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Testing injection valves > < Idle testing

Octavia Mk1

Test fuel pressure regulator and holding pressure
Test fuel pressure regulator and holding pressure
Special tools and workshop equipment required
t  Tester e. g. - V.A.G 1318-
t  Adapter e.g. -V.A.G 1318/8-
t  Adapter e.g. -V.A.G 1318/9-
t  Adapter e.g. -V.A.G 1318/17-
Test conditions
l  Fuel pump relay o.k., test → Chapter
l  Fuel pump o.k.
l  Fuel filter o.k.
l  Battery voltage o.k.
  Note
The fuel pressure regulator regulates the fuel pressure in line with the intake manifold pressure at the throttle valve part.
  WARNING
The fuel system is under pressure! Before opening the system lay cleaning cloths around the connection point. Reduce pressure by carefully releasing the connection point.
–  Disconnect the fuel-intake hose (with white marking) from the feed line.
–  Connect the pressure measuring device -V.A.G 1318- with the adapters 1318/8, 1318/9 and 1318/17 to the fuel feed line.
   
–  Open shut-off cock of the pressure measuring device. Lever points in direction of flow.
–  Start engine and run in idle.
–  Measure fuel pressure.
Specified value: approx. 2.5 MPa (0.25 bar) overpressure.
  A24-0107
–  Detach vacuum hose from fuel pressure regulator. The fuel pressure must rise to approx. 3 bar (3 MPa) overpressure.
–  Switch off ignition.
–  Test for leaks and holding pressure while observing the pressure drop on the manometer. An overpressure of at least 1.5 bar (0.15 MPa) must be indicated on the manometer after 10 minutes.
The pressure drops below 1.5 bar (0.15 MPa):
–  Start engine and run in idle.
  A24-0095
–  After the pressure has been built up, switch ignition off. At the same time close the shut-off cock at the pressure measuring device -V.A.G 1318- (lever at right angles to direction of flow).
–  Observe pressure drop at gauge.
If the pressure again drops:
–  Checking the non-return valve on the fuel pump.
If the pressure does not drop:
  A24-0106
–  Open shut-off cock at the pressure measuring device -V.A.G 1318- (lever in direction of flow of fuel).
–  Start engine and run in idle.
–  After the pressure has been built up, switch ignition off. At the same time the return-flow hose (with blue marking) must be pressed together.
If the pressure does not drop:
–  Replace the fuel pressure regulator.
If the pressure again drops:
–  Check line connections, “O” -rings on fuel rail and injectors for leaks.
–  Inspect pressure measuring device for leaks.
  Note
Before removing the pressure gauge appliance, reduce the fuel by opening the shutoff cock and place a cleaning cloth around the connection point.
  A24-0107

Testing injection valves > < Idle testing