Fuel Injectors, Checking Injection Quantity and for Leaks

Fuel Injectors, Checking Injection Quantity and for Leaks

• Observe safety precautions. Refer to => [ Safety Precautions ] Multiport Fuel Injection.

• Observe the rules for cleanliness. Refer to => [ Clean Working Conditions ] Multiport Fuel Injection.

Special tools, testers and auxiliary items required

• Remote control (VAG 1348/3A)

• Adapter cable (VAG 1348/3-2)

• Injection rate tester (VAG 1602)

• Connector test set (VAG 1594C)

Checking for Leaks

• Fuel pressure must be OK, checking. Refer to => [ Fuel Pressure Regulator and Residual Pressure Checking, Engine Code BPS ] .

- Remove the fuel rail - 2 - with 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 at the quick acting coupling or at the fuel rail.

• Harness connectors must be disconnected from the fuel injectors.

- Fold the rear seat bench forward.

- Remove the cover from fuel delivery unit.

- Disconnect the 4 pin connector from the fuel delivery unit.

- Using an adapter cable, connect terminal - 1 - of the fuel pump to the battery positive (+).





- Connect terminals - 4 - of the connector and fuel pump using an adapter cable from (VAG 1594C).

• 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 vehicle diagnosis, testing and information system "Guided Functions".

• Always use new seals.

Injection Quantity, Checking

• Fuel pressure must be OK, checking. Refer to => [ Fuel Pressure Regulator and Residual Pressure Checking, Engine Code BPS ] .

• Fuel rail is removed.

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

• Fuel pump runs (connected to battery with adapter cables)

- Place a fuel injector to be tested into a graduated measuring glass from (VAG 1602).

- Using the adapter cables from (VAG 1594C), connect one terminal of the injector to be checked to engine ground (GND).





- Connect the second terminal of the injector with the adapter cable to the (VAG 1348/3A) using (VAG 1348/3-2).

- Connect the alligator clip to the battery positive (+).

- Operate the (VAG 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 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. 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 injector. Refer to => [ Fuel Injectors ] Fuel Injectors.