Transfer Fuel Pump -G6-, CHECKING, 5-CYLINDER TFSI VEHICLES

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Special tools and workshop equipment required

Pressure Tester Kit: VAS6550 with Pressure Tester Kit - Hose 1: VAS6550/1 and : VAS6550/2

Fig 1: Identifying Pressure Tester Kit VAS 6550
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Pressure Tester Kit - Regulator Valve: VAS6550/4

Fig 2: Identifying Pressure Regulator Valve VAS 6550/4
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Vehicle Diagnostic Tester
A measuring container that holds at least 3 liters and is fuel resistant (commercially available)
Emergency refueling funnel from the vehicle tool kit

A - Checking Fuel Delivery Rate

Fig 3: The Fuel Filler Cap

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-- Observe all test conditions. Refer to TEST CONDITIONS .

-- Open the fuel filler door.

-- Remove the fuel filler neck cap -arrow-.

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CAUTION:

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 line -1-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, DISCONNECTING .

-- Connect the Pressure Tester Kit: VAS6550 to the fuel supply line with the Pressure Tester Kit - Hose 2: VAS6550/2 .

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-- Attach the Pressure Tester Kit - Regulator Valve: VAS6550/4 and hold the hose in a large, fuel-resistant measuring container.

-- Switch on the Pressure Tester Kit: VAS6550 -1- by pressing the On/Off button.

Fig 4: Identifying Shut-Off Valves A And B On Pressure Tester Kit

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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. The initial pressure is adjusted using the Pressure Tester Kit - Regulator Valve: VAS6550/4 as follows:

-- Open the shut-off valves -A and B-.

The levers point in the flow direction.

-- 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

-- Push Start : the fuel pump starts.

-- To generate the initial pressure in the fuel system, turn the adjusting screw -1- on the Pressure Tester Kit - Regulator Valve: VAS6550/4 until the correct initial pressure value is reached.

Fig 5: Identifying Pressure Regulator Valve Adjusting Screw

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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.

Specified value: minimum delivery rate 700 cm³ /15 s.

If the Minimum Delivery Rate is Attained:

The fuel delivery unit and the fuel supply line are OK.

If the Minimum Delivery Rate is Not Obtained, it May be Due to the Following Malfunctions:

Fuel delivery unit faulty.
Fuel supply line is crushed.

To more accurately locate the malfunction, perform the "pressure test in the fuel supply line" described in the following.

B - Pressure Test in the Fuel Supply Line

Fig 6: Identifying Shut-Off Valves A And B On Pressure Tester Kit

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Set up the equipment as if measuring for the fuel delivery rate.
Vehicle Diagnostic Tester is still connected.

-- Switch on the Pressure Tester Kit: VAS6550 -1- by pressing the On/Off button.

-- Open the shut-off valves -A and B-.

The levers point in the flow direction.

-- Press Start on the Vehicle Diagnostic Tester display: the fuel pump starts running.

-- If the fuel flows without bubbles, close the shut-off valve -B- so that the fuel pressure increases.

The lever is perpendicular to the flow direction.

-- Read the fuel pressure on the Pressure Tester Kit: VAS6550 :

Specified value: minimum 6.0 bar (87.02 psi)

If the Specified Value Is Obtained, Even Though the Fuel Delivery Rate was not OK:

The fuel delivery unit integrated fuel filter is blocked or the fuel supply line is crushed.

If the Specified Value Is Not Attained:

Fuel delivery unit faulty.

C - Checking Residual Pressure

-- Check the residual pressure and also for leaks by monitoring the decrease in pressure on the Pressure Tester Kit: VAS6550 :

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 check valve in the fuel pump leaks: replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING .

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-.

Fig 7: Identifying Shut-Off Valves A And B On Pressure Tester Kit
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-- Remove the Pressure Tester Kit: VAS6550 with the connecting lines.

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

-- Press on the fuel supply line again and pull it to make sure the connector coupling is engaged correctly.