Fuel Injection Volume Leakage & Spray Pattern of Injector Check

Fuel Injection Volume, Fuel Injector Leakage And Spray Pattern Of Injectors, Checking

WARNING!
Fire hazard! The fuel system is pressurized. Before loosening hose connections or opening the test connection (to measure fuel pressure), place a cloth around the connection. Then release pressure by carefully pulling off the hose or cap.

Test conditions
- Fuel pressure OK Testing and Inspection

To reach the fuel rail, the following steps must be performed on vehicles with manual transmission (without secondary air injection). On vehicles with automatic transmission (with secondary air injection) are minor differences in the work procedure.






- Unscrew bolts on air duct at points indicated (arrows) and remove air duct.

Several hoses must now be disconnected:
- Absolute cleanliness must be maintained.
- After completing test, use new hose clamps and make sure they are installed properly.






- Connect test box VAG 1598/31 to wiring harness for engine control unit. Do not connect to the engine control module itself. Refer to "Scan Tool Testing/Wiring And Component Check With VAG1598/31 Test Box" Testing and Inspection

WARNING!
Make sure test box is inside of passenger compartment.






1 - Detach Wastegate Bypass Regulator Valve -N75 from fuel rail. The hoses must remain connected.

2 - Disconnect harness connector from EVAP Canister Purge Regulator Valve -N80.

3 - Disconnect - harness connector from Recirculating valve for turbocharger -N249.

4 - Open hose clamps shown in the illustration and detach hoses from air recirculating valve.

5 - Open hose clamp on fuel pressure regulator and detach hose.

6 - Disconnect harness connectors from injectors on cylinder banks 1 and 2.

7 - Open hose clamp and detach hose (vacuum hose for applying vacuum to the mechanical air recirculating (Bypass) valves when required).

8 - Open hose - clamps shown in the illustration and detach hoses. (The hoses lead to the intake (suction) sides of the turbochargers for cylinder banks 1 and 2).

9 - Open hose clamp shown in the illustration and detach hose. (The hose supplies fuel vapor to the intake manifold).

10 - Briefly - open screw connection on fuel rail (supply hose) to release pressure. Use clean cloth to catch any fuel that leaks out. Then tighten screw connection again.

WARNING!
Fire hazard! The fuel system is pressurized. Be fore loosening hose connections or opening the test connection, place a cloth around the connection. Then release pressure by carefully pulling off the hose or cap.

11 - Unbolt fuel rail from intake manifold at the points indicated (see arrows)
- Tightening torque bolts: 10 Nm
- Lift fuel rail off intake manifold together with fuel injectors and support the fuel rail.

NOTE:
- After lifting off the fuel rail, check to make sure that the injectors are properly secured to the fuel rail.
- It is possible that some of the fuel injectors will become detached from the fuel rail and remain in the intake manifold when the fuel rail is removed. If this happens, install the fuel injectors back onto the fuel rail.