Fuel Delivery Quantity, Checking
Fuel Delivery Quantity, Checking
Special tools, testers and auxiliary items required
• Trim Removal Wedge (3409)
• Remote Control (V.A.G 1348/3A)
• Hand Held Multi-Meter (V.A.G 1526 E)
• Test Instrument Adapter/DSO (5-pin) (VAS 5565)
• Pressure Tester (VAS 6550)
• Vehicle Diagnostic Tester
• Measuring Container, 3 Liter
• The fuel delivery rate is first checked inside the engine compartment with Guided Functions "Check Fuel Delivery Rate, Quick Test". Perform a 2nd measurement on the fuel delivery unit flange if the minimum delivery rate is not attained.
• If driving is still impaired with the fuel tank 1/4 full, then perform a fuel delivery test with the fuel tank only 1/4 full or with very little fuel in the fuel tank.
Checking the amount of fuel using a measuring container:
- Connect the vehicle diagnostic tester to the vehicle.
- Select the Guided Functions in the vehicle diagnostic tester.
- Perform vehicle identification.
- Select engine.
- Select check fuel delivery rate, quick test.
- Follow the instructions for the vehicle diagnostic tester.
Checking the fuel delivery rate at the flange:
Test Conditions
• Pull on the connector without pressing the release to make sure the connection is secure. Repeat the fuel pump functionality test if the connector was not connected correctly.
• The "Check fuel delivery rate, quick test" was performed, refer to the vehicle diagnostic tester.
• The remote control (V.A.G 1348/3A) and the test instrument adapter/DSO (5-pin) (VAS 5565) are connected to the fuel delivery unit.
• The battery charger is connected
• The fuel level inside the fuel tank is above reserve
Test Sequence
- Remove the rear seat bench.
Engine codes CBTA and CBUA
- Remove the cover - 1 - from the fuel delivery unit. The arrow - 2 - points in the direction of travel.
Engine code CDVB
- Remove the cover - 1 - with the fuel pump control module - 2 - from the fuel delivery unit.
Continuation for All
- Pull on the connector - 1 - without pressing the release to make sure the connection is secure. If the connector was not connected correctly, it could cause a fault.
- Disconnect the connector - 1 -.
- Check the contacts on the connector and on the fuel delivery unit for damage.
The fuel lines are under pressure.
Danger of personal injury to eyes and skin.
Wear protective eyewear and protective clothing in order to avoid injury and contact with the skin. Wrap a cloth around the connection before removing a fuel hose. Open the connection carefully and release the pressure.
- Disconnect the fuel line - arrow - and wipe up the leaking fuel with a clean cloth. Refer to => [ Coupling, Disconnecting ] Service and Repair.
- Connect the pressure tester (VAS 6550) with the hose (VAS 6550/2) to the flange. Hold the other hose (VAS 6550/1) in a measuring container.
- Make sure the drain is closed and the shut off levers are open.
- Operate the remote control (V.A.G 1348/3A) and slowly close the shut off lever - arrow - until 4 bar displays on the pressure tester. 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. Therefore, connect the hand held multi-meter (V.A.G 1526 E) to the wires - 1 and 5 - of the test instrument adapter/DSO (5-pin) (VAS 5565).
- Operate the remote control for 60 seconds while measuring the battery voltage.
- Compare the fuel delivery rate to the target value.
*) Minimum delivery rate cm3/60 s
**) Voltage on the fuel pump with engine running in idle 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 cm3/60 s.
If the specification is not obtained:
- Check the fuel lines for possible restrictions (kinks) or blockages.
- Remove the fuel delivery unit and check the filter screen for dirt.
- Check whether the hose connections - arrows - to the fuel delivery unit - 1 - are sealed.
If no fault was detected:
- Check the fuel pump current draw. Refer to => [ Current Draw, Checking ] Current Draw, Checking.
If no faults were found while checking the current draw:
- Replace the fuel delivery unit. Refer to => [ Fuel Delivery Unit/Fuel Level Sensor ] Fuel Delivery Unit/Fuel Level Sensor.
If the fuel delivery rate was reached, even though a fault in the fuel supply is still suspected (for example, intermittent loss of fuel supply):
- Check the fuel pump current draw. Refer to => [ Current Draw, Checking ] Current Draw, Checking.