SEAT Workshop Service and Repair Manuals

Checking fuel pressure regulator and holding pressure

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. This is approx. 3.0 bar

Special tools and workshop equipment required

t	Pressure gauge -V.A.G 1318-

t	Adapter -V.A.G 1318/10-

t	Adapter -V.A.G 1318/11-

t	Hose adapter -V.A.G 1318/16-

t	Pliers for flexible clamps -T20029-

Test sequence –  Pull fuel pump fuse No. 40 out of fuse holder. –  Remove air cleaner → Fig..

–  Pull off supply pipe/hose -1- (with white marking) and collect fuel that leaks out with a cloth.   Caution Fuel supply pipes are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

–  Connect pressure gauge -V.A.G 1318- with adapter -V.A.G 1318/10- to supply hose -1- and with adapter -V.A.G 1318/11- and hose adapter -V.A.G 1318/16- to supply pipe. –  Open shut-off tap on pressure gauge. The handle points in direction of flow. –  Insert fuel pump fuse No. 40 into fuse holder. –  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. → Chapter If the specification is obtained: –  Check for leaks and holding pressure by observing pressure drop on gauge. After 10 minutes there must 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.

–  Switch ignition off after the pressure has built-up. At the same time close pressure measured device cut-off tap (handle cross through-flow direction -arrow-). –  Observe pressure drop on gauge. If the pressure does not drop: –  Check fuel pump non-return 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 run at idling speed.

–  Switch ignition off after the pressure has build-up. At the same time clampoff 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.