Transfer Fuel Pump -G6-, Checking, Vehicles With 5-Cylinder Engine: Notes

WARNING: This page is about a different variant/trim than selected.

Special Tools And Workshop Equipment Required

Pressure Tester Kit:VAS6550 with Pressure Tester Kit - Hose 1:VAS6550/1 and Pressure Tester Kit - Hose 2:VAS6550/2
Pressure Regulator Valve:VAS6550/4
Vehicle Diagnostic Tester
Fuel-Resistant Measuring Container

A - Check Fuel Delivery Rate

Fig 1: Identifying Cap -2-

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

-- Release and open the fuel filler door.

-- Clean the area around the fuel filler neck.

-- Remove the cap -2- for the fuel filler -1-.

NOTE:

Ignore -3-.

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WARNING:

Risk of injury due to the fuel being 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 line -1-. Disconnect the connector couplings. Refer to CONNECTOR COUPLINGS, DISCONNECTING .

NOTE:

Ignore -2-.

-- Connect the :VAS6550 to the fuel supply line with the :VAS6550/2 .

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-- Connect the :VAS6550/4 and hold the hose in a fuel-resistant measuring container.

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

Fig 2: Identifying Shut-Off Valves A And B On Pressure Tester Kit

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NOTE:

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. Set the initial pressure using the :VAS6550/4 as follows:

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

The levers point in the flow direction.

CAUTION:

Risk of fuel leaking.

The shut-off valve -C- must be closed.
The lever is perpendicular to 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
Output diagnostic test mode
Fuel Pump Electronics

-- Push 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.

Fig 3: 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 push the Start button again and let the output diagnostic test mode run. Let it run for at least 30 seconds.

-- Then press the Stop button.

-- Check the fuel delivery rate in the measuring container.

Specified value: minimum delivery rate 1300 cm³ /30 s.

NOTE:

This output diagnostic test mode starts the fuel pump for 30 seconds. Then the fuel pump is switched off.

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.

NOTE:

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 4: 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.
The Vehicle Diagnostic Tester is still connected.

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

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

The levers point in the flow direction.

CAUTION:

Risk of fuel leaking.

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 shut-off valve -B- so that the fuel pressure increases.

The lever is perpendicular to the flow direction.

-- Read the fuel pressure on the :VAS6550 :

Specified Value: minimum 6.0 bar (87 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

-- Watch the pressure decrease on the :VAS6550 while checking the residual pressure and checking for leaks:

There still must be a pressure of at least 3 bar (43 psi) after 10 minutes.

If the Residual Pressure Drops Below 3 bar (43 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 .