Skoda Workshop Service and Repair Manuals

Check fuel flow rate   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 off the ignition and all electrical components and take out the ignition key. –  Remove rear seat bench with brackets → Body Work → Rep. gr.72. –  Remove floor covering under the rear seat bench.

–  Disconnect plug -3- from fuel pump control unit -J538--1-. Vehicles with auxiliary heating. –  Unplug the 2-pin plug of the dosing pump -V54-. Continued for all vehicles –  Unclip cover -4-.

–  Unplug connector -1-.

–  Connect the remote control -V.A.G 1348/3A - with adapter cables at contact -1(+)- of fuel pump and at contact -1(+)- of 10-pin plug. –  Connect the contact -6(-)- of the 10-pin plug with the contact -5(-)- of the fuel pump using an adapter cable from the adapter cable set -V.A.G 1594 C-. –  Take cap off fuel filler neck.

–  Remove the feed line -2- (press in the securing ring to the top) and catch the fuel which flows out with a cleaning cloth.

–  Connect the pressure gauge - V.A.G 1318- with the double connection piece -V.A.G 1318/23 - and the adapter set -V.A.G 1318/17- to the fuel feed line. –  Fit the hose adapter -V.A.G 1318/16 - onto the adapter -V.A.G 1318/11- of the pressure measuring device and hold it in a measuring vessel. –  Close the shut-off cock of the pressure measuring device. The lever then points in the position -B-.   WARNING Danger of liquid spraying out when opening the shut-off valve. Wear safety goggles and safety clothing, in order to avoid injuries and skin contact with fuel. Hold the container in front of the free connection to the pressure gauge. –  Open shut-off cock of the pressure gauge. The lever then 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 0.4 MPa (4 bar) overpressure. Now do not make any further changes to the position of the shut-off cock. –  Empty measuring glass. –  The fuel flow rate of the fuel pump is dependent on the battery voltage. Therefore attach the multimeter -V.A.G 1715 - with adapter cables from the measuring tool set - V.A.G 1594 C- 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 1 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 fuel pump is approx. 2V less than the battery voltage, a minimum flow rate of approx. 580 cm3/30 s is obtained. If the minimum delivery volume is not reached: –  Check the fuel lines for possible restrictions (kinks) or blocking. If no fault is found:

–  Disconnect the feed hose -1- from the fuel filter inlet. –  Connect pressure gauge -V.A.G 1318- with the adapter set -V.A.G 1318/17- to the hose. –  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 fuel delivery unit and inspect the filter strainer for soiling. If you have still not found any fault up to this stage: –  Replace fuel delivery unit → Chapter. If the required delivery volume has been achieved, but a fault is still suspected in the fuel supply system (e.g. intermittent breakdown of the fuel supply). –  Check power consumption of the fuel delivery unit → Chapter.