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Inspecting the non-return valve of the fuel delivery unit and holding pressure > < Check fuel flow rate

Fabia Mk1

Checking fuel operating pressure
Checking fuel operating pressure
Special tools and workshop equipment required
t  Remote control, e.g. -V.A.G 1348/3A- with adapter cable -V.A.G 1348/3-2-
t  Pressure gauge, e.g. -V.A.G 1318-
t  Adapter, e.g. -V.A.G 1318/1-
t  Adapter, e.g. -V.A.G 1318/11-
t  Adapter, e.g. -V.A.G 1318/17-
t  Vehicle system tester -V.A.G 1552- with cable -V.A.G 1551/3, 3A, 3B oder 3C-
   
–  Detach the fuel feed line -2- and (press the release button) and catch the fuel which flows out with a cleaning cloth.
  S10-0389
–  Connect the pressure gauge -V.A.G 1318- with adapter -V.A.G 1318/11- and -V.A.G 1318/17- to the fuel feed line, the shut-off cock on the measuring device must be in position -A-.
–  Start engine.
  Note
Fuel filters with different fuel pressure regulators, 3 and 4 bar, were installed, when checking the fuel pressure pay attention to which one is installed in the vehicle → Electronic Catalogue of Original Parts
For vehicles with 3 bar fuel pressure regulators
Specified value 0,3 MPa (3 bar).
If the specified value is higher than 0,3 MPa (3 bar):
–  Check fuel return-flow line between the fuel filter and the fuel pump for continuity or replace fuel pressure regulator.
If the specified value is lower than 0.3 MPa (3 bar):
–  Check lines and fuel rail for leaktightness.
For vehicles with 4 bar fuel pressure regulators
Specified value 0.4 MPa (4 bar).
If the specified value is higher than 0.4 MPa (4 bar):
–  Check fuel return-flow line between the fuel filter and the fuel pump for continuity or replace fuel pressure regulator.
If the specified value is lower than 0.3 MPa (3 bar):
–  Check lines and fuel rail for leaktightness.
  S20-0106
–  Connect the pressure gauge -V.A.G 1318- with adapter -V.A.G 1318/11- and -V.A.G 1318/17- to the black feed line from the pump to the fuel filter (old version filter shown with integrated fuel pressure regulator). For the new version of the filter with disassembled fuel pressure regulator the black feed line is connected to the fuel filter outer connection.
For vehicles with 3 bar fuel pressure regulators
–  Open shut-off cock on the measuring device -position A-.
–  Start engine.
Specified value 0,3 MPa (3 bar) and higher.
If the specified value is not reached:
–  Close shut-off cock -position B-.
Actuate the fuel delivery unit with the remote control -V.A.G 1348/3A-.
–  Connect remote control -V.A.G 1348/3A- → Chapter.
–  Activate remote control until a pressure of at least 0,27 MPa (2,7 bar) is built up.
The fuel delivery unit can also be actuated using the actuator diagnosis:
–  Connect vehicle system tester -V.A.G 1552-, switch on ignition and enter the address word 01 - Engine electronics → Vehicle diagnostic, testing and information system VAS 5051.
–  Select function 03 „Final control diagnosis“, and confirm the entry with the key Q.
  S20-0105
–  Using the key → select the final control diagnosis for fuel pump relay.
–  The fuel pump will run for approx. 20 seconds or until the key → is activated.
–  End final control diagnosis for fuel pump relay after reaching min. 0,3 MPa (3 bar).
–  Proceed with the final control diagnosis up to the end.
–  Select function 06 „End output“ and switch ignition off.
If the nominal value of at least 0,3 bar (3 MPa) is reached:
–  Replace the fuel pressure regulator.
If the nominal value of min. 0,3 MPa (3 bar) is not reached:
–  Replace fuel delivery unit.
For vehicles with 4 bar fuel pressure regulators
–  Open shut-off cock on the measuring device -position A-.
–  Start engine.
Specified value 0.4 MPa (4 bar) and higher.
If the specified value is not reached:
–  Close shut-off cock -position B-.
Actuate the fuel delivery unit with the remote control -V.A.G 1348/3A-.
–  Connect remote control -V.A.G 1348/3A- → Chapter.
–  Activate remote control until a pressure of at least 0.37 MPa (3.7 bar) is built up.
The fuel delivery unit can also be actuated using the actuator diagnosis:
–  Connect vehicle system tester -V.A.G 1552-, switch on ignition and enter the address word 01 - Engine electronics → Vehicle diagnostic, testing and information system VAS 5051.
–  Select function 03 „Final control diagnosis“, and confirm the entry with the key Q.
  
Actuator diagnosis                   → 
Fuel pump relay-J17
–  Using the key → select the final control diagnosis for fuel pump relay.
–  The fuel pump will run for approx. 20 seconds or until the key → is activated.
–  End final control diagnosis for fuel pump relay after reaching min. 0.4 MPa (4 bar).
–  Proceed with the final control diagnosis up to the end.
–  Select function 06 „End output“ and switch ignition off.
If the nominal value of at least 0.4 bar (4 MPa) is reached:
–  Replace the fuel pressure regulator.
If the nominal value of min. 0.4 MPa (4 bar) is not reached:
–  Replace fuel delivery unit.
  WARNING
Maximum pressure of the fuel delivery unit is 0.7 MPa (7 bar). If this pressure is reached - risk of damage to the fuel delivery unit.
  
Actuator diagnosis                   → 
Fuel pump relay-J17

Inspecting the non-return valve of the fuel delivery unit and holding pressure > < Check fuel flow rate