Fuel Pump Checking, Engine Code BPR (Metal Fuel Tank)
Fuel Pump Checking, Engine Code BPR (Metal Fuel Tank)
Special tools, testers and auxiliary items required
• Fuel inj pressure gauge-cis (VAG 1318)
• Pressure gauge adapter (VAG 1318/1)
• Adapter (VAG 1318/11)
• Hose adapter (VAG 1318/16)
• Adapter (VAG 1318/17)
• Fuel line feed adapter (VAG 1318/23)
• Remote control (VAG 1348/3A)
• Connector test set (VAG 1594C)
• Vehicle diagnosis, testing and information system (VAS 5051B) or multi-meter (VAG 1715 )
• Measuring container
Test Prerequisites
• Fuse for fuel pump in fuse holder OK.
• Battery voltage at least 11.5 volts
• All electrical components such as for example, lights and rear window heater, must be switched off.
• For vehicles with a automatic transmission, selector lever must be in the "P" or "N" position.
=> [ Function and Voltage Supply, Checking ]
=> [ Delivery Quantity, Checking ]
=> [ Current Draw, Checking ]
=> [ Fuel Pump Check Valve, Checking ]
Function and Voltage Supply, Checking
- Switch on ignition.
• Fuel pump must briefly start up audibly.
• Fuel pump runs quietly.
- Switch off ignition.
If Fuel Pump Does Not Start Up
- Fold the rear seat bench forward.
- Remove the cover from the fuel delivery unit.
- Disconnect the 4 pin connector - 1 -.
- Connect the (VAG 1527B) using adapter cables from (VAG 1594C) to outer terminals of the connector.
- Switch ignition on.
• Light Emitting Diode (LED) must light up briefly.
If LED does not light up briefly:
- Locate and repair open circuit in wiring using wiring diagram.
If LED lights up briefly:
- Remove the flange.
- Reconnect the 4 pin connector.
- Check electrical wires between the flange and fuel pump for continuity.
If no open circuits are found:
- Fuel pump is faulty, replace the fuel delivery unit. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.
Delivery Quantity, Checking
- Remove the fuel filler cap from the fuel filler tube.
- Fold the rear seat bench forward.
- Remove the cover from the fuel delivery unit.
- Disconnect the 4 pin connector - 1 -.
- Connect the (VAG 1348/3A) with an adapter cable to the fuel pump terminal - 1 - and to battery positive (+). The illustration shows the plastic fuel tank.
- Connect terminals - 4 - of harness connector and fuel pump using an adapter cable from (VAG 1594C).
CAUTION!
Fuel system is under pressure!
• Wear protective goggles and protective clothing to prevent injuries and contact with skin.
• Before loosening the line connection, place a cloth around the connection point. Then release pressure by carefully loosening the connection.
- Disconnect the fuel supply line - 3 - and absorb the leaking fuel with a clean cloth.
• Press the securing ring to disengage the line.
- Connect the (VAG 1318) with (VAG 1318/23) and (VAG 1318/17) to the fuel supply line.
- Connect the (VAG 1318/16) to the (VAG 1318/11) on the (VAG 1318) and hold it in a measuring container.
- Open the shut off lever on the (VAG 1318). Lever will point in direction of flow - A -.
- Operate the (VAG 1348/3A). Slowly close the shut off lever, until the (VAG 1318)shows 3.5 bar. From this point on do not move position of the shut off lever.
- Empty the measuring container.
- Delivery rate of the fuel pump is dependent on battery voltage. Therefore, connect a multi-meter to the vehicle battery using adapter cables from (VAG 1594C).
- 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 stopped and pump running (approximately 2 volts less than battery voltage).
Example
During the test, a voltage of 12.0 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 500 cm3/30 s.
If the minimum delivery rate is not attained:
- Check the fuel pressure regulator. Refer to => [ Fuel Pressure Regulator and Residual Pressure Checking, Engine Code BPR ] Fuel Pressure Regulator and Residual Pressure Checking, Engine Code BPR.
