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Air filter: component overview > < System layout

Leon Mk2

Fuel system: component overview
Fuel system: component overview
  Caution
When installing a new partial engine, the clamping pieces of the injector must be tightened to the specified tightening torque following installation of the high pressure lines → Chapter. The clamping pieces are supplied tightened »hand tight« so that the position of the injectors can be adjusted during the installation of the high pressure lines. Non-observance of these details may lead to damage to the engine.
  WARNING
t  Always read rules for cleanliness and instructions for working on fuel system → Chapter.
t  Always follow these rules for cleanliness and instructions before starting work and while working on the fuel system.
  Caution
The high-pressure fuel pump has very close tolerances and must not be allowed to run without fuel. To prevent this and to enable the engine to start quickly after parts have been renewed, it is important to observe the following:
t  If components of the fuel system between the tank and the high-pressure fuel pump are removed or renewed, the basic setting „Checking fuel system pressurisation pump“ must be performed to bleed the fuel system.
t  If a fuel pump, fuel line or fuel filter are removed or renewed, the basic setting „Checking fuel system pressurisation pump“ must be performed »ONCE« before the engine is started for the first time.
t  If the high-pressure fuel pump is removed or renewed, the basic setting „Checking fuel system pressurisation pump“ must be performed »three times« before the engine is started for the first time.
t  Performing first fuel filling after installing high-pressure pump → Chapter.
  Note
If the first filling is not performed, damage will be caused to the high-pressure fuel pump.
   
1 - 10 Nm
q   Allocation → Fig.
2 - High-pressure line
q   25 Nm
q   Between high-pressure pump and high-pressure reservoir (rail)
3 - Fuel return lines
q   To fuel tank.
q   The fuel return line must not be kinked, damaged or blocked.
q   The fuel return lines must not be dismantled; if necessary they must be renewed complete with pressure retention valve.
q   The pressure retention valve has to maintain a residual pressure (controlled quantity) of approx. 10 bar in the fuel return lines.
q   This residual pressure is required for the control function of the piezo injectors.
q   Checking pressure retention valve → Chapter
q   After replacement, the engine must be run at idling speed for approx. 2 minutes to bleed the fuel system. Then check the fuel return lines for leaks.
q   Consider the different versions → Fig.
4 - 10 Nm
5 - High-pressure lines
q   25 Nm
q   Between high-pressure reservoir (rail) and injectors
q   Do not exchange position
q   Install so that component is not stressed.
  Note
t  Observe cylinder specific markings when reusing high-pressure lines.
t  The high-pressure lines can principally be reuse according to the following test:
t  Check taper seat of respective high-pressure line for deformation and cracks.
t  The line hole must not be deformed, constricted or damaged.
t  Corroded lines should no longer be used.
6 - Fuel pressure regulating valve -N276-
q   80 Nm
q   Cannot be re-installed.
q   Removing and installing → Chapter.
7 - Rail element (high-pressure accumulator)
q   Removing and installing → Chapter.
8 - Fuel supply line
9 - High-pressure fuel pump
q   With fuel metering valve -N290- (do not open).
q   After the replacement, first fuel must be filled (dry running is to be avoided at all costs) → Chapter
q   Removing and installing → Chapter.
10 - 20 Nm
11 - 20 Nm + 90° (1/4 turn) further
12 - Coolant pump toothed belt pulley
13 - 95 Nm
14 - Hub
q   With generator wheel
q   Use counterhold tool -T10051- to loosen and tighten.
q   To remove, use puller -T40064-.
15 - Fuel pressure sender -G247-
q   100 Nm
q   Removing and installing → Chapter.
16 - 22 Nm
17 - Clamping piece
q   If they are to be re-installed, the injectors and clamping pieces must always be re-fitted on the same cylinder.
q   If an injector is replaced, their other clamping piece must also be replaced.
18 - Hexagon flange nut
q   For clamping piece
q   10 Nm
19 - Cover for injector
20 - 5 Nm
21 - Injector (piezo injectors)
q   The following components and seals/O-rings must always be replaced: „copper seal“„O-ring of the injector valve bore“„O-ring on the injector valve return line“
q   The following components and seals/O-rings must always be renewed when an injector is renewed: „clamping piece“, „copper seal“, „O-ring for injector shaft“ and „O-ring for injector return connection“.
q   When re-installing „high-pressure injector pipe“ check taper seats visually for damage, scores and corrosion (always renew if damaged)
q   If they are to be re-installed, the injectors, high-pressure fuel pipes and clamping pieces must always be re-fitted in their original positions (i.e. on the same cylinder).
q   Removing and installing → Chapter.

   
Clamping piece installation position
  N23-10231
Differences, fuel return line
-A-, without grooves: Use a clamp according to the → ETKA (Electronic spare parts catalogue) for connecting the oil leak line.
-A-, without grooves: DO NOT use a clamp for the connection of the oil leak line.
  N23-10273
High-pressure connecting piece between the high-pressure fuel pump and the high-pressure accumulator (Common Rail)
  N23-10274

Air filter: component overview > < System layout