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Checking operation of fuel shut-off valve N109 > < Removing

A3 Mk2

Installing
Installing
  DANGER!
Pay attention to correct assignment as regards the version of the metering pump -V54-. Auxiliary heaters with no fuel shut-off valve -N109- are never to be fitted with a metering pump -V54- intended for the version with fuel shut-off valve -N109-.
  Note
t  Observe correct assignment to auxiliary heater. On vehicles with diesel engine, different versions of the metering pump -V54- must be fitted depending e.g. on the version of the auxiliary heater (with or without fuel shut-off valve -N109- → Chapter), → Electronic parts catalogue.
t  The installation of a fuel shut-off valve -N109- is currently only planned for vehicles with diesel engine (only installed on VW vehicles; introduction for Audi vehicles not yet finalised) → Electronic parts catalogue
t  Currently no auxiliary heater with a fuel shut-off valve -N109- is installed in Audi A3 vehicles during production (introduction not yet finalised). However it is possible that individual vehicles have been retro-fitted with an auxiliary heater with a fuel shut-off valve -N109-; therefore it is important to pay attention to the correct version.
t  Currently the metering pump -V54- for auxiliary heaters with fuel shut-off valve -N109- has a grey plastic jacket, and the pump for auxiliary heaters without fuel shut-off valve -N109- has a black jacket.
t  The fuel shut-off valve -N109- (in the auxiliary heater) prevents fuel from entering the combustion chamber after the auxiliary heater is switched off. To allow the pressure in the fuel pipe between the fuel shut-off valve -N109- and the metering pump -V54- to dissipate, the metering pump -V54- for auxiliary heaters with -N109- has a bypass bore.
t  A metering pump -V54- intended for auxiliary heaters with fuel shut-off valve -N109- (e.g. metering pump -V54- with part number 2K0 963,303 C), allows a small quantity of fuel to flow through (bypass) to prevent the build-up of pressure or vacuum in the fuel pipe. This metering pump -V54- model is therefore not to be fitted on auxiliary heaters with no fuel shut-off valve -N109-.
   
t  In cases of doubt as to whether the metering pump -V54--C- has a bypass or not, connect the vacuum hand pump -VAS 6213- for example to connection -A- of the metering pump -V54-. Then use the hand pump to generate a vacuum or pressure of approx. 0.8 bar. In the case of a metering pump -V54- with bypass (for auxiliary with fuel shut-off valve -N109-), the vacuum or pressure will be dissipated within one minute via the metering pump -V54- (connection -B- must be open when doing so).
t  In the case of a metering pump -V54--C- intended for auxiliary heaters with no fuel shut-off valve -N109-, any vacuum or pressure applied at connection -A- (e.g. using a vacuum hand pump -VAS 6213-) must not be dissipated via connection -B- (no internal leaks in metering pump -V54-).
Install in reverse order of removal; note the following:
  A82-10071
–  Renew clips -D- at fuel pipes and secure them using suitable pliers.
–  Take care not to twist fuel pipes.
–  Attach fuel pipes at locations provided.
  Note
t  Fit metering pump and corresponding fuel pipes such that they do not make contact with other components (noise).
t  Metering pump designs may differ depending on type of fuel (petrol or diesel) - different version for vehicles with diesel engine is gradually being introduced. → Electronic parts catalogue
t  At the start of production, metering pumps of type “DP 40” were fitted on vehicles with petrol and diesel engines. The “DP 30.4” model was subsequently introduced gradually for vehicles with a diesel engine. It is no longer permissible to use these two versions on vehicles with an auxiliary heater with fuel shut-off valve -N109- → Electronic parts catalogue.
t  For auxiliary heaters with fuel shut-off valve -N109-, only use version “DP 41” (introduction not yet finalised) → Electronic parts catalogue.
t  Currently no auxiliary heater with a fuel shut-off valve -N109- is installed in Audi A3 vehicles during production (introduction not yet finalised). However it is possible that individual vehicles have been retro-fitted with an auxiliary heater with a fuel shut-off valve -N109-; therefore it is important to pay attention to the correct version.
t  For auxiliary heaters without fuel shut-off valve -N109-, do not use version “DP 41” → Electronic parts catalogue.
t  The metering pump versions (types “DP 30.4” and “DP 41”) which are only intended for vehicles with a diesel engine and an auxiliary heater without or with fuel shut-off valve -N109-, are not to be installed in vehicles with a petrol engine → Electronic parts catalogue.
t  After removing and installing fuel system components, the auxiliary heater is to be switched on and operated at full load for at least 10 minutes to ensure complete bleeding of the fuel pipe.
  A82-0472

Checking operation of fuel shut-off valve N109 > < Removing