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.

–  Pull off the fuel feed line -arrow- and gather residual fuel in a cloth → Chapter.   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 this, slowly close the shut-off cock until the pressure gauge displays 3 bar (0.3 MPa) pressure. Now do not change the position of the shut-off cock. –  Drain the measuring vessel. The fuel flow rate of the fuel delivery unit 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 at the fuel pump when engine is not running and pump is operating (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) → Chapter.

–  Disconnect the hose -1- of the feed line from the fuel filter inlet (filter version with separate fuel pressure regulator) → Chapter. –  Connect pressure gauge appliance -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 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 delivery unit as follows: –  Connect all released fuel lines.

–  Connect multimeter with current probe on the line from contact -1- of the connector of the fuel delivery unit. –  Start engine and run in idle. –  Measure power consumption of the fuel delivery unit. 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 → Chapter.