Transfer Fuel Pump -G6-, CHECKING, VEHICLES WITH 5-CYLINDER ENGINE

Special tools and workshop equipment required 

• Pressure Tester Kit: VAS6550  with Pressure Tester Kit - Hose 1: VAS6550/1  and : VAS6550/2 
• Pressure Regulator Valve: VAS6550/4 
• 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

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

-- Open the fuel filler door.

-- Insert the emergency refueling funnel -1- from the vehicle tool kit all the way into the filler neck -arrow-.

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

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

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

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

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

• The levers point in the flow direction.

-- Connect the Vehicle Diagnostic Tester.

-- Switch the ignition on.

-- Select the OBD  mode.

• Select 01 - engine electronics  .
• Select output diagnostic test mode  in the control module OBD menu item.
• Select Fuel pump electronics  from the list.

-- Press Start  .

• The fuel pump runs in the first 10 seconds consistently high and then 20 seconds at 90%.

-- To generate the initial pressure in the fuel system after 10 seconds, turn the adjusting screw -1- on the : VAS6550/4  until the correct initial pressure value is reached.

• Specified value: 4.5 bar 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 30 seconds.

TIP:

-- The output diagnostic test mode ends after 30 seconds.

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

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

B - Pressure test in the fuel supply line

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

-- Switch on the : VAS6550  -item 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 : VAS6550  :

• Specified value: minimum 6.0 bar

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 : VAS6550  :

• There still must be a pressure of at least 3 bar after 10 minutes.

If the residual pressure drops below 3 bar:

• 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.

-- Remove the : 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.