A - Check Fuel Delivery Rate

WARNING: This page is about a different car, the 2016 Audi A6 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

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NOTE:

The test sequence is shown on a 3.0L TDI engine as an example.

-- Follow all test requirements. Refer to TEST CONDITIONS .

-- Open the fuel filler door.

-- Remove the fuel filler cap -arrow-.

WARNING:

There is a risk of burns due to hot fuel.

The temperature of the fuel lines or fuel may reach 100 °C (212 °F) after stopping the engine. Let the fuel cool down before opening any line connections otherwise there is a danger of scalding.
Wear safety gloves
Wear protective eyewear.

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.

-- Loosen the hose clamp -2- and remove the fuel supply hose -3- to the high pressure pump from the fuel supply line -1-.

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NOTE:

If the separating point is not accessible, the air filter housing must be removed. Refer to AIR FILTER HOUSING, REMOVING AND INSTALLING .

-- Connect the :VAS6551 to the fuel supply line using the :VAS6551/5-2 and secure with a hose clamp.

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-- Attach the :VAS6551/6 and hold the hose in a fuel-resistant measuring container.

-- Switch on the :VAS6551 -1- by pressing the On/Off button.

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NOTE:

To measure the fuel delivery rate, there must be an initial pressure inside the fuel supply line against which the fuel pump must work during the measuring. This initial pressure is adjusted using the :VAS6551/6 as follows:

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

The levers point in the direction of flow.

CAUTION:

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
Transfer Fuel Pump Test

-- Press Start : The fuel pump starts.

-- Turn the adjusting screw -1- on the :VAS6551/6 to create an initial pressure in the fuel system until the correct initial pressure value is reached.

Courtesy of AUDI OF AMERICA, LLC

Specified value: 4 bar (58 psi) 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: 750 cm³ /15 s.

If the Minimum Delivery Rate is Attained:

Fuel supply line with fuel supply line and fuel pump are OK.
However, there may be a malfunction in the fuel return. For Fault Finding, perform an "Entire system pressure test". Refer to Transfer Fuel Pump -G6-, CHECKING .

If Minimum Delivery Quantity is not Obtained, the Following Malfunctions may be Present:

The fuel pump or fuel pressure regulator in the fuel tank is faulty.
The fuel filter is clogged or the fuel line is kinked

NOTE:

To locate the fault in more detail, perform the "pressure test in the fuel supply line", described as follows.