BMW X5 Owners & Service Manuals

BMW X5: Fuel Pump With Drive

NOTES ON FUEL PRESSURE CHECK (REFERENCE PRESSURE: ENVIRONMENT)

Feature of this version with ambient pressure:

The connection for the vacuum hose of the fuel pressure regulator is located between the throttle and the air cleaner or on the air cleaner.

Test precondition:

The correct fuel pressure regulator is fitted.

Description of operation:

The control function of the fuel pressure regulator must be guaranteed under all operating conditions. The fuel pump must always be able to generate a higher fuel pressure than the pressure regulated by the pressure regulator.

The injection rate is adjusted by means of the injection time; the injection time is controlled by the DME.

Description of operation: fuel return line

When the engine is at a standstill and the ignition key is in position 0, the fuel return line after the pressure regulator is at zero pressure.

Description of operation: pressure retaining function

The pressure regulator closes when the engine is at a standstill and the ignition key is in position 0. The fuel pressure in the delivery line is retained over an extended period. A non-return valve closes in the fuel pump.

These measures help to retain the fuel pressure in the fuel system. Extended starting times are thus avoided.

Complaint: drive characteristic faults, lack of power

If the measured value is less than the nominal value - 0.2 bar:

or

If the measured value is greater than the nominal value + 0.2 bar:

If no kinks are visible:

If measured value remains too high, then pressure regulator is in all probability faulty.

IMPORTANT: With less likelihood, the return line may be completely blocked. When the pressure regulator is removed, fuel could escape under pressure!

Complaint: starting problems

Special tool 13 3 010 (hose clamp) is required for the following test.

If the measured value has dropped by more than 0.5 bar:

If the measured value has now dropped by less than 0.5 bar, the following faults can be present:

Check components. Replace faulty components.

If the measured value has dropped by more than 0.5 bar again:

NOTE:

CHECKING FUEL PUMP DELIVERY PRESSURE (N52K)

Special tools required:

IMPORTANT: The fuel in the fuel lines is under pressure (approx. 5 bar)! Catch and dispose of escaping fuel.

Necessary preliminary tasks:

Remove dust cap (1).

Connect special tool kit 13 5 220 (comprising 13 5 221 and 13 5 222) to pressure sensor of DIS Tester.

Connect pressure sensor to DIS Tester.

Fuel Pump With Drive
Fig. 1: Identifying Non-Return Valve On Special Tool (13 5 220)

IMPORTANT: Do not under any circumstances screw in the check valve up to the mechanical stop. This could damage the valve in the pressure regulator housing.

Mount special tool kit 13 5 220 to injection tube and tighten knurled nut hand-tight.

Screw out check valve (1) so that valve in pressure regulator housing is closed.

Start engine.

Screw in check valve (1) until a pressure reading is indicated on DIS Tester.

Measuring fuel pressure:

Compare actual value of test pressure with specified value.

NOTE: Removing special tool kit 13 5 220:

NOTE: Read out fault memory of DME control unit. Check stored fault messages. Now clear the fault memory.

Fuel Pump With Drive
Fig. 2: Identifying Special Tool (61 3 050)

Installation:

Now clear the fault memory.

READ NEXT:

 Fuel Filter

REPLACING FUEL FILTER (M57T2) Necessary preliminary tasks: Switch off ignition Remove rear assembly underside protection Recycling: Catch and dispose of escaping fuel. Observe country-specific wa

 Injection Nozzle And Lines

REPLACING COMPLETE INJECTION PIPE (N52/ N52K) Special tools required: 13 5 281 Necessary preliminary tasks: Read out fault memory of DME control unit Switch off ignition Remove clean air pipe

 Throttle And Operation

REMOVING AND INSTALLING/SEALING THROTTLE VALVE ASSEMBLY (N52 / N52K / N51 / N53) Read and comply with notes on protection against electrostatic damage (ESD protection). Necessary preliminary tasks:

SEE MORE:

 Thermostat And Connections

REMOVING AND INSTALLING/REPLACING COOLANT THERMOSTAT (N52K) WARNING: Danger of scalding! Only perform this work after engine has cooled down. Recycling Catch and dispose of drained coolant in a suitable container. Observe country-specific waste-disposal regulations. IMPORTANT: Protect plug connecti

 Removing And Installing/Replacing Eccentric Shaft (N52K)

Special tools required: 11 4 481 Necessary preliminary tasks: Remove cylinder head cover Remove intermediate lever If necessary, move eccentric shaft (1) on twin surface to minimum lift (2). Fig. 218: Eccentric Shaft NOTE: All bearing caps (1 and 2) of eccentric shaft are marked with number

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