Fuel Delivery and Air Induction: Description and Operation

Air Induction





Filtered air from the vehicle's intake ducting is metered by the electronic throttle and then directed via the induction elbow into the intake manifold. The electronic throttle enables the ECM to control the flow of air into the engine.





The induction elbow provides the interface between the electronic throttle and the intake manifold.

There are connections on the induction elbow providing vacuum take-offs for brake servo, cruise (speed) control actuator/fuel pressure regulator and the EVAP system part-load breather. The EGR valve is also connected to the induction elbow or, if not used, a blanking plate is fitted.


Fuel Delivery






Fuel is stored in the fuel tank mounted across the vehicle behind the passenger compartment bulkhead. Fuel pumped from the tank enters a feed pipe at the rear of "B" bank. Fuel flow is along the 'B' bank fuel rail, across the top front of the engine (cross-over pipe) and through the "A" bank fuel rail, the unused fuel returning to the tank by a pressure regulator. Fuel-rail pressure is regulated at 3.0 bar above intake manifold pressure.

Eight fuel injectors, controlled by the ECM are installed in the fuel rails on each side of the intake manifold. The fuel rails which run the length of each cylinder bank and are integral with the air intake manifold.

The amount of fuel injected into the engine is controlled by the ECM.

A cross-over pipe connects the two fuel rails together at the front of the manifold.

A test valve in the cross-over pipe allows the fuel rail to be pressurized and de-pressurized during the servicing and troubleshooting procedures.

A pressure regulator on the rear of the right fuel rail controls the pressure in the fuel rails.

A return line directs excess fuel from the pressure regulator back to the fuel tank.