Fuel Pressure and Residual Pressure Before High Pressure Pump, Checking

Fuel Pressure and Residual Pressure before High Pressure Pump, Checking

Special tools, testers and auxiliary items required

• Fuel inj. Pressure Gauge-cis (V.A.G 1318)

• Adapter (V.A.G 1318/11)

• Adapter (V.A.G 1318/12)

• Remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-3)

• Measuring container, fuel-resistant

Test conditions:

• Battery voltage at least 12.5 Volts.

• Fuse on fuse panel (S228) (position 28) OK.





• Fuel Pump (FP) Control Module (J538) OK; checking





• Fuel filter OK.

• Fuel tank minimum 1/4 full.

Test Sequence

- Switch off ignition.

Sedan:

- Remove carpeting in luggage compartment.

- Fold forward the right backrest of rear seat, if necessary.

Wagon:

- Remove left 1/3 backrest.

- Remove left side trim in luggage compartment and dirt tray.

All:

- Remove locking flange cover - arrows -.





- Disconnect electrical harness connector - arrow - at locking flange.





- Connect remote control (V.A.G 1348/3 A) with connection (V.A.G 1348/3-3) to contact - 1 - using an adapter cable from the connector test set (V.A.G 1594 C).





- Using insulating tape, tape over the second contact of adapter cable (V.A.G 1348/3-3) to prevent a short circuit - arrow -.

- Connect contact - 4 - to vehicle Ground (GND) using a jumper cable from connector test set (V.A.G 1594 C ).

- Connect alligator clip to vehicle battery (positive).

- Remove fuel filler cap from fuel filler tube.

- Remove engine cover - arrows -.





CAUTION!
Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

- Disconnect fuel supply line - arrow -.





- Connect pressure gauge (V.A.G 1318) to fuel supply line using adapter (V.A.G 1318/11 ) and (V.A.G 1318/12).





- Connect assisting hose - arrow - to Pressure Gauge (V.A.G 1318) and hold it in a measuring container.

- Open shut-off valve of pressure gauge (V.A.G 1318 ). The lever points in direction of flow.

- Bleed fuel system by pressing remote control briefly.

- Close shut-off valve on Pressure Gauge (V.A.G 1318 ). Lever stands perpendicular to direction of flow - arrow -.





- Hold switch of the remote control until no more pressure increase is observed on the Pressure Gauge (V.A.G 1318).

• Specified value: approximately 6 bar (3 to 7 bar) positive pressure.

If specification is not obtained:

- Check delivery rate of fuel pump.

Residual Pressure

- Check for leaks and residual pressure by observing pressure drop on Pressure Gauge (V.A.G 1318).

• After 10 minutes there must be a residual pressure of at least 3.75 bar.

If the residual pressure drops below 3 bar:

• Check connection between fuel Pressure Gauge (V.A.G 1318 ) and fuel line for leaks.

• Check Pressure Gauge (V.A.G 1318) for leaks.

• Check fuel lines and their connections for leaks.

• Replace fuel filter with integrated fuel pressure regulator. Then repeat test.

• If the fuel filter is OK, replace fuel pump.

Assembly is in reverse order of removal, noting the following:

- Switch off ignition.





• Before disconnecting pressure gauge, release pressure by opening shut-off valve. Hold collecting container in front of hose.

- Retighten fuel supply line (ensure cleanliness).

Tightening Specifications