skoda Workshop Repair Guides

Skoda Workshop Service and Repair Manuals

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Inspecting the operating and holding pressure of the fuel, checking the non-return valve of the fuel pump > < Inspecting proper operation and power supply

Fabia Mk2

Check fuel flow rate
Check fuel flow rate
Test conditions
l  Supply voltage is o.k.
l  Remote control -V.A.G 1348/3A - connected.
Test sequence
–  Unscrew the cap from the filler neck.
   
–  Pull out the fuel feed line -2- and catch the fuel which flows out with a cleaning cloth.
  WARNING
The fuel feed line is pressurized! Place a clean cleaning cloth around the connection point before detaching hose connections. Reduce pressure by carefully releasing the connection point.
  S10-0389
–  Connect pressure gauge -V.A.G 1318- with adapter -V.A.G 1318/23 - and -V.A.G 1318/17 - to the fuel feed line.
–  Connect hose -V.A.G 1318/1- with adapter -V.A.G 1318/11- of the pressure gauge and hold in the measuring vessel.
–  Open shut-off cock of the pressure gauge. The lever points in the direction of flow -A-.
–  Activate remote control -V.A.G 1348/3A-. While doing so, slowly close the shut-off cock until the pressure gauge displays 0.3 MPa (3 bar) pressure. Now do not change the position of the shut-off cock.
–  Empty measuring vessel.
–  The fuel flow rate of the fuel pump is dependent on the battery voltage. Therefore connect the multimeter with the adapter cable to the vehicle battery.
–  Activate remote control for 30 seconds while measuring the battery voltage.
  N20-0132
–  Compare the fuel rate with the specified value.
*) Minimum flow rate in cm3/30 s
**) Voltage on the fuel pump when the engine is stopped and the pump is running (approx. 2 volts less than battery voltage).
Read out examples:
During the test a voltage of 12.5 V was measured on the battery. The voltage at the fuel pump is about 2 volts less than the battery voltage. Thereby a minimum flow rate of 540 cm3/30 s is shown in the diagram.
If the minimum flow rate is not reached:
–  Check the fuel lines for possible restrictions (kinks) or blocking.
  S20-0204
–  Disconnect the hose -1- of the feed line from the fuel filter inlet (filter version with integrated fuel pressure regulator).
–  Connect pressure gauge -V.A.G 1318- with adapter -V.A.G 1318/17 - to the hose -1-.
–  Repeat fuel flow rate test.
If the minimum flow rate is now reached:
–  Replace fuel filter.
If the minimum flow rate is again not reached:
–  Remove the fuel pump and check whether the pump strainer is not clogged up.
If no fault was detected until now:
–  Replace fuel delivery unit.
The fuel flow rate was reached but a fault in the fuel supply system is suspected (e.g. temporary failure of the fuel supply system).
–  Check the power consumption of the fuel pump as follows:
–  Connect all released fuel lines.
  S20-0319
–  Connect the multimeter with the current probe on the line from contact -1- of the connector of the fuel pump.
–  Start engine and run in idle.
–  Measure voltage consumption of the fuel pump.
Specified value: max. 8 A
  Note
If the failure in the fuel supply is occasional the test may be performed during a test drive. The assistance of a 2nd mechanic is required.
If the power consumption is exceeded:
–  Replace fuel delivery unit.
  S20-0298

Inspecting the operating and holding pressure of the fuel, checking the non-return valve of the fuel pump > < Inspecting proper operation and power supply