Fuel System Schematic Overview

Fuel System Schematic Overview


• Follow the guidelines when working on the fuel system. Refer to => [ Safety Precautions ] Safety Precautions.

• Follow the guidelines for clean working conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions.

• Always follow these rules before and during work.

• If the fuel system components between the fuel tank and high pressure fuel pump were removed or replaced, the fuel system must be filled in order to bleed it. Refer to => [ Fuel System, Filling/Bleeding ] Fuel System, Filling/Bleeding. (Never let the high pressure pump run dry).






1 Fuel Tank

• With the transfer fuel pump.

2 Fuel Filter

• With a pre-warm valve.

3 Auxiliary Fuel Pump (V393) or Fuel Pump 2 (V277)

Removing and installing.

4 Filter

5 Fuel Temperature Sensor (G81)

6 High Pressure Pump

• After replacing, the fuel tank must be filled (never run dry). Refer to => [ Fuel System, Filling/Bleeding ] Fuel System, Filling/Bleeding.

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

7 Fuel Metering Valve (N290)

• Must not be removed.

8 Fuel Pressure Regulator Valve (N276)

• Removing and installing, refer to => [ Fuel Pressure Regulator Valve N276 ] Service and Repair.

9 Fuel Rail (High Pressure Reservoir)

10 Fuel Pressure Sensor (G247)

• Removing and installing, refer to => [ Fuel Pressure Sensor G247 ] Service and Repair.

11 Pressure Retention Valve

• The retention valve always maintains a residual pressure (control quantity) of approximately 10 bar in the fuel return lines.

• The injectors need this control quantity to function correctly.

• The retention valve can be replaced only with the complete fuel return line.

• The engine must run at idle for approximately two minutes after replacing to bleed the fuel system.

• Checking the pressure retention valve. Refer to => [ Fuel Return Line Pressure Retention Valve, Checking ] Testing and Inspection.

12 Fuel Injectors (Piezo Injectors)

• Cylinder 1 fuel injector (N30).

• Cylinder 2 fuel injector (N31).

• Cylinder 3 fuel injector (N32).

• Cylinder 4 fuel injector (N33).

• Removing and installing, refer to => [ Fuel Injectors ] Service and Repair.