Fuel Rail and Injectors Overview
Fuel Rail and Injectors Overview
Special tools, testers and auxiliary items required
• Hose Clip Pliers (VAS 6362)
• Hoses are secured with spring type clamps.
• Hose clip pliers (VAS 6362) or (VAS 6340) are recommended for installing spring clamps.
• Follow the safety precautions when working on the diesel direct injection system. Refer to => [ Safety Precautions ] Diesel Fuel Injection.
• Observe the rules for cleanliness. Refer to => [ Clean Working Conditions ] Diesel Fuel Injection.
Always follow these instructions before and during work.
Follow the points below to avoid running the high pressure fuel pump dry and to start the engine quickly after replacing the components:
• The fuel system parts/components between the fuel tank and the high pressure fuel pump being removed or replaced.
• It is necessary to perform the basic setting "Checking Transfer Fuel Pump" in order to bleed the fuel system.
• A fuel pump, fuel line (between the fuel tank and the high pressure fuel pump or the fuel filter was removed or replaced.
• It is necessary to perform the basic setting "Checking Transfer Fuel Pump" 1 time before starting the engine for the first time.
• If the high pressure fuel pump was removed or replaced, perform the basic setting "Checking Transfer Fuel Pump" 3 times before starting the engine for the first time.
• Fill the fuel tank after installing the high pressure pump. Refer to => [ Fuel System, Filling and Bleeding ] Fuel System, Filling and Bleeding.
1 Protective Strip
• For the fuel rail - item 7 - and high pressure lines - item 5 -.
2 Fuel Return Line
• With the pressure retention valve - item 8 - in the => [ System Overview ] Removal and Replacement.
• The fuel return lines must be routed correctly. They may be replaced only with the pressure retention valve.
• Run the engine at idle for approximately two minutes after replacing, in order to bleed the fuel system and then check the fuel return lines for leaks.
• Checking the pressure retention valve in the fuel return line. Refer to => [ Pressure Retention Valve in Fuel Return Line, Checking ] Testing and Inspection.
3 Bolt/Nut
• 8 Nm
4 Fuel Return Line
• Blue or with a blue mark.
• Ensure the line is seated securely.
• From the fuel filter.
5 High Pressure Lines
• 28 Nm
• Between the fuel rail - item 7 - and the fuel injector - item 20 -
The high pressure lines can be reused only after the following checks:
• Check the sealing cone on each high pressure line for deformation and cracks.
• The bores for the lines must not be deformed, narrowed or damaged.
• Do not use corroded lines again.
• Do not interchange.
• When installing, the fuel injectors - item 20 - and high pressure lines may only be installed to the same cylinder as before.
• Do not change the angles of the high pressure lines.
• Install without tension.
6 Fuel Pressure Regulator Valve (N276)
• 80 Nm
• Removing and installing, refer to => [ Fuel Pressure Regulator Valve N276 ] Service and Repair.
7 Fuel Rail
8 Fuel Temperature Sensor (G81)
9 Fuel Supply Line
• Ensure the line is seated securely.
• Between the fuel temperature sensor - item 8 - and the high pressure fuel pump - item 10 -
10 High Pressure Fuel Pump
• With the fuel metering valve - item 1 - in => [ System Overview ] Removal and Replacement.
• Removing and installing, refer to => [ High Pressure Fuel Pump ] High Pressure Fuel Pump.
• The fuel system MUST always be filled after replacing (never run dry). Refer to => [ Fuel System, Filling and Bleeding ] Fuel System, Filling and Bleeding.
11 Bolt
• 20 Nm
12 Bracket
• For the fuel temperature sensor - item 8 -.
13 Fuel Supply Line
• White or with a white mark.
• Ensure the line is seated securely.
• From the auxiliary fuel pump.
• Auxiliary fuel pump removing and installing. Refer to => [ Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump) ] Auxiliary Fuel Pump V393 (In-Line Electric Fuel Pump).
14 Fuel Pressure Sensor (G247)
• 100 Nm
• Removing and installing, refer to => [ Fuel Pressure Sensor G247 ] Service and Repair.
15 Bolt
• 22 Nm
16 Tensioning Plate
• Always replace.
• Note the installed position, refer to => [ Tensioning Plate Installed Position ].
17 Nut
• 10 Nm
18 Sealing Cap
19 Bolt
• 5 Nm
20 Fuel Injector
• The following components must be replaced at every removal and installation: "tensioning bracket", "copper washer", "fuel injector shaft seal" and "fuel injector return seal".
• The following components must be replaced when replacing the fuel injector: "tensioning bracket", "fuel injector line", "copper washer" "fuel injector shaft seal" "fuel injector return seal"
• When installing, the fuel injectors and high pressure lines - item 5 - may only be installed on the same cylinder as before.
• Removing and installing, refer to => [ Fuel Injector ] Fuel Injector.
21 High Pressure Line
• 28 Nm
• Between the high pressure fuel pump - item 10 - and fuel rail - item 7 -.
The high pressure line can be reused only after the following checks:
• Check the sealing cone on the high pressure line for deformation and cracks.
• The bores for the line must not be deformed, narrowed or damaged.
• Do not use a corroded line again.
• Do not change the angles of the high pressure line.
• Install without tension.
Tensioning Plate Installed Position
Fuel Return Line Differences
- A -, no ribbing: for connecting the overflow fuel line, use a clamp. Refer to the Parts Catalog.
- B -, with ribbing: for connecting the overflow fuel line, do NOT use a clamp