volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

ABOUT US
Assembly overview - installation position of clamp > < System layout: vehicles with 6.0 bar low-pressure fuel system

Polo Mk5

Assembly overview - fuel system
Assembly overview - fuel system
Safety precautions → Chapter.
Rules for cleanliness → Chapter.
  Caution
To prevent the high-pressure fuel pump from running while it is empty and to ensure that the engine starts quickly after parts have been renewed, it is important to observe the following:
t  If fuel system components between fuel tank and fuel high-pressure pump are removed or replaced.
t  Basic setting „Checking fuel pre-supply pump“ must be carried out to bleed fuel system.
t  If a fuel pump, fuel pipe (between fuel tank and fuel high-pressure pump) or fuel filter is removed or renewed.
t  Basic setting „Testing fuel pre-supply pump“ must be carried out »once« before first starting engine.
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.
   
1 - Fuel return lines (from injectors)
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.
q   Only renew O-ring if necessary
q   The pressure retention valve maintains a residual pressure in the return lines.
q   This residual pressure is required for the control function of the injectors.
q   Check pressure retention valve → Chapter.
2 - Fuel pressure regulating valve -N276-
q   Cannot be re-installed.
q   Removing and installing → Chapter.
q   80 Nm
3 - Fuel return lines (from injectors)
4 - Bolt
q   10 Nm
5 - High-pressure fuel pump
q   Removing and installing → Chapter.
q   With fuel metering valve -N290- (do not open).
q   After renewing, a first fuel filling must be performed (never allow the pump to run while it is still empty) → Chapter.
6 - Bolt
q   20 Nm + turn 180° further.
7 - Hub
q   With sender ring
q   Use counterhold tool -T10051- to loosen and tighten.
q   To remove, use puller -T40064-.
8 - Nut
q   95 Nm
9 - Toothed belt pulley on high-pressure pump
q   Bolts: 20 Nm + turn 90° further
10 - Bolt
q   20 Nm + turn 45° further
11 - Bolt
q   10 Nm
12 - High-pressure line
q   28 Nm
q   Between high-pressure pump and rail element (high-pressure accumulator)
q   Install so that component is not under tension.
  Note
t  The high-pressure line may be re-used after the following checks:
t  Check taper seat of 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.
13 - Fuel pressure sender -G247-
q   Removing and installing → Chapter.
q   100 Nm
14 - Rail element (high-pressure accumulator)
q   Removing and installing.
15 - Bolt
q   22 Nm
16 - High-pressure lines
q   28 Nm
q   Between rail element (high-pressure accumulator) and injectors
q   Do not interchange.
q   Install so that component is not under tension.
  Note
t  Observe cylinder specific markings when reusing high-pressure lines.
t  The high-pressure lines may be re-used after the following checks:
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.
17 - Gasket
q   Renew cylinder head cover if damaged.
18 - Gasket
19 - Injectors
q   Removing and installing → Chapter.
q   The following components and seals/O-rings must be renewed each time on removal/installation: „copper seal“, „O-ring for injector bore“, „bolt for clamping piece“ and „retaining clip for return connection“.
q   The following components and seals/O-rings must be renewed when an injector is renewed: „clamping piece“, „copper seal“, „bolt for clamping piece“
q   Before re-using „high-pressure line“, perform visual check of taper seats for damage such as transverse scores or corrosion; always renew if damaged.
q   If they are to be re-installed, injectors, high-pressure fuel lines and clamping pieces must always be re-fitted in their original positions (i.e. on the same cylinder).
20 - Bolt for clamp
q   Renew.
Tighten securing bolts to a maximum of 1 to 2 Nm at first.
After the high-pressure lines have been fitted. Final tightening torque: 8 Nm + turn 180° further.
21 - O-ring (leakage lines, fuel return lines)
q   Following component must be renewed every time the fuel return lines are removed and installed: „fuel return line retaining clip“
q   Only renew O-ring if necessary

O-ring for fuel return lines. Removing.
Proceed with extreme caution. Avoid damage to fuel return line.
–  Lever old O-ring very carefully off fuel return line.
Do not work with a sharp-edged tool.
O-ring for fuel return lines. Installing.
  Note
Prevent O-rings from rolling when sliding them on. The O-rings must not be twisted in their seats in fuel return line.
Proceed with extreme caution. Avoid damage to the O-ring and fuel return line.
–  Clean seating surfaces for O-rings on fuel return line very carefully.
   
–  Carefully push O-ring -1- on its seat -2-.
Different types of fuel return lines are fitted.
  N23-10429
1 - Fuel return line for 0.5 bar low-pressure fuel system → Item
q   Flexible.
q   With pressure retention valve
2 - Fuel return line for 6.0 bar low-pressure fuel system → Item
q   Flexible.
q   With pressure retention valve
3 - Fuel return lines for 0.5 bar low-pressure fuel system
q   Rigid.
4 - Fuel return lines for 6.0 bar low-pressure fuel system
q   Rigid.

Differences: high-pressure pumps with fuel pressure regulating valve -N276-
   
1 - High-pressure pump for 0.5 bar low-pressure fuel system
q   With booster pump fitted to high-pressure pump.
2 - High-pressure pump for 6.0 bar low-pressure fuel system
q   Without booster pump.
q   The requisite 6.0 bar pressure in the low-pressure fuel system is generated by the fuel delivery unit.
3 - Fuel pressure regulating valve -N276- 0.5 bar low-pressure fuel system
  Note
t  Fuel pressure regulating valve -N276- of 0.5 bar low-pressure fuel system looks similar to that of 6.0 bar low-pressure fuel system.
t  Observe the index as per → ETKA (electronic parts catalogue).
q   -High-pressure accumulator- with fuel pressure sender -G247-
4 - Fuel pressure regulating valve -N276- 6.0 bar low-pressure fuel system
  Note
t  Fuel pressure regulating valve -N276- of 6.0 bar low-pressure fuel system looks similar to that of 0.5 bar low-pressure fuel system.
t  Observe the index as per → ETKA (electronic parts catalogue).
q   -High-pressure accumulator- with fuel pressure sender -G247-

   

Assembly overview - installation position of clamp > < System layout: vehicles with 6.0 bar low-pressure fuel system