Transfer Fuel Pump -G6-, CHECKING
Special Tools And Workshop Equipment Required
- Pressure Tester Kit :VAS6550 with Pressure Tester Kit - Hose 2 :VAS6550/2
- Pressure Regulator Valve :VAS6550/4
- Vehicle Diagnostic Tester
- Measuring container, fuel-resistant
A - Check Fuel Delivery Rate
The illustration shows the test sequence on a 2.0L TFSI engine.
-- Follow all test requirements. Refer to TEST CONDITIONS .
-- Release and open the fuel filler door.
-- Remove the cap -2- for the fuel filler -1-.
Ignore item -3-.
Version 1
There is a risk of injury because the fuel is under high pressure.
- To reduce pressure in fuel system, lay a clean cloth around the connector and carefully loosen connector.
-- Disconnect the fuel line -1-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, SEPARATING .
Version 2
There is a risk of injury because the fuel is under high pressure.
- To reduce pressure in fuel system, lay a clean cloth around the connector and carefully loosen connector.
-- Disconnect the fuel line. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, SEPARATING .
Continuation for All Vehicles
-- Connect the :VAS6550 with the :VAS6550/2 to the fuel supply line.
-- Connect the :VAS6550/4 and hold the hose in a fuel-resistant measuring container.
-- Turn the :VAS6550 item -1- on by pressing the On/Off button.
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 the :VAS6550/4 as follows:
-- Open the shut off valves -A and B-.
- The levers point in the direction of flow.
Risk of fuel leak.
- The shut off valve -C- must be closed.
- The lever is perpendicular to the direction of flow.
-- Connect the Vehicle Diagnostic Tester.
-- Turn on the ignition and select the following menu items on the Vehicle Diagnostic Tester:
- OBD
- Engine electronics
- Basic setting
- Empty fuel tank
-- Press Start : The fuel pump starts.
-- Turn the adjusting screw -1- on the :VAS6550/4 to create an initial pressure in the fuel system until the correct initial pressure value is reached.
- Specified value: 4.3 bar (62.3 psi) positive pressure.
-- Do not turn the adjusting screw -1- any more.
-- 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 the Minimum Delivery Rate Is Attained
- The fuel delivery unit with the fuel filter, fuel pressure regulator and fuel supply line is OK.
If Minimum Delivery Quantity is not Obtained, the Following Malfunctions May Be Present:
- Fuel delivery unit faulty.
- The fuel filter, integrated in the sealing flange fuel pressure regulator is blocked or faulty.
- Fuel supply line is pinched.
To locate the fault in more detail, perform the "pressure test in the fuel supply line", described as follows.
B - Pressure Test in the Fuel Supply Line
- Connect the measuring setup as if measuring the delivery quantity.
- Vehicle Diagnostic Tester still connected.
-- Turn the :VAS6550 item -1- on by pressing the On/Off button.
-- Open the shut off valves -A and B-.
- The levers point in the direction of flow.
Risk of fuel leak.
- The shut off valve -C- must be closed.
- The lever is perpendicular to the direction of flow.
-- Press Start on the display of the Vehicle Diagnostic Tester: The fuel pump starts.
-- If the fuel flows without bubbles, close the drain -B-, so that the fuel pressure increases.
- The lever is perpendicular to the direction of flow.
-- Read the fuel pressure in the :VAS6550 :
- Specified value: 5.0 to 8.0 bar (72.5 to 116 psi).
-- Press the Stop button.
If Specified Value Is Obtained, Although the Fuel Delivery Unit is Not OK.
- The fuel filter integrated in the sealing flange is blocked or the fuel supply line is crushed.
If the Specification is Not Attained
- The fuel delivery unit or the fuel pressure regulator integrated in the fuel pressure regulator is faulty.
C - Checking Residual Pressure
-- Watch the pressure fall on the :VAS6550 while checking the holding pressure and checking for leaks:
- After 10 minutes there must be a residual pressure of at least 3 bar (43 psi).
If the Residual Pressure Drops Below 3 bar (43 psi):
- Check fuel lines and their connections for leaks.
- There is a leak at the check valve in the fuel pump: Replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING .
Assembling
Assembly is performed in the reverse order of disassembly, noting the following:
- The ignition must be off.
Decrease the fuel pressure by opening the drains -B, C- and letting the fuel run into the measuring container before removing the pressure gauge -1-.
-- Remove the :VAS6550 with the connecting lines.
-- Attach the fuel supply line so that it clicks into place.
-- Press the fuel supply line on again and pull to make sure the connector coupling is engaged correctly.