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Removing and installing fuel extraction pipe > < Removing and installing fuel extraction pipe

A3 Mk2

Extracting fuel for auxiliary heater from fuel tank
Extracting fuel for auxiliary heater from fuel tank
  Note
t  From start of production up to conversion in model year 2007, fuel for auxiliary heater was extracted from fuel tank near reservoir housing. On these vehicles, the fuel pump -G23- is not activated in auxiliary heating mode when the engine is off.
t  In model year 2007, fuel extraction will be converted gradually; fuel will be extracted from and not near reservoir housing of fuel tank. Observe correct adaption → Guided Fault Finding function of vehicle diagnostic, testing and information system VAS 5051 and assignment of auxiliary heater → Electronic parts catalogue.
t  On vehicles on which fuel is drawn in from the reservoir housing of the fuel delivery unit in the fuel tank (designated for auxiliary heaters with part number 1K0 815 005, index “XX”, from software number “0060” onwards), reservoir housing of fuel delivery unit is filled with fuel due to activation of fuel pump -G23- before, during and at end of auxiliary heating mode → Electronic parts catalogue.
Assignment of fuel extraction via fuel delivery unit cover
  Note
t  The following illustration shows the fuel delivery unit cover for vehicles with 2.0 ltr. FSI or TFSI engine and front-wheel drive; the layout may differ depending on the engine and model.
   
t  In the case of fuel delivery unit cover -A- (with an increase -D-) fuel extraction is via the connection -C- near fuel delivery unit reservoir housing.
t  In the case of fuel delivery unit cover -B-, fuel extraction is via the connection -C- from fuel delivery unit reservoir housing.
Fuel extraction next to reservoir housing of fuel delivery unit
  Note
The following illustration shows the layout for vehicles with 1.6 ltr. petrol engine and front-wheel drive; the layout may differ depending on the vehicle model.
  A82-10097
Fuel for auxiliary heater is drawn in from fuel tank via fuel extraction pipe -A-.
  Note
t  The fuel extraction pipe -A- is attached to the cover of the fuel delivery unit -C- with grommet -B-.
t  Fuel for auxiliary heater is extracted in area of fuel pump next to reservoir housing.
t  If the fuel extraction pipe has not been properly routed in the fuel tank,this can lead to operating problems of the auxiliary heater if the fuel tank is not completely full (fault message “No flame” or “Repeated flame interruption”).
t  The position of the fuel pipe -A- in the fuel tank ensures that the auxiliary heater can still be operated even if the fuel tank is more or less completely empty.
t  If the auxiliary heater functions properly when the fuel tank is completely full and problems are encountered if the tank is only partially full (fault message “No flame formation” or “Repeated flame interruption”), this is an indication of incorrect routing of the fuel extraction pipe -A-.
t  To stop any deposits on the bottom of the fuel tank being drawn in by the auxiliary heater metering pump, the fuel extraction pipe -A- does not reach right down to the bottom of the tank -D-.
t  To prevent all the fuel from being extracted from the fuel tank in auxiliary heating mode and to prevent the metering pump -V54- from drawing in air (fuel vapour), the auxiliary heater is no longer activated if the fuel gauge is in the “red zone”.
t  If the vehicle is unfavourably parked (e.g. in the entrance to an underground garage with the rear left of the vehicle at the lowest point) and the fuel tank is less than 15% full, fuel may no longer be conveyed.
Fuel extraction from reservoir housing of fuel delivery unit
  Note
t  The following illustration shows the fuel delivery unit cover for vehicles with 2.0 ltr. FSI or TFSI engine and front-wheel drive; the layout may differ depending on the engine and model.
t  If fuel pump -G23- is not activated on vehicles in which fuel extraction is performed from the reservoir housing in auxiliary heating mode, problems may occur when starting the engine and in heating operation, depending upon quantity of fuel in fuel tank (fuel level in reservoir housing drops too far and fuel may not be supplied) and “Loss of flame” fault is entered into the auxiliary heater control unit -J364-.
  A82-0467
Fuel for auxiliary heater is drawn in from reservoir housing of fuel delivery unit -D- via fuel extraction pipe -A-.
  Note
t  The fuel extraction pipe -A- is attached to the cover of the fuel delivery unit -C- with grommet -B-.
t  Fuel for auxiliary heater is drawn in from reservoir housing of fuel delivery unit -D-.
t  If the fuel extraction pipe has not been properly routed in the fuel tank, this can lead to operating problems of the auxiliary heater if the fuel tank is not completely full (fault message “No flame” or “Repeated flame interruption”).
t  The position of the fuel pipe -A- in the fuel delivery unit reservoir housing -D- ensures that the auxiliary heater can still be operated even if the fuel tank is more or less completely empty.
t  If the auxiliary heater functions properly when the fuel tank is completely full and problems are encountered if the tank is only partially full (fault message “No flame formation” or “Repeated flame interruption”), this is an indication of incorrect routing of the fuel extraction pipe -A-.
t  To prevent all the fuel from being extracted from the fuel tank in auxiliary heating mode and to prevent the metering pump -V54- from drawing in air (fuel vapour), the auxiliary heater is no longer activated if the fuel gauge of the control unit in dash panel insert -J285- is in the “red zone”.
  A82-10098

Removing and installing fuel extraction pipe > < Removing and installing fuel extraction pipe