Fuel Injectors Injection Quantity/Seal/Spray Pattern, Checking

Injection Quantity, Proper Seal and Spray Pattern of Fuel Injectors, Checking






Test requirement
- Fuel pressure OK, checking Testing and Inspection

Test sequence
- Remove fuel distributor including fuel injectors from intake manifold. Fuel lines remain connected.
- Connect VAG 1598/31 test box at wiring harness to ECM, do not connect ECM.
- Bridge terminals 1 and 65 at test box using adapter cables from VAG 1594A connector test kit (this step supplies Ground to one side of relay coil of Fuel Pump - FP - relay).

Checking for proper seal
- Turn 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 Ground connection is via the cable bridge in test box.


- Check to make sure fuel injectors are not leaking (visual check). 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 (End Output DTM) and replace malfunctioning fuel injector.

Checking injection quantity
- Insert fuel injector to be tested in a measuring glass from VAG 1602 injection quantity test device.







- Connect one terminal of fuel injector to engine Ground using an adapter cable and an alligator clip from VAG 1594A connector test kit.
- Connect the second terminal of fuel injector to B+ using VAG 1348/3A remote control, VAG 1348/3 - 2 adapter cable and assisting cable.
- Switch ignition on.
- Fuel Pump (FP) must run
- Activate VAG 1348/3A 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: 145 ± 12 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 malfunctioning fuel injector.


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


- Remove fuel injectors together with fuel distributor.