Fuel Injectors, Checking Injection Quantity and For Leaks

Fuel Injectors, Checking Injection Quantity and for Leaks

Special tools, testers and auxiliary items required

• Remote control connection (V.A.G 1348/3A)

• Adapter cable (V.A.G 1348/3-2)

• Injector quantity testing device (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 => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Fuel Pressure Regulator and Residual Pressure, Checking.

- Remove fuel rail - 2 - with fuel injectors installed => [ Fuel Injectors ] Service and Repair and place it on a clean rag.





Do not disconnect battery and do not disconnect fuel supply line at quick acting coupling or at fuel rail.

• Harness connectors must be disconnected from fuel injectors.

- Remove seat bench.

- Unclip cover - 1 - from fuel delivery unit. Arrow - 2 - points in direction of travel.





• On vehicles with auxiliary heater, harness connector of Metering Pump (V54) must also be disconnected.

- Disconnect connector - 1 -.





- Place test instrument adapter/DSO (5-pin) (VAS 5565) on the connector and on the fuel delivery unit.





- Connect the remote control (V.A.G 1348/3A) to the test instrument adapter/DSO (5-pin) (VAS 5565 ) and to battery plus (+).

- Operate remote control (V.A.G 1348/3A).

• This work step allows the fuel pump to run when the engine is not running.

- Check injectors for leaks (visual inspection).

Only 1 to 2 drops per minute may emit from each valve when fuel pump is running.

If the fuel loss is greater:

- Disconnect connection to battery plus (+) and replace leaking fuel injector => [ Fuel Injectors ] Service and Repair.

Injection Quantity, Checking

• Fuel pressure must be OK, checking => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Fuel Pressure Regulator and Residual Pressure, Checking.

• Fuel rail removed.

• Fuel injectors installed in fuel rail and fuel line connected.

• Fuel Pump (FP) runs (connected to battery with adapter cables).

- Place a fuel injector to be tested into a graduated measuring glass of injection quantity test device (V.A.G 1602).

- Using adapter cables from connector test kit ( V.A.G 1594 C), connect one terminal of fuel injector to be checked to engine Ground (GND).





- Connect second terminal of fuel injector with adapter cable to remote control connection (V.A.G 1348/3 A) using adapter cable (V.A.G 1348/3-2).

- Connect alligator clip to B+.

- Operate remote control (V.A.G 1348/3A) for 30 seconds.

- Repeat check on the other injectors. Use new graduated measuring glasses for this.

- After all fuel injectors have been activated, place graduated measuring glasses on a level surface and compare quantity of injected fuel.

Specified value: 85 to 105 ml per valve

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 faulty fuel injector => [ Fuel Injectors ] Service and Repair.