SEAT Workshop Service and Repair Manuals

Fuel pressure regulator and re-tention 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 fuel pressure 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 supply hose -1- (with white mark) and wipe up spilt fuel with a cloth.   Warning The fuel system is under pressure. Before opening the system, place a cloth around the point of connection. Then, eliminate the pressure by carefully loosening the connection.

–  Attach pressure gauge -V.A.G 1318- to the supply line and to the hose to the fuel distributor, using 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 run it at idle. –  Measure the fuel pressure Target value: approx. 2.5 bar –  Remove the vacuum hose from the fuel pressure regulator. The fuel pressure should rise to approx. 3.0 bar –  Switch off the ignition. If the target value is not reached: –  Test the flow of the fuel pump → Chapter If the target value is reached: –  Test leakage and the retention 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 retention pressure falls below 2 bar: –  Start the engine and run it at idle.

–  When the pressure has been created, switch off the ignition, closing at the same time the flow valve of the pressure gauge V.A.G. 1318 (lever perpendicular to direction of flow -arrow-). –  Watch the fall in pressure in the pressure gauge. If the pressure does not fall: –  Test the fuel pump retention valve → Chapter If the pressure descends again:

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

–  When the pressure has been created, switch off the ignition, at the same time cutting off the return hose (with blue mark) -2-. If the pressure does not fall: –  Replace the fuel pressure regulator → Item If the pressure descends again: –  Test leakage of the connecting lines, O-rings of the fuel distributor and injectors. –  Test leakage of the pressure gauge.   Note! Before removing the pressure gauge place cloths around the point of connection.