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Skoda Workshop Service and Repair Manuals

Checking holding pressure with pressure gauge VAS 6550 > < Check fuel pressure with pressure gauge VAS 6550
Checking holding pressure with pressure gaugeV.A.G 1318
Checking holding pressure with pressure gauge -V.A.G 1318-
   
l  Fuel pressure O.K. and pressure gauge -V.A.G 1318- connected in the engine compartment → Chapter.
  Note
t  Safety precautions when working on the fuel supply system → Chapter.
t  Rules of cleanliness when working on the fuel supply system → Chapter.
–  Switch the ignition on and off so often until the fuel pressure on the pressure gauge does no longer rise.
–  Read off fuel pressure on the pressure gauge.
l  Specified value: 0.4 ... 0.7 MPa (4 ... 7 bar)
–  Observe pressure drop at pressure gauge.
l  The pressure must not drop below 0.3 MPa (3.0 bar) after 10 minutes.
If the pressure still drops:
–  Switch the ignition on and off so often until the fuel pressure on the pressure gauge does no longer rise.
  N20-10428
–  Immediately close the shutoff cock of the pressure measuring device. The lever then points in the position -B-.
If the pressure again drops:
–  Check the low-pressure line to the high pressure pump for tightness.
If no fault is found:
–  Replace high pressure pump → Chapter.
Now the pressure does no longer drop:
–  Check the fuel line to the fuel filter for tightness.
If the fuel line is not found to be faulty:
  N20-10428
–  Check the non-return valve in the fuel delivery unit. For this step connect the pressure measuring device -V.A.G 1318- with the adapter -V.A.G 1318/17A- between the fuel filter and the fuel feed line.
–  Open shut-off cock of the pressure gauge. Lever points in direction of flow.
–  Switch the ignition on and off so often until the fuel pressure on the pressure gauge does no longer rise.
–  Read off fuel pressure on the pressure gauge.
l  Specified value: 0.4 ... 0.7 MPa (4 ... 7 bar)
  S20-0253
–  Immediately close the shut-off cock of the pressure gauge after the pressure has built up.
–  Observe pressure drop at pressure gauge.
l  The pressure must not drop below 0.3 MPa (3.0 bar) after 10 minutes.
If the pressure drops:
–  Non-return valve in the fuel pump faulty, replace fuel delivery unit → Chapter.
If the pressure does not drop:
–  Pressure limiting valve in the fuel filter defective, replace the fuel filter.
  S20-0254

Checking holding pressure with pressure gauge VAS 6550 > < Check fuel pressure with pressure gauge VAS 6550