SEAT Workshop Service and Repair Manuals

Fuel system and retention pressures: verification

Special tools and workshop equipment required

t	Adaptor cable -SAT 1348/3-3-

t	Pressure gauge -V.A.G 1318-

t	Adapter -V.A.G 1318/1-

t	Adapter -V.A.G 1318/11-

t	Adapter -V.A.G 1318/17-

t	Adapter -V.A.G 1318/23-

t  -V.A.G 1318/9-

t  Remote control -V.A.G 1348/3A- The fuel pressure regulator regulates the fuel pressure depending on intake manifold pressure. This makes sure the pressure reduction at the injectors remains the same for any given engine speed or load. Test conditions l  Fuel pump relay -J17- OK. l  Fuel pump OK l  Fuel filter OK l  Min. battery voltage 11.5 V   Caution Fuel supply pipes are under pressure Before loosening the fuel line connections, place a clean cloth around the connection. Then release pressure by carefully loosening the connection. Verification process –  Open the fuel tank cap briefly to reduce the pressure.

–  Remove fuel supply pipe -1-, press buttons on fuel hose couplings to do this.

–  Connect pressure gauge -V.A.G 1318- with Adapter -V.A.G 1318/9- and -V.A.G 1318/17- to the fuel supply pipe. –  Open shut-off tap on pressure gauge. The handle points in direction of flow. –  Start the engine and let it run at idle. –  Measure fuel pressure. Specification: approx. 2.5 bar

–  Pull the vacuum hose -1- off fuel pressure regulator -2-. The fuel pressure should increase. Specification: approx. 3 bar. –  Shut off engine. If the ideal value is not measured: –  Switch ignition off. –  Check quantity supplied by fuel pump → Chapter. If the specifications are obtained: –  Switch ignition off. –  Observe pressure drop on gauge. After 10 minutes the pressure must not drop below 2 bar. If the pressure drops below 2 bar:

–  Start the engine and run at idling speed until a pressure of approx. 3 bar has been built up, stop engine and close off the cut-off tap (lever at right angle to direction of flow -arrow-). –  Observe pressure drop on gauge. After 10 minutes the pressure must not drop below 2 bar. If the pressure does not drop: –  Check the fuel pump retention valve → Chapter. If the pressure drops again:

–  Open pressure gauge -V.A.G 1318- shut-off tap (handle in direction of flow). –  Start the engine and let it run at idle. –  Switch ignition off after the pressure has built up. At the same time clamp off the return hose (with blue marking). If the pressure does not drop: –  Replace fuel pressure regulator. If the pressure drops again: –  Ensure that there is no leaks in the tube connections, the joints and the O-rings of the fuel rail and the injectors. –  Ensure that the pressure gauge tester -V.A.G 1318- and all of the adaptors are airtight.   Note! Before removing the pressure gauge, reduce the pressure by opening the cut-off tap. On doing so, place a container where the pipes will be opened.