BMW X5 Owners & Service Manuals

BMW X5: N52KP And N51 Fuel System

The N52KP and N51 engine continue to use the conventional "manifold injection" system carried over from the N52. The fuel supply components are also carried over with regard to the EKP module, fuel pump etc.

Engine Service Information
Fig. 50: Identifying Fuel Supply System

N54 Engine

The N54 engine uses the new High Precision Injection (HPI) system. The HPI system is a "direct" fuel injection system which represents the second generation "DI" system from BMW. The first generation was on the N73 engine from 2003.

The N73 engine used a "wall guided" method of injection which used a recess in the piston to aid in mixture formation. The HPI system on the N54 uses a "spray guided" process which allows the mixture to form and ignite without the aid of any "walls" (i.e piston, cylinder wall etc.).

The spray guided system allows for more efficiency by cooling the cylinder charge without excessive cooling of the associated engine components. The wall guided system cools the piston crown which reduces thermal efficiency.

The HPI system also uses the new "piezo-electric" fuel injectors which are a vital components of the spray guided process. These new injectors open in an outward direction, which forms a precise tapered spray pattern.

With the aid of high system pressure (200 bar), the HPI system is now capable of providing new levels of efficiency which were not achievable with previous manifold injection systems.

Engine Service Information
Fig. 51: Identifying Manifold Injection Systems

Engine Service Information
Fig. 52: Identifying HPI Function Systems


 HPI Function

The fuel is delivered from the fuel tank by the electric fuel pump via the feed line (5) at an "feed" pressure of 5 bar to the high pressure pump. The feed pressure is monitored by the low-pressure

 Limp-Home Mode

If a fault is diagnosed in the system, such as e.g. failure of the high-pressure sensor, the fuel-supply control valve is de-energized; the fuel then flows via a so-called bypass into the rail. In t

 Piezo Fuel Injectors

It is the outward-opening piezo-injector that renders possible spray-directed direct injection and thus the overall innovations of the N54 engine. Due to the fact that only this component ensures th


 Rear Light Cluster

REPLACING SOCKET HOUSING FOR LEFT OR RIGHT REAR LIGHT WARNING: Follow instructions for handling light bulbs (exterior lights). Rear light in side panel: Remove flap in luggage compartment trim panel. Turn socket housing and pull out of rear light. NOTE: Bulb, adaptive brake light Bulb, reversin

 Drive readiness

Principle Turning on drive-ready state corresponds to starting the engine. General information Some functions, such as DSC Dynamic Stability Control, can only be used with drive-ready state switched on. Safety information DANGER If the exhaust pipe is blocked or ventilation is insufficient, harmful

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