SEAT Workshop Service and Repair Manuals

Fuel pressure regulator and holding pressure checking

The fuel pressure regulator regulates the fuel pressure depending on intake manifold pressure.

The specification for the check is dependent upon the working pressure of the fuel pump, approx. 3.0 bar.

Special tools and workshop equipment required

t	Pressure gauge -V.A.G 1318-

t	Adapter -V.A.G 1318/9-

t	Adapter -V.A.G 1318/17-

Test sequence

–  Pull off the supply hose -1- (with white marking) and wipe up spilt fuel with a cloth.   Caution Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.

–  Connect pressure gauge -V.A.G 1318- to fuel supply line and to hose to fuel rail using adapters -V.A.G 1318/9- and -V.A.G 1318/17-. –  Open shut-off tap on pressure gauge. The handle points in direction of flow. –  Start the engine and run at idling speed. –  Measure fuel pressure.    Specification: Approx. 2.5 bar

–  Pull vacuum hose off fuel pressure regulator -arrow-. The fuel pressure must increase to approx. 3.0 bar –  Switch off ignition. If the specification is not obtained: –  Check quantity supplied by fuel pump → Rep. Gr.20. If the specification is obtained: –  Check for leaks and holding pressure by observing pressure drop on gauge. After 10 minutes, there should be a residual pressure of at least 2.0 bar. If the holding pressure drops below 2 bar: –  Start the engine and run at idling speed.

–  When pressure has been created, shut off ignition, at the same time closing the flow valve on pressure gauge -V.A.G 1318- (handle in direction of flow -arrow-). –  Observe pressure drop on gauge. If the pressure does not drop: –  Check fuel pump non-return valve → Rep. Gr.20. If the pressure does not drop:

–  Open pressure gauge -V.A.G 1318- shut-off tap (handle in direction of flow). –  Start the engine and run at idling speed.

–  Switch ignition off after the pressure has built up. At the same time clamp off the return hose (with blue marking) -2-. If the pressure does not drop: –  Renew fuel pressure regulator → Item. If the pressure drops again: –  Check pipe connections, O rings on fuel manifold and injectors for leaks. –  Check pressure gauge for leaks.   Note! Before removing pressure gauge place a cloth around the connections to be loosened.