrical connector with power and ground connections to the pump and the fuel gauge rotary potentiometer. A quick fit coupling provides attachment for the fuel feed pipe. A non return valve in the pump outlet prevents fuel draining from the feed pipe back into the tank when the pump is stopped.

The fuel pump is housed in a plastic body which incorporates a coarse mesh filter and a serviceable fine mesh filter. The bottom part of the body forms a swirl pot which maintains a constant fuel level at the pump pick-up. A pressure regulator in the pump body ensures that the fuel rail and the injectors are supplied with fuel at a constant pressure of 3.5 bar (51 lbf/in²). The regulator relieves excess fuel from the pump outlet back to the swirl pot.

Fuel Rail

Three fuel injectors are installed in each inlet manifold and connected to the fuel rail. The injectors are sealed in the fuel rail and the inlet manifolds by 'O' ring seals. A quick release coupling connects the feed pipe from the fuel tank to the fuel rail.

An accumulator is attached to the fuel rail, to damp out pressure pulses from the pump and ensure that the pressure in the fuel rail is constant. On all except NAS vehicles, a vacuum pipe connects the accumulator to the inlet manifold to aid the damping process.

A Schraeder valve is installed in the 'fuel return' pipe (on all except NAS vehicles) or above the accumulator (on NAS vehicles) to provide a pressure test connection for maintenance.