Fuel Injector Leak Testing and Delivery Quantity, Checking
CAUTION!
Fire hazard! Do not smoke, work near heaters or open flame, or have anything in the area that could ignite fuel.
- System pressure OK, Testing and Inspection
- Remove intake air duct between Mass Air Flow (MAF) sensor and sound dampener.
- Loosen ignition wires only as far as necessary to remove fuel rail, and lay to one side.
- Disconnect fuel injector harness connectors.
- Disconnect fuel rail from intake manifold.
- Disconnect vacuum hose from fuel pressure regulator.
- Lift (and afterward support) fuel rail (complete with fuel injectors) from intake manifold.
Checking fuel injector leakage
CAUTION!
Fire hazard! Do not smoke, work near heaters or open flame, or have anything in the area that could ignite fuel.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
- Visually inspect fuel injector for leaks (with fuel pump running).
- Maximum: Two drops per minute per fuel injector
If fuel loss exceeds 2 drops per minute:
- Switch ignition OFF and replace leaking fuel injector.
NOTE: Always replace O-rings!
Checking fuel injector delivery quantity
CAUTION!
Fire hazard! Do not smoke, work near heaters or open flame, or have anything in the area that could ignite fuel.
- Insert fuel injector to be tested into calibrated measuring container from 1602 fuel analyzer kit.
- Connect one terminal of each fuel injector being tested to engine Ground (GND) using jumper wire from connector test kit VW 1594.
- Connect remaining fuel injector terminal to B+ using remote control VAG 1348/3A, adapter wire VAG 1248/3-2 and jumper wire from connector test kit VW 1594.
- Use scan tool "Output Diagnostic Test Mode" function 03 to trigger fuel pump relay -J17-.
- Operate remote control VAG 1348/3A for 30 seconds.
CAUTION!
Fire Hazard Do NOT smoke or have anything in area that can ignite fuel.
- After each 30 second fuel injector fill, place measuring container on level surface (to facilitate accurate reading) and record fuel quantity delivered.
Specified value (each fuel injector): 85 - 110 ml (2.9 - 3.7 oz.)
If the measured quantity for one or more fuel injectors is under or over the specified value:
- Replace faulty fuel injector(s).
If the measured values for all of the fuel injectors (as a set) are under or over the specified values:
- Check system pressure Testing and Inspection
- Re-install fuel injectors in reverse order of removal.
- Replace O-rings on all fuel injectors and lightly coat with engine oil.
- Slide fuel injectors into correct position in fuel rail and secure with retaining clips.
- Install fuel rail (complete with fuel injectors) into intake manifold by pressing it evenly all around.