Fuel System, Bleeding

Fuel System, Bleeding

Special tools, testers and auxiliary items required

• Pressure gauge (VAG1318)

• Adapter (VAG1318/21)

• Vehicle diagnostic, testing and information system ( VAS 5051)

• Adapter (VAS 5051/1)

• Test box (VAS5226)

Fuel system without return line

• The fuel system without return line is recognized by the sealing cap - 2 - at connection for return line on the fuel rail.





• To prevent damage to catalytic converter the fuel system without return line must be bled after repair work on fuel rail or on fuel lines. The vehicle must only be started after bleeding

• Observe the rules for cleanliness. Refer to => [ Clean Working Conditions ] Multiport Fuel Injection.

CAUTION!
Work on the fuel system must only be performed when engine is cold!

Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.

- Close shut-off valve on special tool (V.A.G. 1318/21) by turning in "-" direction up to stop.





- Unthread sealing cap from bleeder connection - 2 - and connect Adapter (VAG1318/21) instead.





- Connect Adapter (V.A.G. 1318/21) and (VAS5226) catch reservoir with assistance of pressure gauge (V.A.G. 1318).





CAUTION!
All connection areas must be secured!

- Open shut-off valve on special tool (V.A.G. 1318/21) by turning in "+" direction.





- Switch ignition on.

• Fuel pump starts up briefly

Fuel system is bled when fuel exits into catch reservoir (VAS5226) without bubbles.

- Switch ignition off.

If the fuel pump does not operate, or fuel flows out on catch reservoir (VAS5226) continuously with bubbles:

- Connect tester (VAS 5051) and select control module for engine electronics using "address word" 01. Ignition must be switched on.

- Initiate output DTM and activate Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80). Refer to => [ Output Diagnostic Test Mode ] Output Diagnostic Test Mode.

• Fuel pump must run during activation time.

Fuel system is bled when fuel exits into catch reservoir (VAS5226) without bubbles.

- End function "03 - output Diagnostic Test Mode (DTM)" by pressing arrow button.

CAUTION!
Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.

- Close shut-off valve on special tool (V.A.G. 1318/21) by turning in "-" direction up to stop.





- Remove Adapter (V.A.G. 1318/21) from bleeder connection.

- Thread on sealing cap to bleeder connection - 2 -.