SEAT Workshop Service and Repair Manuals

Fuel pressure regulator and retaining pressure: testing

The fuel pressure regulator regulates fuel pressure in function of intake manifold pressure.

The target value for this test depends on the working pressure of the fuel pump, which is approx. 3.0 bar.

Special tools and workshop equipment required

t	Pressure gauge -V.A.G 1318-

t	Adaptor -V.A.G 1318/9-

t	Adaptor -V.A.G 1318/17-

Test process –  Remove the air filter → Fig.

–  Detach the supply line -1- (with white mark) and wipe up spilt fuel with a cloth.   Caution The fuel supply line is under pressure. Before loosening the hose connections, place a cloth around the connection. Then eliminate the pressure by carefully removing the hose.

–  Connect pressure gauge -V.A.G 1318- to the supply line and to the hose to the fuel distributor, with adaptors -V.A.G 1318/9- and -V.A.G 1318/17-. –  Open the flow valve of the pressure gauge. The lever points in the direction of flow. –  Start the engine and let it idle. –  Measure the fuel pressure. Target value: approx. 2.5 bar

–  Remove the vacuum hose from the fuel pressure regulator -arrow-. The fuel pressure should rise to approx. 3.0 bar. –  Switch off the ignition. If the target value is not reached: –  Test the fuel pump flow: → Rep. Gr.20. If the target value is reached: –  Test tightness and retaining pressure, watching the fall in pressure on the pressure gauge. After 10 minutes, there should be a minimum pressure of 2.0 bar. If the retaining pressure falls below 2 bar: –  Start the engine and let it idle.

–  Once the pressure is up, switch off the ignition, closing at the same time the flow valve of pressure gauge -V.A.G 1318- (lever perpendicular to the direction of flow -arrow-). –  Watch the pressure fall in the pressure gauge. If the pressure does not fall: –  Test the fuel pump retaining valve: → Rep. Gr.20. If the pressure falls again:

–  Open the flow valve of pressure gauge -V.A.G 1318- (lever in direction of flow). –  Start the engine and let it idle.

–  Once pressure is up, switch off the ignition, choking off at the same time the return hose (with blue mark) -2-. If the pressure does not fall: –  Replace the fuel pressure regulator → Item. If the pressure falls again: –  Test the line connections, fuel distributor O-rings and injectors for leakage. –  Test the pressure gauge for leakage.   Note! Before removing the pressure gauge, place cloths around the connection.