Fuel Injector: Testing and Inspection

WARNING: Fire hazard! Do not smoke, work near heaters or open flame, or have anything in the area that could ignite fuel.

FUEL INJECTOR LEAKAGE

REQUIREMENTS
^ System fuel pressure OK.

PROCEDURE
- Remove intake air duct between Mass Air Flow (MAF) sensor and sound dampener.
- Disconnect and lay aside ignition cables to permit removal of fuel rail.
- Disconnect harness connectors from fuel injectors.

Fuel Rail Mounting:

- Disconnect fuel rail from intake manifold.
- Disconnect vacuum hose from fuel pressure regulator.
- Lift fuel rail with fuel injectors off intake manifold and support.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
- Visually check fuel injectors for leaks (with fuel pump running).
^ With fuel pump running, no more than 1 to 2 drops of fuel per minute may be discharged from each fuel injector.

If fuel leakage is greater:
- Switch ignition off and replace leaking fuel injector and seals.

FUEL INJECTION DELIVERY QUANTITY

Injector Spray Test:

- Insert fuel injector to be tested into calibrated measuring container from 1602 fuel analyzer kit.

Injector Test:

- Connect one terminal from fuel injector to be tested to GND using test harness and clip from VW 1594 connector test kit.
- Connect second terminal of fuel injector to B+ using remote control VAG 1348/3A, adapter harness VAG 1348/3-2 or equivalent, and a test harness.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
- Operate remote control VAG 1348/3A for 30 seconds.
- After each 30 second fuel injector fill, place measuring container on level surface (to facilitate accurate reading) and record fuel quantity delivered.
^ Specified quantity per fuel injector: 85-110 ml (2.9-3.7 oz.).

If the measured quantity of one or more of the fuel injectors is greater or less than the specified value:
- Replace faulty fuel injector(s).
To complete the test:
- Repeat test on fuel injectors in second bank of cylinders.

If measured values of all fuel injectors are greater or less than specified value:
- Check system pressure.
- Install fuel injectors in the reverse order of removal.
- Replace O-rings for all fuel injectors and moisten slightly with clean engine oil.
- Slide fuel injectors vertically and in correct positions into fuel rail and secure with retaining clips.
- Install fuel rail (complete with fuel injectors) into intake manifold by pressing it evenly all around.