Transfer Fuel Pump -G6-, Checking, TFSI Vehicles
Special tools and workshop equipment required
- Pressure Tester Kit :VAS6550 with Pressure Tester Kit - Hose 2 :VAS6550/2
- Pressure Tester Kit - Adapter Set :VAS6550/3
- Pressure Regulator Valve :VAS6550/4
- Vehicle Diagnostic Tester
- Fuel-Resistant Measuring Container
A - Checking Fuel Delivery Rate
-- Follow all test conditions. Refer to TEST CONDITIONS .
-- Open the fuel filler door.
-- Remove the fuel filler cap -arrow-.
-- Remove the engine cover. Refer to ENGINE COVER, REMOVING AND INSTALLING .
1.4L/3.0L TFSI Vehicles:
There is a risk of injury because the fuel is under high pressure.
- To reduce the pressure in the fuel system, lay clean cloths around the connection point and carefully loosen the connection point.
-- Disconnect the fuel hose -1-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, DISCONNECTING .
-- Connect the :VAS6550 to the fuel supply line with the :VAS6550/2 .
-- Connect the :VAS6550/4 and hold the hose in a fuel-resistant measuring container.
1.8L/2.0L TFSI Vehicles
The fuel system is under pressure.
Risk of injury from fuel spraying out.
- Wear protective eyewear.
- Wear safety gloves.
- Reduce the pressure: Place clean cloths around the connection point and carefully open the connection point.
-- Disconnect the fuel hose -1-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, DISCONNECTING .
-- Connect the :VAS6550 to the fuel supply hose using the :VAS6550/2 .
-- Connect the :VAS6550/4 and hold the hose in a fuel-resistant measuring container.
Continuation for All Vehicles
-- Switch on the :VAS6550 -1- by pressing the On/Off button.
To measure the fuel delivery rate, an initial pressure must be created in the fuel line which the fuel pump must work against during measurement. Adjust the initial pressure using the Pressure Regulator Valve :VAS6550/4 as follows:
-- Open the shut-off valves -A and B-.
- The lever points in the flow direction.
Risk of fuel leak.
- The shut-off valve -C- must be closed.
- The lever is perpendicular to the flow direction.
-- Connect the Vehicle Diagnostic Tester.
-- Switch the ignition on.
-- Select the OBD mode.
- Select 0001 - engine electronics .
- Select basic setting in the control module basic setting menu item.
- Select Empty fuel tank on the list.
-- 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: 4.5 bar (65.27 psi) pressure.
-- Do not turn the adjusting screw -1- any farther.
-- Press the Stop button.
-- Empty the 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 fuel delivery rate in the measuring container.
- 4-Cylinder specified value: minimum delivery rate 400 cm3 /15 s.
- 6-Cylinder specified value: minimum delivery rate 600 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 are OK.
If the Minimum Delivery Rate Is Not Obtained, the Following Malfunctions May Be Present
- Fuel delivery unit with integrated fuel filter is faulty.
- Fuel pressure regulator in the fuel delivery unit is faulty.
- Fuel supply line is crushed.
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 fuel delivery rate.
- Vehicle Diagnostic Tester still connected.
-- Switch on the :VAS6550 -1- by pressing the On/Off button.
-- Open the shut-off valves -A and B-.
- The lever points in the flow direction.
Risk of fuel leak.
- The shut-off valve -C- must be closed.
- The lever is perpendicular to the flow direction.
-- Press Start on the Vehicle Diagnostic Tester display: The fuel pump starts running.
-- If the fuel flows without bubbles, close the drain -B-, so that the fuel pressure increases.
- The lever is perpendicular to the flow direction.
-- Read the fuel pressure in the :VAS6550 :
- Specified value: 6.0 to 8.0 bar (87.02 to 116.03 psi).
-- Press the Stop button.
If the specified value is obtained, although the fuel delivery rate is not OK.
- Fuel filter in the fuel delivery unit is plugged of the fuel supply line is crushed.
If the specified value is not attained
- Fuel delivery unit or fuel pressure regulator in the fuel tank is faulty.
C - Checking Residual Pressure
-- Watch the pressure fall on the :VAS6550 while checking the residual pressure and checking for leaks:
- There still must be a pressure of at least 3 bar (43.51 psi) after 10 minutes.
If the Residual Pressure Drops Below 3 bar (43.51 psi)
- Check the fuel lines and their connections for leaks.
- The fuel pump check valve in the fuel pump leaks: replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING, TDI VEHICLES .
Assembling
Assemble in the reverse order of removal. Note the following:
- The ignition must be off.
Decrease the fuel pressure by opening the shut-off valves -B and 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.