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Replacing O-rings for fuel return-flow line > < System overview

Fabia Mk2

Fuel system in engine compartment - Summary of components
   
Fuel system in engine compartment - Summary of components
  Caution
In order to avoid the high pressure pump to run dry and to achieve a quick engine start after parts are replaced, the following points must be observed:
t  If the fuel system was opened, starting with the fuel tank through to the high pressure pump, the ventilation of the fuel system must be carried out before starting the engine. For this purpose, switch on the ignition and only switch it off once the fuel pump has come to a standstill. Repeat this procedure at least »5 times«.
t  If the high pressure pump is removed or replaced, the initial fuel filling of the high pressure pump must be carried out before the first engine start. For this purpose, connect vehicle diagnosis, measurement and information system -VAS 505x- and carry out the targeted function „filling/bleeding the high pressure pump and the fuel system“. During this function, the fuel pump is actuated for 180 seconds.
t  If the high pressure system was opened, it must be checked for tightness → Chapter.
Observe the instructions for the fuel hose in the engine compartment → Chapter.
1 - O-ring
q   replace if damaged
q   removing and installing → Chapter
2 - Fuel return-flow lines
q   to high pressure pump
q   they must not be kinked, damaged or blocked
q   do not disassemble
q   Test vacuum → Chapter
q   after an exchange, the engine must run at idling speed for approx. 2 minutes in order to vent the fuel system; afterwards check the fuel return-flow lines for tightness
3 - High pressure lines, 15 Nm + torque a further 60° (1/6 turn)
q   between fuel distributor and injection units
q   do not interchange
  Note
t  Pay attention to the cylinder specific marking when re-using the high pressure lines.
t  The high pressure lines can be re-used if:
l  The sealing cone of the relevant high pressure line is not deformed or cracked.
l  The line boring is not deformed, constricted or damaged.
t  Corroded lines must no longer be installed.
q   install free of stress
4 - Connecting hose
q   replace → Chapter
5 - Spring strap clamp
6 - Fuel pressure regulating valve -N276-, 80 Nm
q   replace after each removal
q   check → Chapter
q   removing and installing → Chapter
7 - Fuel distributor
q   removing and installing → Chapter
8 - 9 Nm
9 - 22 Nm
10 - Fuel pressure sender -G247-, 100 Nm
q   removing and installing → Chapter
11 - Fuel return-flow line
q   to fuel feed
12 - High pressure line, 15 Nm + torque a further 60° (1/6 turn)
q   between the high pressure pump and the fuel distributor
q   install free of stress
  Note
The high pressure line can be re-used, if:
l  The sealing cone of the high pressure line is not deformed or cracked.
l  The line boring is not deformed, constricted or damaged.
  Note
A corroded high pressure line must not be reinstalled.
13 - High pressure pump
q   with fuel dosage valve -N290-
q   Test vacuum (Venturi pipe) → Chapter
q   removing and installing → Chapter
q   after the installation, an initial fuel filling must be carried out (absolutely avoid it to run dry)
14 - 20 Nm + torque a further 180° (1/2 turn)
q   replace
15 - 20 Nm + torque a further 45° (1/8 turn)
q   replace
16 - 20 Nm
17 - Toothed belt gear
q   on the high pressure pump
18 - 95 Nm
q   for loosening and tightening the hub (Pos. 19) counterhold with counterholder -T10051-
19 - Hub
q   to remove use extractor -T40064-
20 - Copper disc
q   replace
21 - Clamping claw
22 - 10 Nm + torque a further 180° (1/2 turn)
q   replace
23 - Injection unit (solenoid injector)
q   removing and installing → Chapter
q   List of parts and gaskets or O-rings which must be replaced each time when removing and installing: „copper disc“, „O-ring of bore for injection unit“, „O-ring for fuel return-flow line“.
q   List of parts and gaskets or O-rings which must be replaced each time when replacing the injection unit: „clamping claw“, „copper disc“, „O-ring of bore for injection unit“, „O-ring for fuel return-flow line“.
q   before re-using the „high pressure line“ carry out a visual inspection of the sealing cones for damage, e.g. cross chamfers and corrosion, always replace if damaged
q   Injection units, high pressure lines and clamping claws, which are re-installed, may only be mounted again at the same cylinder.

   

Replacing O-rings for fuel return-flow line > < System overview