Fuel Injector, Checking
Fuel Injector, Checking
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)
• Follow all safety precautions. Refer to => [ Safety Precautions ] Safety Precautions.
• Pay attention to the rules of cleanliness. Refer to => [ Clean Working Conditions ] Clean Working Conditions.
Checking for Leaks
• The fuel system must be OK. Checking.
The fuel lines are under pressure.
Danger of personal injury to eyes and skin.
Wear protective goggles 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.
- Remove the fuel rail - 2 - with the injectors installed. Refer to => [ Fuel Injectors ] Fuel Injectors and place the rail on a clean cloth.
Do not disconnect the battery and do not disconnect the fuel supply line from the quick acting coupling at the fuel rail.
• The harness connectors must be disconnected from the fuel injectors.
- Remove the rear seat bench.
- Unclip 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 leak from each injector when the fuel pump is running.
If the fuel loss is greater:
- Disconnect the connection from 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 system must be OK. Checking.
• The fuel rail is removed.
• The fuel injectors are installed in the fuel 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 from the injection rate tester (V.A.G 1602).
- Using an adapter cable from the connector test set (V.A.G 1594 C) , connect to one terminal to the fuel injector, to be checked and the other terminal to Ground (GND).
- Connect second terminal on the fuel injector with an adapter cable to the remote control (V.A.G 1348/3 A) using adapter lead (V.A.G 1348/3-2).
- Connect 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 fuel injectors have been checked, 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. Spray pattern must be the same for all fuel injectors.
If the measured value of one or more fuel injectors is below or above the indicated specified value:
- Replace the faulty fuel injector. Refer to => [ Fuel Injectors ] Fuel Injectors.