Fuel Injectors, Checking Injection Quantity and for Leaks
Fuel Injectors, Checking Injection Quantity and for Leaks
• Follow all safety precautions. Refer to => [ Safety Precautions ] Multiport Fuel Injection.
• Pay attention to the rules of cleanliness. Refer to => [ Clean Working Conditions ] Multiport Fuel Injection.
Special tools, testers and auxiliary items required
• Remote Control (V.A.G 1348/3A)
• Adapter Lead (V.A.G 1348/3-2)
• Injection Rate Tester (V.A.G 1602)
• Connector Test Set (V.A.G 1594 C)
• Test Instrument Adapter/DSO (5-pin) (VAS 5565)
Checking for Leaks:
• Fuel pressure must be OK, checking, refer to => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Testing and Inspection.
- Remove the fuel rail - 2 - with the injectors installed, refer to => [ Fuel Injectors ] Fuel Injectors and place it on a clean cloth.
Do not disconnect the battery and do not disconnect the fuel supply line from quick acting coupling or at the fuel rail.
• The harness connectors must be disconnected from the fuel injectors.
- Remove the rear bench seat.
- Remove the cover - 1 - from the fuel delivery unit. The arrow - 2 - points in the direction of travel.
- 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.
- 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 fuel delivery unit and cover.
- Connect the remote control (V.A.G 1348/3A) to the test instrument adapter/DSO (5-pin) (VAS 5565) and to battery positive (+).
- Operate the remote control (V.A.G 1348/3A).
• This step allows the fuel pump to run when the engine is not running.
- Check the injectors for leaks (visual inspection).
• Only 1 to 2 drops per minute may emit from each injector when the fuel pump is running.
If the fuel loss is greater:
- Disconnect the connection to the battery positive (+) and replace the leaking fuel injector. Refer to => [ Fuel Injectors ] Fuel Injectors.
• If the fuel injectors are replaced, erase the adaptation values and adapt the Engine Control Module (ECM) again. Refer to "Guided Functions" in the vehicle diagnostic tester.
• Always use new seals.
Injection Quantity, Checking:
• The fuel pressure must be OK, checking, refer to => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Testing and Inspection.
• The fuel rail is removed.
• The fuel injectors are installed in the rail and the fuel line is connected.
• The fuel pump runs (connected to the battery with adapter cables).
- Place a fuel injector to be tested into a graduated measuring glass in the injection rate tester (V.A.G 1602).
- Using adapter cables from the connector test set (V.A.G 1594 C) , connect one terminal of the fuel injector to be checked to engine Ground (GND).
- Connect a adapter cable to the remote control (V.A.G 1348/3 A) and to the second terminal of the fuel injector.
- Connect the adapter cable (V.A.G 1348/3-2) to the remote control (V.A.G 1348/3 A) and the alligator clip to B+.
- Operate the remote control (V.A.G 1348/3A) for 30 seconds.
- Repeat the check on the other injectors. Use new graduated measuring glasses for this.
- After all the fuel injectors have been activated, place the graduated measuring glasses on a level surface and compare the quantity of fuel.
• Specified value: 85 to 105 ml per injector
While checking the injection quantity, the spray pattern should also be checked. The spray pattern must be the same for all injectors.
If the measured value of one or more injectors is below or above the indicated specified value:
- Replace the faulty fuel injector. Refer to => [ Fuel Injectors ] Fuel Injectors.