Fuel Injector Leakage, Injection Quantity and Spray Pattern

Injection Quantity, Proper Seal And Spray Pattern Of Fuel Injectors, Checking

Special tools and equipment






- VAG1348/3-2
- VAG1348/3A
- VAG1594A
- VAG1602
- VAS5051 with VAG5051/1

or

- VAG1551 with VAG1551/3B

Test requirement:
- Fuel pressure OK, checking. System Pressure, Fuel Pressure Regulator and Holding Pressure

Test sequence
- Remove fuel rail including fuel injectors from intake manifold. Fuel lines remain connected.
- Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM. Wiring and Component Testing Using VAG1598/31 Test Box
- Bridge terminals 1 and 65 at test box using adapter cables from VAG1594A connector test kit (this step supplies Ground (GND) to one side of relay coil for Fuel Pump (FP) relay).

Checking proper seal
- Switch ignition on.

NOTE: After switching ignition on, Fuel Pump (FP) will run continuously, even with engine not running. This is true because: Fuel Pump (FP) relay is supplied with B+ via central electrics after ignition is switched on. Fuel Pump (FP) relay receives negative via the cable bridge in test box.

- Check proper seal of fuel injectors (visual inspection). With Fuel Pump (FP) running, only 1-2 drops per minute may drip out per injector.
- If fuel loss is greater, stop Fuel Pump (FP) from running (switch off ignition) and replace faulty fuel injector.

Checking injection quantity
- Insert fuel injector to be tested in a measuring glass from VAG1602 injection quantity test device.






- Connect one terminal of fuel injector to engine Ground (GND) using an adapter cable and an alligator clip from VAG1594A connector test kit.
- Connect the second terminal of fuel injector to B+ using VAG1348/3A remote control, VAG1348/3-2 adapter cable and assisting cable.
- Switch ignition on.
- Fuel Pump (FP) must run.
- Activate VAG1348/3A remote control for 30 seconds.
- Perform measurement on all fuel injectors.
- After all four fuel injectors have been activated, place measuring glasses on an even surface.
- Specified value for each fuel injector: 179 ± 14 ml
- If measured value of one or more fuel injectors is outside of specified range, switch Fuel Pump (FP) off (switch ignition off) and replace faulty fuel injector.

NOTE: Also check spray pattern when checking injection quantity. Spray pattern must be the same for all injectors

- Re-install fuel injectors together with fuel rail.