Fuel Injectors, Checking Injection Quantity, Leaks and Spray Pattern
Fuel Injectors, Checking Injection Quantity, Leaks and Spray Pattern
Special tools, testers and auxiliary items required
• Remote control (VAG1348/3A)
• Connector test kit (V.A.G 1594 A)
• Test box (VAG1598/31)
• Injection quantity tester (VAG1602)
• Vehicle diagnostic, testing and information system ( VAS 5051)
• Adapter (VAS 5051/1)
Requirements
• Fuel pressure OK, checking. Refer to => [ Fuel Pressure Regulator, Checking System Pressure and Residual Pressure ] Testing and Inspection.
Work sequence
- Remove fuel rail including injectors installed from intake manifold. Refer to => [ Fuel Injectors ] Removal and Replacement. Fuel hoses remain connected.
- Connect test box (VAG1598/31) at wiring harness to ECM, do not connect to ECM. Refer to => [ Electrical Testing, with Test Box VAG 1598/31 ] Electrical Testing, With Test Box VAG 1598/31.
Leak test
- Jumper terminals 1 and 65 at test box using adapter cables from connector test kit (VAG1594A) (this step supplies Ground (GND) to one side of relay coil for Fuel Pump (FP) relay).
- Switch ignition on.
• After switching ignition on, FP will run continuously, even with engine not running. This is true because: FP relay is supplied with B+ via central electrics after ignition is switched on. FP relay receives ground (GND) via the jumper in test box.
• Fuel pump must run.
- Check proper seal of fuel injectors visually. With FP running, only 1-2 drops per minute may drip out per injector.
- If fuel loss is greater, stop FP from running (switch off ignition) and replace faulty fuel injector. Refer to => [ Fuel Injectors ] Removal and Replacement.
Checking injection quantity
- Insert fuel injector to be tested in a measuring glass from injection quantity test device (VAG1602).
- Connect one terminal of fuel injector to engine Ground (GND) using an adapter cable and an alligator clip from VAG 1594 A connector test kit.
- Connect second terminal of fuel injector to B+ using remote control (VAG 1348/3A), (VAG1348/3)-2 adapter cable and assisting cable.
- Jumper terminals 1 and 65 at test box with leads from adapter set (VAG 1594 A).
- Switch ignition on.
• Fuel pump must run.
- Activate remote control (VAG 1348/3A) for 30 seconds.
- Perform measurements on all fuel injectors.
- After all four fuel injectors have been activated, place measuring glasses on an even surface.
• Specification per injector: 135 ± 10 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. Refer to => [ Fuel Injectors ] Removal and Replacement.
- If measured values for all fuel injectors are outside specified range, check fuel pressure. Refer to => [ Fuel Pressure Regulator, Checking System Pressure and Residual Pressure ] Testing and Inspection.
• Also check spray pattern when checking injection quantity. Spray pattern must be the same for all injectors.
- Reinstall fuel injectors together with fuel rail => [ Install in reverse order, paying attention
to the following: ] Removal and Replacement.