SEAT Workshop Service and Repair Manuals

Checking delivery pressure of fuel pump Special tools and workshop equipment required t  Pressure gauge -VAS 6551-, see equivalent → Anchor t  Hose adapter -VAS 6551/1- t  Hose adapter -VAS 6551/2- t  Vehicle diagnostic, testing and information system -VAS 505X-, see equivalent → Anchor Test prerequisite: l  Fuses must be OK. l  Battery voltage at least 12 V l  This measurement does not depend on the fuel level but a minimum level of 5 l is necessary. l  Ensure that vehicle is placed on a level surface. l  Ensure that fuel hoses and lines in engine compartment and on underbody are not closed through damage (kinks). l  All electrical consumers, e.g. lights and rear window heating, must be switched off.   WARNING Fuel supply line is pressurised. Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection. Checking process: »Carry out the following work sequence« –  Remove engine cover → Chapter –  Push connector coupling on fuel filter → Item, fuel supply line to high-pressure pump, forwards onto filter connection. Press catches in and hold, pull fuel supply line from fuel filter. –  Collect escaping fuel with a cleaning cloth.

–  Connect pressure tester -VAS 6551- to lines -VAS 6551/1- and -VAS 6551/2- in fuel circuit. –  Switch on pressure tester -VAS 6551- by pressing On/Off button.

–  Open shut-off taps „A“ and „B“ of pressure tester -VAS 6551- and close shut-off tap „C“. –  Connect the Vehicle diagnostics tester -VAS 505X- and perform the guided function „Fuel pump: Actuate (Fuel pump: check “.   Note The fuel pump is now activated for 30 seconds. –  Read current pressure on pressure tester -VAS 6551-. Specification: minimum 4.5 bar. –  Start engine and run at idling speed. –  Read current pressure on pressure tester -VAS 6551-. Specification: minimum 4.5 bar. –  Place pressure tester -VAS 6551- onto windscreen so that it can be read from inside of vehicle. –  Increase idling speed to 2500 rpm. –  Read pressure on pressure tester -VAS 6551-. Specification: min. 4.5 bar If the specified value is not reached, the check is to be repeated at the filter input. This checks whether the fuel filter is clogged. –  When the supply pressure falls completely or sporadically, check the time of the voltage supply → Chapter and power consumption → Chapter of the fuel supply unit. –  Reconnect fuel supply line to high-pressure pump → Item at fuel filter. Ensure for secure engagement of coupling. –  Push the quick release coupling on fuel filter → Item fuel delivery line to fuel filter, forwards onto filter connection. –  Press catch in and hold, pull fuel supply line from fuel filter. –  Collect escaping fuel with a cleaning cloth.

–  Connect pressure tester -VAS 6551- with lines -VAS 6551/1- and -VAS 6551/2- to open ends. –  Perform pressure measurement as in previous check. –  Pressure value should now be 4.6 bar minimum. t  If specified pressure values are obtained t  If difference in measured pressure value (before filter and after filter) ≥0.4 bar –  The fuel filter must be renewed → Chapter. t  If specified pressure values are not obtained

t  Does the supplementary fuel filter (when fitted) -4- have to be checked in the fuel tank. t  For this, a measurement must be performed directly on fuel delivery unit. »Carry out the following work sequence« –  Reconnect plug-in coupling to fuel filter. Ensure for secure engagement of coupling.

–  Raise cover of fuel delivery unit.

–  First check that connector -arrow- is fitted securely by pulling connector without pressing catch. The connector can cause a fault if it has not been fitted correctly.

–  Pull fuel supply line (black or black marking) -4- off fuel delivery unit. –  Collect escaping fuel with a cleaning cloth.

–  Connect connection -A- of pressure tester -VAS 6551- with line -VAS 6551/1- to open end of fuel delivery unit. –  Open shut-off taps „B“ + „C“ of pressure tester -VAS 6551-. –  Switch on pressure tester -VAS 6551- by pressing On/Off button. –  Connect the Vehicle diagnostics tester -VAS 505X- and perform the guided function „Fuel pump: Actuate (Fuel pump: check “.   Note The fuel pump is now activated for 30 seconds. –  Read current pressure on pressure tester -VAS 6551-. Specification: 7.2 ± 0.5 bar. If the specified pressure is reached

–  Replace supplementary fuel filter together with integrated pressure regulator. If the supply pressure is not achieved and the supply pressure falls completely or sporadically again, the following malfunctions are possible: t  Battery voltage below 12.5 Volts (connect battery charger) t  Fuel delivery rate of fuel pump too slow. check → Chapter. t  Voltage supply of fuel pump not ok. Check → Chapter. t  Current consumption of fuel pump too low. Check → Chapter. t  Fuel delivery unit filter strainer soiled. In order to check it, remove the fuel delivery unit → Chapter. t  Quick-release coupling in the fuel delivery unit defective. In order to check it, remove the fuel delivery unit → Chapter.