Fuel System Component Overview
Fuel System Component Overview
• Follow the guidelines for a clean working environment when working on the fuel system => [ Clean Working Conditions and Fuel System Work Instructions ] Clean Working Conditions and Fuel System Work Instructions.
• Always follow these rules before and during work.
1 Fuel Return Line
• To the fuel tank.
• The fuel return line must not be bent, damaged or plugged.
2 Fuel Supply Line
• Coming from the fuel filter.
3 Fuel Return Line Banjo Bolt
4 Fuel Temperature Sensor (G81)
5 Bolt
6 Bracket
7 Fuel Pressure Regulator Valve (N276)
• Installed on the cylinder bank 1 fuel rail.
• Cannot be reused again
• Removing and installing, refer to => [ Fuel Pressure Regulator Valve N276 ] Service and Repair.
8 Bolt
9 Bracket
10 High Pressure Fuel Line
• 28 Nm
• Between the high pressure pump and the fuel rail.
11 High Pressure Fuel Line
• 28 Nm
• Between the fuel rail on cylinder bank 1 and the fuel rail on cylinder bank 2.
• Before reusing the "high pressure fuel line", check the sealing cones for damage such as scratches or corrosion. Replace if damaged.
• If the high pressure fuel line is not OK, always replace the high pressure line.
12 High Pressure Fuel Pump
• With the fuel metering valve.
• Fill the fuel tank after replacing the high pressure fuel pump (never run dry). Refer to => [ Fuel System, Bleeding and First Time Filling ] Fuel System, Bleeding and First Time Filling.
• High pressure pump overview. Refer to => [ High Pressure Pump Overview ] High Pressure Pump Overview.
• Removing and installing, refer to => [ High Pressure Fuel Pump ] High Pressure Fuel Pump.
13 Fuel Return Lines (Leak Lines)
• Do not disassemble the fuel return lines. Replace them completely with the pressure retention valve.
• Run the engine at idle for approximately two minutes after replacing to bleed the fuel system and then check the fuel return lines for leaks.
14 Bolt
• 5.5 Nm
• Sealing cap to cylinder head cover.
15 Sealing Cap
16 Tensioning Plate
• Injectors and tensioning plates that have been removed and are being reinstalled may only be reinstalled to the same cylinder as removed.
• If the fuel injector is being replaced, then the tensioning plate must also be replaced.
17 Nut
• 10 Nm
• For the tensioning plate.
18 Bolt
• 22 Nm
• For the cylinder bank 2 fuel rail.
19 Fuel Pressure Sensor (G247)
• 30 Nm
• Installed in the fuel rail for cylinder bank 2.
• Removing and installing, refer to => [ Fuel Pressure Sensor G247 ] Service and Repair.
20 Seal
• Always replace.
21 High Pressure Fuel Line
• 28 Nm
• For cylinder bank 2.
22 Fuel Rail (High Pressure Reservoir)
• For cylinder bank 2.
23 Seals
• Always replace.
24 Nut
• 10 Nm
• For the tensioning plate.
25 Fuel (Piezo) Injector
• Replace the following components, seals or O-rings with each removal and installation: "Copper washer", "injector shaft O-ring" and "injector return O-ring"
• The following components, seals and/or O-rings must be replaced whenever an injector is replaced: "Tensioning plate", "copper washer", "fuel injector shaft O-ring" and "fuel injector return O-ring"
• Before reusing the "high pressure line", check the sealing cones for damage such as scratches or corrosion. Replace if damaged.
• If any injector, high pressure line and tensioning plate, which were removed, are being reinstalled, then they must be reinstalled to the same cylinder.
• Removing and installing, refer to => [ Fuel (Piezo) Injectors ] Service and Repair.
26 Bolt
• 5.5 Nm
• Sealing cap to cylinder head cover.
27 Sealing Cap
28 Seal
• Always replace.
29 High Pressure Fuel Line
• 28 Nm
• For cylinder bank 1.
30 Bolt
• 22 Nm
• For the cylinder bank 1 fuel rail.
31 Fuel Return Line (Leak Lines)
• Do not disassemble the fuel return line. Replace them completely with the pressure retention valve.
• Run the engine at idle for approximately two minutes after replacing to bleed the fuel system and then check the fuel return lines for leaks.
32 Pressure Retention Valve
• In the fuel return lines for cylinder banks 1 and 2.
• The function of the pressure retention valve in the fuel return line is to constantly guarantee some residual pressure (control quantity).
• The fuel injectors need this control quantity to function correctly.
• Always replace the entire valve at the same time the fuel return lines are replaced.
• The engine must run at idle for approximately two minutes after replacing to bleed the fuel system.
• Checking, refer to => [ Fuel Return Line Pressure Retention Valve, Checking ] Testing and Inspection.