Fuel Delivery Rate, Checking

WARNING: This page is about a different car, the 2009 Volkswagen GTI and 2008 Volkswagen GTI. However, it is still accessible from the selected car via links, so may be relevant.

-- Remove the rear seat bench. Refer to Removal and Installation .

-- Remove the cover -1- and fuel pump control module -J538- -2- from the fuel delivery unit.

Fig 1: Identifying Cover With Fuel Pump Control Module J538

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- First, pull on the connector -arrow- without pressing the retainer to make sure it is connected securely. If the connector was not connected correctly, it could cause a fault.

Fig 2: Identifying Fuel Pump Control Module Connector

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Disconnect the connector.

-- Check the contacts on the connector and the fuel delivery unit for damage.

-- Install the test instrument adapter/DSO (5-pin) -VAS 5565- between the connectors on the cover and the fuel delivery unit.

Fig 3: Identifying Remote Control V.A.G 1348/3A Connected To Test Instrument Adapter/DSO (5-Pin) VAS 5565 And Battery Plus (+)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Connect the remote control -V.A.G 1348/3A- to the test instrument adapter/DSO (5-pin) -VAS 5565- and the battery positive terminal clamp in the engine compartment.

NOTE:

This step allows the fuel pump to run when the engine is not running.

WARNING:

The fuel supply line is under pressure. Always wear protective eyewear and protective clothing to prevent injuries and fuel from coming in contact with your skin. Wrap a cloth around the connection before removing a fuel hose. Remove the hose connection carefully to release the pressure.

-- Disconnect the supply line (metal coupling) -arrow- and collect any leaking fuel with a cloth.

Fig 4: Identifying Supply Line

Courtesy of VOLKSWAGEN UNITED STATES, INC.

NOTE:

Press in the securing ring to disengage the fuel line.

-- Connect the pressure tester -VAS 6550- to the fuel supply line using the hose -VAS 6550/2-. Hold the other hose -VAS 6550/1- in a measuring container.

Fig 5: Identifying Pressure Tester VAS 6550 And Fuel Supply Line Using Hose VAS 6550/2

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Make sure the drain is closed and the shut-off levers are open.

WARNING:

Danger of spraying. Always wear protective eyewear and protective clothing to prevent injuries and fuel from coming in contact with your skin. Hold container in front of free connection of pressure measuring device.

-- Operate the remote control -V.A.G 1348/3A-. Slowly close the shut-off lever -arrow- until the pressure tester shows 4 bar. From this point on do not move the position of the shut-off lever.

-- Empty the measuring container.

-- The fuel delivery rate of the fuel pump is dependent on battery voltage. So, connect the multi-meter -V.A.G 1715- to wires -1 and 5- of the test instrument adapter/DSO (5-pin) -VAS 5565-.

Fig 6: Identifying Multi-Meter V.A.G 1715 Connected To Wires And Of Test Instrument Adapter/DSO (5-Pin) VAS 5565

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Operate the remote control for 60 seconds and simultaneously measure the voltage on the fuel pump.

-- Compare the quantity of fuel delivered with specification.

Fig 7: Identifying Graph Of Voltage Versus Delivery Rate

Courtesy of VOLKSWAGEN UNITED STATES, INC.

*) Minimum delivery rate cm 3 /60 s

**) Voltage of the fuel pump with engine idling and the pump is on.

Example:

During the test, a voltage of 10.5 volts is measured. This results in a minimum delivery quantity of approximately 1200 cm 3 /60 s.

If the Specification is Not Obtained

-- Check the fuel lines for possible restrictions (kinks) or blockages.

If no malfunction can be found:

-- Remove the cap for the fuel filler neck and repeat the test. If the fuel delivery quantity is now reached, check the fuel tank ventilation.

If the Specification is Again Not Obtained

-- Check the fuel filter as follows:

WARNING:

-- Disconnect the fuel supply line -arrow- from the fuel filter.

Fig 8: Identifying Fuel Supply Line At Fuel Filter

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Connect the pressure tester -VAS 6550- to the fuel supply line using the hose -VAS 6550/1-. Hold the other hose -VAS 6550/2- in a measuring container.

Fig 9: Identifying Pressure Tester VAS 6550 Connected To Fuel Supply Line Using Hose VAS 6550/1

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Make sure the drain is closed and the shut-off levers are open.

-- Operate the remote control -V.A.G 1348/3A-. Slowly close the shut-off lever -arrow- until the pressure tester shows 4 bar. From this point on do not move the position of the shut-off lever.

-- Empty the measuring container.

-- Repeat the fuel delivery test.

If the minimum delivery rate is now obtained:

-- Replace the fuel filter.

If the minimum delivery rate is again not obtained:

-- Remove the fuel delivery unit and check the fuel strainer for contamination.

Only when up to now no malfunction has been detected:

-- Replace the fuel delivery unit.

If delivery rate has been obtained, but malfunctions are still suspected in fuel supply (for example, intermittent loss of fuel supply):

-- Check the fuel pump current draw. Refer to CURRENT DRAW, CHECKING .