3.0L TFSI Engine

Fuel Pressure, Checking Holding Pressure In Front of High Pressure Pump

Special tools, testers and auxiliary items required

• Fuel Inj. Pressure Gauge-CIS (V.A.G 1318)

• Adapter (V.A.G 1318/10-12) and Adapter (V.A.G 1318/15)

• Vehicle tester

• Measuring container, fuel-resistant

Procedure






- Follow all test requirements. Refer to => [ Test Conditions ] Initial Inspection and Diagnostic Overview.

There is a risk of injury because the fuel is under high pressure.

• To reduce pressure in the fuel system, lay a clean cloth around the connector and carefully loosen connector.

- Remove the fuel supply hose - 1 - from the high pressure pump and free it up - arrow -.

- Connect the (V.A.G 1318) with the (V.A.G 1318/11) and (V.A.G 1318/15) to the fuel supply hose.






- Push an assisting hose - arrow - onto it and hold it into a measuring container.

- Open the shut-off valve on the pressure gauge.

• The lever points in the direction of flow.

- Connect the tester.

- Turn on the ignition and select the following menu items on the Vehicle Diagnosis Tester :

• OBD

• Engine electronics

• Basic setting

• Empty fuel tank

- Press the Start: The fuel pump starts.

- If the fuel flows without bubbles, close the drain - arrow -, so that the fuel pressure increases.






• The level is perpendicular to the direction of flow.

- Read the fuel pressure on the (V.A.G 1318) :

• Specified value: Approximately 5.5 bar (4.5 to 6.5).

- Press the Stop button.

If the specification is not attained:

- Check the fuel delivery quantity for the fuel pump. Refer to => [ Fuel Pump Delivery Rate, Checking ] Fuel Pump Delivery Rate, Checking.

Checking Holding Pressure

- Check for leaks and constant pressure. Watch the (V.A.G 1318) for a drop in pressure while doing this:

• After 10 minutes there must be a residual pressure of at least 3 bar.

If the holding pressure drops below 3 bar:

• Check the connections between the (V.A.G 1318) and the fuel supply line for leaks.

• Check the (V.A.G 1318) for leaks.

• Check the fuel lines and their connections for leaks.

If no faults are detected:

• Fuel pressure regulator, replacing, refer to => [ Fuel Pressure Regulator ] Service and Repair.

- Repeat the residual pressure check.

If there are still leaks:

• There is a leak at the check valve in the fuel pump: Replace the fuel delivery unit, refer to => [ Fuel Delivery Unit ] Fuel Delivery Unit.

Assemble in reverse order of disassembling. Note the following:

• The ignition must be off.

• Decrease the fuel pressure by opening the drain and letting the fuel run into the measuring container before removing the pressure gauge.

- Remove the (V.A.G 1318) with (V.A.G 1318/11) and (V.A.G 1318/15).

- Attach the fuel supply hose to the high pressure pump. Make sure they are clean and do not leak while doing this.