Fuel delivery system - V8 (Description): Description and operation

Description

General

The fuel delivery system comprises a fuel tank, fuel pump and regulator and eight injectors. The system is controlled by the Engine Control Module (ECM) which energises the fuel pump relay and controls the operation and timing of each injector solenoid. ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine management.

The multiport fuel injection system is a returnless system with the fuel pressure maintained at a constant level by a fuel pressure regulator. The regulator is located in the fuel pump housing and returns excess fuel directly from the pump to the tank.

An electrically operated fuel pump is located in the top of the fuel tank and supplies fuel at pressure to two fuel rails via a flexible hose. The hose is attached to the feed pipe on the fuel rail at the rear of the engine and the fuel pump with sealed quick release couplings.

A moulded fuel tank is located at the rear underside of the vehicle between the chassis longitudinals. The tank provides the attachment for the fuel pump and fuel gauge sender unit which is located inside the tank. The fuel system is pressurised permanently with pressurised fuel vapour venting to an EVAP canister. EMISSION CONTROL - V8, DESCRIPTION AND OPERATION, Emission Control Systems.

Fuel tank and breather

The fuel tank and breather system is a major part of the fuel delivery system. The fuel tank and breathers are located at the rear of the vehicle between the chassis longitudinals.

Fuel tank The moulded fuel tank is made from High Molecular Weight (HMW) High Density Polyethylene (HDPE). Continuous layers of nylon additive are used during the moulding process. The nylon layers give an improved limit of fuel permeation through the tank wall and are also resistant to alcohol based fuels used in the NAS market.

The tank is retained in position by a metal cradle which is secured to the chassis with two nut plates and bolts at the rear and a stud plate and two nuts at the front. A strap above the tank is bolted to the chassis and restrains the tank from moving upwards. The fuel tank has a useable capacity of approximately 95 litres (25 US Gallons).

An aperture in the top surface of the tank allows for the fitment of the fuel pump, regulator and fuel gauge sender unit which is retained with a locking ring.

A reflective metallic covering is attached to the tank with two scrivets to shield the tank from heat generated by the exhaust system.

The fuel filler is located in the right hand rear quarter panel, behind an access flap. The flap is opened electrically using a switch on the fascia.

The filler is closed by a threaded plastic cap which screws into the filler neck. The cap has a ratchet mechanism to prevent over tightening and seals against the filler neck to prevent the escape of fuel vapour. The filler cap has a valve 2

which relieves fuel pressure to atmosphere at approximately 0.12 to 0.13 bar (1.8 to 2.0 lbf.in ) and opens in the 2

opposite direction at approximately 0.04 bar (0.7 lbf.in ) vacuum.

All markets except NAS: A moulded filler tube, made from HMW HDPE with no additional additives, connects the filler to the tank via a flexible rubber hose. The filler tube is connected at its top end behind the filler flap.