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Home >> Volkswagen >> 2012 >> Touareg TDI Executive >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> Diesel Fuel Injection [CATA] >> 23 Diesel Fuel Injection >> Diesel Direct Injection System >> Overview - Fuel System Schematic
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Overview - Fuel System Schematic

WARNING:
CAUTION:

Follow the points below to avoid running the high pressure fuel pump dry and to start the engine quickly after replacing the components:

If fuel system components between the fuel tank and high pressure fuel pump are removed or replaced, perform a basic setting "Transfer Fuel Pump, Checking" to bleed the fuel system.

If the auxiliary fuel pump, the fuel line between the fuel tank and high pressure fuel pump or the fuel filter is removed or replaced, perform the basic setting "Initial Fueling" >>one time<< before starting the engine for the first time.

If the high pressure fuel pump was removed or replaced, perform a basic setting "channel 35" >>three times<< before starting the engine for the first time.

Fill the fuel tank after installing the high pressure pump. Refer to FUEL SYSTEM, BLEEDING AND FIRST TIME FILLING .

Fig 1: Identifying Fuel System Schematic Overview
GWWA23-10282Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
  1. Fuel Metering Valve -N290-
    • Do not open
  2. Fuel High Pressure Pump
  3. High Pressure Reservoir (Rail)
    • Cylinder bank 1
  4. Fuel Pressure Regulator Valve -N276-
  5. Fuel Pressure Sensor -G247-
  6. High Pressure Reservoir (Rail)
    • For cylinder bank 2
  7. Piezo Injectors
  8. Leak Lines (Fuel Return Lines)
    • Do not disassemble the fuel return lines. Replace them completely with the pressure retention valve.
    • Run the engine at idle for approximately two minutes after replacing to bleed the fuel system and then check the fuel return lines for leaks.
  9. Pressure Retaining Valve
    • The check valve always maintains a residual pressure (control quantity) of approximately 10 bar (145 psi) in the fuel return lines.
    • The Piezo injectors need this control quantity to function correctly.
    • The check valve can be replaced only with the complete fuel return lines.
    • The engine must run at idle for approximately two minutes after replacing to bleed the fuel system.
    • Checking. Refer to RESTRICTOR IN THE FUEL RETURN LINE, CHECKING .
  10. Fuel Tank
    • With Transfer Fuel Pump -G6-
  11. Fuel Filter
  12. Auxiliary Fuel Pump -V393-