Skoda Workshop Service and Repair Manuals

Check fuel flow rate Test conditions l  Supply voltage o.k. l  Remote control -V.A.G 1348/3A- connected. Test sequence –  Unscrew the cap from the filler neck.

–  Detach the fuel feed line -2- and (press the release button) 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.

–  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) overpressure. Now do not change the position of the shut-off cock. –  Drain the 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.

–  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. As the voltage on the pump is approximately 2 V less than the battery voltage, a minimum flow rate of 540 cm3/30 s is obtained. If the minimum flow rate is not reached: –  Check the fuel lines for possible diameter restrictions (kinks) or blocking.

–  Disconnect the hose -1- of the feed line from the fuel filter inlet (filter version with integrated fuel pressure regulator).

–  Disconnect the hose -1- of the feed line from the fuel filter inlet (filter version with separate 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 delivery unit and check whether the pump strainer is not clogged up. If no fault was detected until now: –  Replace fuel delivery unit. The 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.

–  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: maximum 8 A   Note If the fault in the fuel supply system is intermittent then tests can be undertaken during a test drive. The assistance of a 2nd mechanic is required. If the power consumption is exceeded: –  Replace fuel delivery unit.