Fuel Pump Delivery Rate, Checking

Fuel Pump Delivery Rate, Checking

Special tools, testers and auxiliary items required

• Pressure Tester (VAS 6550) with Hose (VAS 6550/1) and Hose (VAS 6550/2)

• Vehicle tester

• Measuring container, fuel-resistant

Procedure






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

- Open the fuel filler door.

- Remove the fuel filler cap - arrow -.








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.

- Push back the boot and disconnect the fuel line - 1 -.

- First push the hose coupling - 2 - downward - arrow A -, then press the release buttons - arrows B -.

- Remove the hose coupling with the release buttons pressed.

- Connect the (VAS 6550) to the fuel supply line using (VAS 6550/2).






- Connect the (VAS 6550/1) and hold it inside a fuel resistant container.








Risk of fuel leak.

• Make sure that the drain - C - is closed.

• The level is perpendicular to the direction of flow.

- Open the drains - A and B -.

• The levers point 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

• In order to measure the fuel delivery rate, there must be an initial pressure inside the fuel line against which the fuel pump must work during the measuring. Adjust the initial pressure using (VAS 6550) as follows:

- Press Start and create an initial pressure in the fuel system: the fuel pump starts to run and slowly close the shut-off valve - B - on the pressure tester.






• Specified value: 4 bar positive pressure.

- From this point on do not move position of shut-off valve.

- Press the Stop button.

- Empty measuring container.

- To measure, press the Start button again and let the fuel pump run for 15 seconds.

- After 15 seconds, press the Stop button.

- Check the amount of fuel in the measuring container.

• Specified value: Minimum delivery rate 800 cm3/15 s.

If minimum delivery quantity is not obtained, the following malfunctions may be present:

• The fuel lines are pinched.

• The fuel filter is clogged.

• The fuel pump is faulty.

Assemble in reverse order of disassembling. Note the following:

- Attach the fuel line so that it clicks into place.

- Press the fuel line on again and pull to make sure the connection is engaged correctly.