Diesel MFI Pump: Service and Repair

High Pressure Pump Overview

Follow the points below to avoid running the high pressure fuel pump dry (very low tolerances) and to start the engine quickly after replacing the components:

• If the fuel system components between the fuel tank and high pressure fuel pump are removed or replaced, then a fuel first filling must be performed.

• It is necessary to bleed the fuel system before starting the engine for the first time if the fuel pump, the fuel line (between the fuel tank and the fuel high pressure pump) or the fuel filter were removed.

• If the fuel high pressure pump was removed or replaced, then bleed the fuel system before starting the engine for the first time.

Fill the fuel tank after installing the high pressure pump. Refer to => [ Fuel Tank, Filling with Fuel after Installing High Pressure Pump ] General Information.






1 Bolt

• M6: 9 Nm

• M8: 23 Nm

2 High Pressure Pump Bracket

3 Bolt

• 9 Nm

4 Protective Plate

5 High Pressure Line Union Nut

• Tightening specification, refer to => [ High Pressure Lines, Installing ] High Pressure Lines, Installing

6 High Pressure Pump

• Perform the following points before installing the toothed belt:

• Align the crankshaft Top Dead Center (TDC).

• Stop the high pressure pump toothed belt using the locking tool (T40135). (Do not allow the toothed belt to swing!).

• The high pressure pump must be filled with fuel before starting the engine for the first time. Do not let the high pressure pump run dry. Refer to => [ Fuel Tank, Filling with Fuel after Installing High Pressure Pump ] General Information.

• Follow the guidelines for a clean working environment when working on the fuel system. Refer to => [ Clean Working Conditions ] Clean Working Conditions.

• The adaptation values must be adapted after replacing the high pressure pump or the fuel pressure regulator valve (N276) "Guided Functions" in vehicle diagnostic tester.

• Remove the high pressure pump toothed belt using the puller (T40064).

• Removing and installing, refer to => [ High Pressure Pump ] High Pressure Pump

7 Hose Clamp

• Only use standard production hose clamps, refer to the Parts Catalog

8 Fuel Supply Hose

9 Fuel Return Hose

• The fuel return line must not be bent, damaged or plugged

10 Hose Clamp

• Only use standard production hose clamps, refer to the Parts Catalog

11 High Pressure Line Union Nut

• Tightening specification, refer to => [ High Pressure Lines, Installing ] High Pressure Lines, Installing

12 Bolt

• 23 Nm

TDC in the Crankshaft - 1 -





TDC in the Camshaft - arrow -





Locking Tool (T40135) for the High Pressure Pump Toothed Belt.





Removing the High Pressure Pump Toothed Belt Sprocket





- Remove the high pressure pump toothed belt with the puller (T40064).