SEAT Workshop Service and Repair Manuals

Checking fuel delivery rate (engine code BYT, BZB) –  Remove the rear seat bench → bodywork - interior fitting work; Rep. gr.72.

–  Remove the cover -1- of the fuel delivery unit together with the fuel pump control unit -J538--2-.

–  First check that the connector -arrow- is fitted securely by pulling the connector without pressing the catch. The connector can cause a fault if it has not been fitted correctly. –  Unplug connector -arrow-. –  Check the contacts on the connector and on the fuel delivery 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 V.A.G. 1348 remote control -V.A.G 1348/3A-to the DSO (5 contacts) adapter for measuring/oscilloscope -VAS 5565-and to positive (+) on the battery.   Note The following operation is to make the fuel pump run when the engine is stopped. –  Remove filler cap from fuel tank filler neck.   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 off supply pipe/hose -arrow- and clean spills with a cloth.   Note Press in safety ring to release fuel lines.

–  Connect fuel supply pipe to pressure tester -VAS 6550-, using adapter -VAS 6550/2-. Guide the adapter -VAS 6550/1- into a measuring beaker. –  Make sure that drain tap is closed and cut-off taps are open.   WARNING Fuel may splash when opening the shut-off valve. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Place a container under the free coupling of the pressure gauge. –  Operate the remote control -V.A.G 1348/3A-. Slowly open the shut-off cock -arrow- until pressure gauge indicates 4 bar. From here on, do not change position of shut-off tap. –  Empty the fuel tank

–  The quantity of fuel flow quantity delivered by the fuel pump is dependent upon battery voltage. For this purpose, connect multimeter -V.A.G 1715- to outputs -1 and 5- on adapter for measuring equipment / oscilloscope DSO (5 pin) -VAS 5565-. –  Operate remote control for 60 seconds and measure battery voltage.

–  Compare quantity of fuel delivered with specification. *) Minimum delivery rate cm³/60 seconds **) 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 10.5 volts. As the voltage at the pump is approx. 2 V less than the battery voltage, this will equate to a minimum delivery of 1,200 cm³/60 s. If specification is not obtained: –  Check to ensure that there are no crushing points (kinks) or blockages in the fuel pipes. –  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 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.

–  Pull fuel supply line -arrow- off fuel filter.

–  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 drain tap is closed and cut-off taps are open. –  Operate the remote control -V.A.G 1348/3A-. In doing so, slowly close the shut-off cock -arrow- until pressure gauge indicates a pressure of 4 bar. From here on, do not change position of shut-off tap. –  Empty the fuel tank –  Checking delivery rate again. If the minimum delivery rate is now attained: –  Replace the fuel filter. If the minimum delivery rate is again not attained: –  Remove fuel delivery unit and check filter strainer for soiling. Only when up to now no fault has been detected: –  Renew fuel delivery unit. 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.