Fuel Injectors, Checking Injection Quantity and Seal
Diagnostic Procedures
Fuel Injectors, Checking Injection Quantity and Seal
Special tools, testers and auxiliary items required
• Torque wrench (V.A.G 1331) (5 to 50 Nm)
• Remote control (V.A.G 1348/3A) with adapter cable ( V.A.G 1348/3-2)
• Test adapter kit (V.A.G 1594 A)
• Injection Rate Tester (VAG1602)
Test conditions
• Fuel pressure must be OK, check => [ Fuel Pressure Regulator and Residual Pressure, Checking ] Fuel Pressure Regulator and Residual Pressure, Checking, fuel pressure regulator and retaining pressure, checking.
• Ignition switched off.
Test Sequence
- Remove intake manifold upper part (along with both intake manifold side parts). Refer to Repair Information.
- Disconnect harness connectors of fuel injectors 1 to 12 ( (N30) to N33, N83 to N86, N299 to N302).
• Cylinder bank 1 with cylinders 1 through 6 is located at right in direction of travel.
• Cylinder bank 2 with cylinders 7 through 12 is located at left in direction of travel.
- Remove fuel rail completely along with fuel injectors (fuel lines remain connected), fuel rail with fuel injectors, disassembling and assembling. Refer to Repair Information.
- Connect test box to Engine Control Module (ECM) 2 (J623) wiring harness on connecting test box for wiring test, refer to Repair Information.
Checking for leaks.
Checking injection quantity.
Checking for Leaks
- Bridge sockets 1 + 65 of test box with respective adapter cables. Fuel Pump (FP) (G23) must run.
• This work step allows the fuel pump to run when the engine is not running.
- Switch ignition on.
- Check injectors for leaks (visual inspection). Only 1 to 2 drops per minute may emit from each valve when fuel pump is running.
- Disconnect connection between test box sockets.
- Switch ignition off.
If fuel loss is greater:
- Replace faulty fuel injector.
When installing fuel injector, observe the following:
• Replace O-rings on all injectors and lightly moisten with clean engine oil.
• Insert fuel injectors into fuel rail perpendicular and in correct position, and secure them with retaining clips.
• Position fuel rail with secured fuel injectors on intake manifold and apply uniform pressure to press it in.
• The connectors must audibly engage in the injectors when pushed on.
- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.
Injection Quantity, Checking
- Insert a fuel injector to be tested into a measuring tube of VAG 1602 tester for fuel injection quantity.
- Using adapter cables, connect one terminal of fuel injector to be checked to engine Ground (GND).
- Connect second fuel injector terminal with adapter cable to remote control (V.A.G. 1348/3A with adapter cable (V.A.G 1348/3-2)).
- Connect alligator clip of remote control to positive terminal in engine compartment.
- Bridge sockets 1 + 65 of test box with respective adapter cables. Fuel Pump (FP) (G23) must run.
• This work step allows the fuel pump to run when the engine is not running.
- Switch ignition on.
- Operate remote control for 30 seconds.
- Repeat check on other injectors. To do this use new measuring beakers.
- Disconnect connection between test box sockets.
- Switch ignition off.
- After all injectors have been activated, place measuring glasses on a horizontal surface and compare the injected quantity. Specification: 128 to 140 ml per injector
If the tested value of one or more fuel injectors is below or above the indicated specified value:
- Replace faulty fuel injector.
When installing fuel injector, observe the following:
• Replace O-rings on all injectors and lightly moisten with clean engine oil.
• Insert fuel injectors into fuel rail perpendicular and in correct position, and secure them with retaining clips.
• Position fuel rail with secured fuel injectors on intake manifold and apply uniform pressure to press it in.
• The connectors must audibly engage in the injectors when pushed on.
- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.