Delivery Quantity
Fuel Pump, Checking
Special tools, testers and auxiliary items required
• Wrench (T10202)
• Fuel injection pressure gauge (VAG 1318)
• Pressure gauge adapter (VAG 1318/1)
• Adapter (VAG 1318/11)
• Hose adapter (VAG 1318/16)
• Adapter set (VAG 1318/17A)
• Fuel line feed adapter (VAG 1318/23)
• Torque wrench (40-200 Nm) (VAG 1332)
• Remote control (VAG 1348/3A)
• Connector test set (VAG 1594C)
• Multi-meter (VAG 1715)
• Test instrument adapter/DSO (5-pin) (VAS 5565)
• Voltage tester (VAG 1527B)
Delivery Quantity
• Voltage supply is OK.
• Fuel pressure regulator and residual pressure is OK, checking, refer to => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Testing and Inspection.
• Fuel filter is OK.
- Remove the fuel filler cap from the fuel filler tube.
- Open the cover of the relay and fuse panel in the engine compartment E-box.
- Remove fuse SB6 in position F6 on the fuse holder. Fuse assignment.
- Connect the (VAG 1348/3 A) with the ( VAG 1348/3-3) to the left terminal (in direction of vehicle travel) of the fuse socket F6 - arrow -.
- Using insulating tape, tape over the second contact of ( VAG 1348/3-3) to prevent a short circuit.
- Connect the alligator clip to the vehicle's battery positive terminal.
• Delivery rate of the fuel pump is measured at 4 bar. Therefore the fuel pressure must be checked before measuring the delivery rate.
CAUTION!
Fuel system is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before disconnecting the connection, wrap a cloth around the connection. Then release the pressure by carefully disconnecting the connection.
- Disconnect the fuel return line - 1 - from the fuel filter/fuel pressure regulator.
• Press in the securing ring to disengage the fuel line.
- Connect the (VAG 1318/17A) to the fuel filter/fuel pressure regulator and hold the other end of the (VAG 1318/17A) in a measuring container.
- Operate the (VAG 1348/3A) approximately 5 seconds to fill the fuel filter.
- Empty the measuring container.
- Delivery rate of fuel pump is dependent on voltage. Therefore connect the multi-meter to the battery.
- Operate the (VAG 1348/3A) for 30 seconds and measure battery voltage.
- Compare the quantity of fuel delivered with specification.
*) Minimum delivery rate cm3/30 s
**) Voltage at fuel pump with engine off and pump running (approximately 2 Volts less than battery voltage).
Example
During the test, a voltage of 12.5 volts is measured at the battery. Since the voltage at the pump is approximately 2 volts less than battery voltage, there is a minimum delivery rate of approximately 580 cm3/30 s.
If the minimum delivery rate is not attained:
- Check the fuel supply line to the filter for possible restrictions (kinks) or clogging.
If the fuel supply line is OK.
- Check the fuel delivery rate in front of the fuel filter.
CAUTION!
Fuel system is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before disconnecting the connection, wrap a cloth around the connection. Then release the pressure by carefully disconnecting the connection.
- Disconnect the fuel supply line - 1 - from the fuel filter input.
• Press in the securing ring to disengage the fuel line.
- Install the (VAG 1318) with the (VAG 1318/17A ) as shown.
- Connect the (VAG 1318/1) to the (VAG 1318/11 ) on the (VAG 1318) and hold the other end of the (VAG 1318/1) in a measuring container.
- Open the shut off lever on the (VAG 1318). Lever will point in the direction of flow - A -.
- Operate the (VAG 1348/3A). Slowly close the shut off lever, until the (VAG 1348/3A) shows 4 bar. From this point on do not move the position of the shut off lever.
- Empty the measuring container.
- Operate the (VAG 1348/3A) again for 30 seconds. Compare the delivery quantity with the value determined from the first measurement.
If the minimum delivery rate is now obtained:
- Replace the fuel filter.
If minimum delivery rate is again not obtained:
- Remove the fuel delivery unit and check the filter strainer for contamination.
Only when up to now no malfunction has been detected:
- Replace the fuel delivery unit. Refer to => [ Fuel Delivery Unit ] Fuel Delivery Unit.
- Reconnect all disconnected fuel lines.
- Bleed the fuel supply system. Refer to => [ Fuel System, Bleeding ] Service and Repair.