Fuel Pressure Sensor: Service and Repair

WM 240919 Removing and installing fuel pressure sensor (high-pressure sensor)

Preliminary work

1. Pull out the fuse for the fuel pump or disconnect the battery. This prevents the fuel pump from starting when the door is opened.
2. Remove intake-air distributor. -> 244619 Removing and installing intake-air distributor Overhaul

Information

Component overview





Fuel distributor pipe





Removing high-pressure sensor (rail pressure sensor)

WARNING

Toxic substances

- Danger of poisoning or suffocation

-> Ventilate the work area well.
-> Never ingest or inhale.
-> Read specific information on the Hazard Sheet.
-> Wear personal protective gear.

WARNING

Highly inflammable or explosive materials

- Danger of fire or explosion

-> Avoid contact with hot parts or sources of ignition.
-> Use suction to remove ignitable vapours.
-> Attach warning sign in a clearly visible position.

NOTICE

Dirt on injection system components (intake manifold injection and direct fuel injection system)

- Material damage
- Rough-running engine
- Bad exhaust emissions

-> Thoroughly clean connection points and adjacent areas before loosening them. If the engine is very dirty, wash it before starting disassembly work.
-> Lay removed parts on a clean surface and cover them. Do not use fibre-shedding cloths.
-> Carefully cover components or seal them if repair work will not be carried out immediately. Place rubber caps on connections. Seal intake openings with film or adhesive tape.
-> Only install clean parts. Do not take spare parts out of the packaging until just before installation.
-> Never use compressed air when the system is open. Do not move the vehicle.

WARNING

Leaking fuel supply lines

- Emerging fuel
- Risk of fire

-> Perform leak test.

Information

- Do not bend high-pressure lines. Always remove the high-pressure distributor pipe and other fuel-supply components in the high-pressure area completely. Check that the connection points are not damaged and are perfectly clean and make sure there is no thread damage. Fit union nuts on all connection points by hand before screwing in screws or bolts. Remove dirt on the conical/ball joints. Check connection points for leaks following fitting.

Information

- The ignition must be switched off when working on the fuel system.

- Absorb any escaping fuel using a suitable binding material or a cloth.

- Cloths which have absorbed fuel must be disposed of according to the applicable national laws.

- The fuel system must be depressurised before starting work on it.

- Only work on the fuel system in well-ventilated rooms.

- Any seals which have been removed must always be replaced.

1. Pull off cable plug for high-pressure sensor. -2-





High-pressure fuel distribution

2. Place a cloth around the high pressure sensor. Relieve fuel pressure at fuel distributor pipe (rail) by slowly opening the high pressure sensor using a ring wrench.
3. Remove high pressure sensor. Visually check the thread and sealing ball to make sure they are not damaged.

Installing high-pressure sensor (rail pressure sensor)

Information

- The tightening specifications for the basic engine are stored centrally. -> 1001IN Tightening torques, tightening sequences, assembly overviews [1][2]Specifications. Tightening torques and assembly instructions for other assemblies (e.g. chassis, electrics, transmission or body) or for peripheral engine equipment can be found in the corresponding documents.

1. Visually check the thread and sealing ball on the high-pressure sensor to make sure they are not damaged.
2. Visually check the threaded bore and sealing cone on the high pressure distributor pipe (rail) to make sure they are not damaged.
3. As in the leak test, blow fuel residues out of the high-pressure distributor pipe by blowing helium through the opening in the high-pressure sensor. For details, see -> 243001 Checking fuel distributor pipe for leaks Testing and Inspection
4. Fit the high-pressure sensor. -2-
4.1. Carefully screw the high-pressure sensor by hand into the thread of the fuel distributor pipe. Check that it screws in easily.
4.2. Tighten the high-pressure sensor.





High-pressure fuel distribution

5. Connect cable plug to the high-pressure sensor. -2-
6. Check high-pressure distributor pipe for leaks. -> 243001 Checking fuel distributor pipe for leaks Testing and Inspection

Subsequent work

1. Fit the fuse for the fuel pump or connect the battery.
2. Fit intake-air distributor. -> 244619 Removing and installing intake-air distributor Overhaul
3. Fill and bleed the fuel high-pressure system. -> 2430B1 Filling and bleeding the fuel distributor pipe Service and Repair