SEAT Workshop Service and Repair Manuals

Fuel delivery quantity: check l  Speedometer must be okay. l  Fuel pressure controller and retaining pressure okay; check → Chapter l  Fuel filter is OK –  Remove filler cap from fuel tank filler neck. –  Remove the rear right seat → Rep. gr.72.

–  Remove cover from fuel delivery unit.

–  First check if the connector -arrow- has been inserted correctly; pull on the connector without pressing the locking mechanism. Malfunctions may arise when the connector has not been inserted correctly. –  Extract the connector -arrow- from the fuel delivery unit. –  Check the contact on the plug connector and the fuel supply unit for damage.

–  Connect the adapter for the DSO measuring/oscilloscope module (5 contacts) -VAS 5565-to the connector in the fuel supply unit. –  Connect the remote control -V.A.G 1348/3A- to the measurement adapter / DSO (5 pin) -VAS 5565- and to battery positive (+).   Note The fuel delivery rate of the fuel pump is measured at a pressure of 4 bar. Therefore, check fuel pressure before measuring delivery rate → Chapter.   WARNING Fuel supply line is pressurised. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then eliminate the pressure by carefully separating the pipe.

–  Pull return line -1- off fuel pressure regulator.   Note Press in safety ring to release fuel lines. –  Connect the Adapter -VAS 6550/1- to the fuel pressure regulator and place the adaptor end in a measuring container. –  Operate the remote control -V.A.G 1348/3A- for 5 seconds to fill the fuel filter. –  Empty the measuring container.

–  The quantity of fuel delivered by the fuel pump is dependent upon voltage. For this purpose, connect multimetre -V.A.G 1715- to outputs -1 and 5- on adapter for measuring equipment / DSO (5 pin) -VAS 5565-. –  Operate remote control for 30 seconds and measure battery voltage.

–  Compare the fuel flow measured with the specification. *) Minimum delivery rate cm3/30 s **) Voltage on the fuel pump when the engine is stationary and with running pump (approx. 2 volt under battery voltage). Readout example: During the test, the battery voltage is measured at 12.5 volts. As the voltage at the pump is approx. 2 V less than the battery voltage, this will equate to a minimum delivery of 580 cm3/30 s. If the minimum delivery rate is not attained: –  Check the fuel supply pipes to the filter for possible restrictions (kinks) or blockages. If the fuel line is not damaged: –  Remove the filler cap on the fuel filler neck and repeat the inspection. If the specified delivery quantity is not reached, check the purging of the fuel tank. If reading again does not match specification: –  Check the fuel filter. Proceed as follows:   WARNING Fuel supply line is pressurised. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then eliminate the pressure by carefully separating the pipe.

–  Remove the supply hose -arrow- from the fuel filter inlet.

–  Connect fuel supply pipe to pressure tester -VAS 6550-, using adapter -VAS 6550/1-. Guide the adapter -VAS 6550/2- into a measuring beaker. –  Make sure that the drain cock is closed and that the flow valves are open. –  Operate the remote control -V.A.G 1348/3A-. Slowly close the shut-off valve -A- until a pressure of 4 bar is indicated on the pressure gauge. From here on, do not change position of shut-off tap. –  Empty the measuring container. –  Activate the remote control for 30 seconds. Compare the quantity of the fuel supplied with the first value measured. If the minimum delivery rate is now attained: –  Replace the fuel filter. If the minimum delivery rate is again not attained: –  Remove the fuel delivery unit and check the strainer filter for soiling. Only when up to now no fault has been detected: –  Renew fuel delivery unit → Chapter. –  Reconnect all disconnected fuel pipes. –  Bleeding the fuel system → Chapter. If delivery quantity has been attained, but nevertheless you suspect a fuel supply system fault (e.g. intermittent failure of fuel supply system): –  Checking current consumption of fuel pump → Chapter.