Fuel pressure regulator OK:
- Check supply line to fuel tank for kinks.
Supply line OK:
- Check fuel delivery rate in front of fuel filter.
- Disconnect supply line - 1 - from fuel filter input. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.
- Connect the (VAG 1318) to (VAG 1318/17 ) as shown.
- Connect the (VAG 1318/1) to the (VAG 1318/11) on the (VAG 1318) and hold it in a measuring container.
- Connection to suction jet pump must be connected.
- Insert fuel delivery unit.
- Reestablish the current supply to fuel pump.
- Add some fuel again.
- Cover the flange opening (danger of spraying).
- Open the shut off lever on the (VAG 1318). Lever will point in direction of flow - A -.
- Operate the (VAG 1348/3A). Slowly close the shut off valve, until the (VAG 1318) shows 3.5 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 quantity of fuel delivered with specification.
*) Minimum delivery rate cm3/30 s
**) Voltage at fuel pump with engine stopped and pump running (approximately 2 volts less than battery voltage).
• The minimum delivery quantity before the fuel filter/pressure regulator is less, due to operation of the suction jet pump.
Example
During the test, a voltage of 12.0 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 415 cm3/30 s.
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 filter strainer for dirt.
Only when up to now no malfunction has been detected:
- Replace the fuel delivery unit.
Delivery rate has been obtained, but malfunctions are still suspected in the fuel supply, for example sporadic loss of fuel supply:
- Check the fuel pump current draw. Refer to => [ Current Draw, Checking ].
- Install the fuel pump. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.
Current Draw, Checking
- Fold the rear seat bench forward.
- Remove the cover from fuel delivery unit.
- Disconnect the 4 pin electrical connector - 1 -.
- Connect the current clamp from the (VAS 5051B) or the (VAG 1715) to the terminal 1 wire - arrow - on the 4 pin connector.
- Start the engine and let run at idle.
- Measure the current draw of fuel pump.
• Specified value: Max. 9 amps.
• If the malfunction in the fuel system is sporadic, the test can also be performed during a road test, but a second person is required.
If the current draw is exceeded:
- Fuel pump is faulty, replace the fuel delivery unit. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.
Fuel Pump Check Valve, Checking
- Fold the rear seat bench forward.
- Remove the cover from fuel delivery unit.
- Disconnect the 4 pin electrical connector - 1 -.
- Connect the (VAG 1348/3A) with an adapter cable to the fuel pump terminal - 1 - and to the battery positive (+). The illustration shows the plastic fuel tank.
- Connect terminals - 4 - of the harness connector and fuel pump using an adapter cable from (VAG 1594C).
- Disconnect the supply line - 1 - from the fuel filter input. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.
- Connect the (VAG 1318) to the (VAG 1318/17 ) as shown.
- Connect the (VAG 1318/1) to the (VAG 1318/11) on the (VAG 1318) and hold it in a measuring container.
- Connection to suction jet pump must be connected.
- Insert fuel delivery unit.
- Reestablish current supply to the fuel pump.
- Add some fuel again.
- Cover the flange opening (danger of spraying).
- Close the (VAG 1318) shut off lever (lever perpendicular to direction of flow, position - B -).
- Operate the (VAG 1348/3A) at short intervals, until a pressure of approximately 4 bar has built up.
DANGER!
Danger of spray when opening the shut off lever. Hold container in front of open connection on (VAG 1318).
- If pressure builds up too high, lower excess pressure by carefully opening the shut off lever.
- Observe the pressure drop on the (VAG 1318).
• After 30 minutes the pressure must not drop below a 3.2 bar decrease.
If the pressure drops further:
- Check line connections for leaks.
If no fault is detected in the wiring:
- Fuel pump is faulty, replace the fuel delivery unit. Refer to => [ Fuel Delivery Unit ] Removal and Replacement.