Fuel Pump, Checking Fuel Delivery Quantity
Fuel Pump, Checking Fuel Delivery Quantity
Special tools, testers and auxiliary items required
• Pry Lever - Rmv Outside Mirror (80 - 200)
• Fuel Inj. Pressure Gauge-CIS (V.A.G 1318)
• Vehicle diagnostic tester
• A measuring container that holds at least 3 liters and is fuel resistant (commercially available)
• Stop watch or a clock with a stop watch function
• Felt-tip pen
Procedure
- Observe test conditions. Refer to => [ Test Conditions ] Test Conditions.
- Remove the cover from the fuel filler tube.
- Install protective body covers. Refer to => [ Using Protective Body Covers ] Using Protective Body Covers.
R8 Coupe
- Remove the left engine compartment trim - 1 -.
R8 Spyder
- Remove the left engine compartment trim panel - 1 -.
Vehicles with 8-cylinder Engine
CAUTION!
Risk of injury from fuel.
• To reduce pressure in fuel system, lay a clean cloth around the connector and carefully loosen connector.
- Disconnect the fuel supply line - arrow -.
Vehicles with 10-cylinder Engine
CAUTION!
Risk of injury from fuel.
• To reduce residual pressure in fuel system, lay a clean cloth around the connector and carefully loosen connector.
- Remove fuel supply line - 1 -.
• Ignore - 2 -.
All Vehicles
- Connect (V.A.G 1318) with adapter (V.A.G 1318/11) and (V.A.G 1318/12) on the fuel line.
- Connect assisting hose - arrow - on pressure gauge and hold in a measuring container.
- Open the pressure gauge shut-off valve.
• The lever points in the direction of flow.
• A second technician is needed to operate the vehicle diagnosis tester for the following steps.
- Connect the vehicle diagnosis tester and turn on the ignition.
- Select the following menu entries:
• OBD
• 11 - Engine electronics
• Guided functions
• Output diagnostic test step 2 fuel pumps - electronic signal wire, J538
• The fuel pump starts slowly and will get faster within 5 seconds until it reaches full delivery (audibly).
- Generate pressure in the fuel system by slowly closing the shut-off valve on the pressure gauge while the fuel pump is running at full delivery.
• Specified value: 4 bar pressure.
- From this point on do not move position of shut-off tap.
- Empty measuring container.
CAUTION!
Follow the procedure exactly.
• Output diagnostic test - do not switch the next actuator. When the fuel injectors are being actuated, the output diagnostic test cannot be repeated without turning on the engine beforehand.
- Stop the output diagnostic test.
- Place the measuring container on a horizontal surface and hold the hose in the measuring container.
- Select the following menu entries on the vehicle diagnosis tester:
• Guided functions
• Output diagnostic test step 2 fuel pumps - electronic signal wire, J538
• The fuel pump starts slowly and will get faster within 5 seconds until it reaches full delivery (audibly).
- When the fuel pump has reach full delivery after approximately 5 seconds, start the stop watch and at the same time have the second technician draw a line on the measuring container with a felt-tip pen the height of the fuel.
- Press the stop watch after 15 seconds and have the second technician mark the fluid level with the felt-tip pen on the measuring container.
- Stop the output diagnostic test.
- Calculate the amount of fuel delivered from the two markings on the measuring container.
Vehicles with 8-cylinder Engine
- Compare quantity of fuel delivered with minimum delivery rate in diagram (cm3/15 s).
• Voltage at fuel pump with engine stopped and pump running is approximate. 2 volts less than battery voltage.
If minimum delivery quantity is not obtained, the following malfunctions may be present:
• Fuel lines pinched.
• Fuel filter clogged.
• Fuel pump faulty.
Vehicles with 10-cylinder Engine:
- Compare quantity of fuel delivered with minimum delivery rate in diagram (cm3/15 s).
• Voltage at fuel pump with engine stopped and pump running is approximate. 2 volts less than battery voltage.
If minimum delivery quantity is not obtained, the following malfunctions may be present:
• Fuel lines pinched.
• Fuel filter clogged.
• Fuel pump faulty.
Assembling
• Tightening specifications, refer to => [ Locking Flange Cover - Tightening
Specifications ] Fuel Delivery Unit and Suction Jet Pump Assembly Overview.
Assembly is in reverse order of removal, note the following:
- Mount the fuel line to the engine.