Fuel delivery system - K Series 1.8 (Fuel Pump): Description and operation

The fuel tank is located on the underside of the vehicle, forward of the rear suspension subframe. The tank is constructed from moulded plastic and is retained by a tubular cradle which is secured to the vehicle floorpan with four bolts. The fuel tank has a capacity of 60 litres (13.2 gallons).

A reflective metallic heat shield protects the tank from heat generated from the exhaust system on the LH side and a fire shield is located on the RH side.

An aperture in the top surface of the tank allows for the fitment of the fuel pump. The pump is secured with a special locking ring and is sealed with a rubber O-ring seal.

The fuel tank filler is located on the right hand rear wing panel and is protected by a lockable cap. The plastic tube from the filler is connected to the tank by a flexible rubber tube and secured with clamps. A vent pipe is connected to the neck of the filler to allow air and fuel vapour displaced from the tank when filling to vent to atmosphere via the filler neck. A smaller vent pipe is also connected to the tank and vents fuel vapour from the tank to the EVAP canister which is located in the RH wheel arch, behind the liner. EMISSION CONTROL - K SERIES 1.8, DESCRIPTION AND OPERATION, Description.

The tank incorporates Roll Over Valves (ROV) to allow vapour in the tank to escape to the EVAP canister. The tank must not be over-filled to maintain a vapour space above the fuel level and allow the tank to 'breathe'. The ROV's are welded onto the top surface of the tank and connected via a pipe to the EVAP canister. During normal operation each ROV is open allowing vapour to pass to the canister. In the event of the vehicle being overturned the ROV's shut-off, sealing the tank and preventing fuel flowing down the vent pipe.

Fuel Pump

The fuel pump is electrically operated and is 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. The fuel pump is housed in a plastic body which incorporates coarse and fine filters. The fine mesh filter should be renewed at the prescribed service intervals. The fuel pump is located in a larger housing which is the swirl pot. The swirl pot maintains a constant fuel level at the pump pick-up.

A pressure regulator which regulates the pressure output of the pump to 3.5 bar (51 lbf.in²) is located in the pump housing. If the pressure exceeds this setting the regulator relieves excess pressure back to the swirl pot. This ensures that the fuel rail and the injectors are supplied with a constant pressure.

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 which supplies power and ground for 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 prevents fuel draining from the feed pipe into the tank after the pump has stopped.

Injectors

Four injectors are held between the fuel rail and the inlet manifold. The injectors are sealed to the fuel rail and the inlet manifold by O-ring seals. Each injector supplies one cylinder with fuel. The injectors receive pressurized fuel from the fuel pump via the fuel rail. The Engine Control Module (ECM) is responsible for the timed injection duration of each injector. The injectors supply a finely atomized spray of fuel into the cylinder which is mixed with the air prior to ignition. Refer to Engine Management System - MEMS for further details. ENGINE MANAGEMENT SYSTEM - MEMS, DESCRIPTION AND OPERATION, Description.

Fuel Rail

The fuel rail is located at the rear of the engine and secured to the inlet manifold with two bolts. The four injectors are located in holes in the rail, sealed with O-ring seals and secured with spring clips. The location of the fuel rail secures the injectors between the rail and the inlet manifold.

A flange with two threaded holes on the LH end of the fuel rail provides attachment for the fuel feed pipe. The fuel feed pipe has a metal flanged end which is locates on the fuel rail. A seal prevents leakage and the flange is secured with two screws. An accumulator is located on the RH end of the fuel rail.

Accumulator

The accumulator is attached to the right hand end of the fuel rail. The accumulator acts as a damper to damp pulses from the pump and ensure that the fuel pressure in the rail and to the injectors is constant. The accumulator is connected by a pipe to the inlet manifold from which it receives a vacuum to aid the damping process.