Audi Workshop Service and Repair Manuals

Removing and installing high-pressure pump Removing   Note t  The high-pressure fuel pump should only be removed and installed when the engine is cold. t  When installing the high-pressure fuel pump, it is essential to ensure that no dirt enters the fuel system. t  Use a cloth to catch escaping fuel. t  The O-ring must always be renewed. t  Always ensure that the high-pressure fuel pipes are free of tension when tightening the connections.   WARNING Fuel system operates under high pressure. Always dissipate fuel pressure prior to opening fuel system. For procedure, refer to → Chapter. –  Unplug electrical connector -1- on fuel pressure regulating valve -N276-.

–  Disconnect fuel supply line -2- at high-pressure pump. –  Loosen union nuts -3- and take out high-pressure pipe.   Note t  Counterhold connections on high-pressure pump and fuel rail with a spanner when loosening union nuts. t  Use a cloth to catch escaping fuel.

–  Unscrew securing bolts -4- evenly.

–  Pull high-pressure pump -3- and roller tappet -1- out of camshaft housing.   Caution When removing or installing the high-pressure pump, take hold of it only by the housing. If the piston spring assembly of the high-pressure pump comes loose, the high-pressure pump will leak and must be renewed. Installing   Note Renew O-ring for high-pressure pump. –  Check roller tappet for damage and renew if necessary. –  Lubricate roller tappet -1- with clean engine oil. –  Insert lubricated roller tappet -1- into camshaft housing.

–  Turn crankshaft in direction of engine rotation until roller tappet is positioned at lowest point. –  Renew connecting piece for high-pressure pipe at high-pressure pump. –  Insert a new, oiled O-ring -2- into groove on high-pressure pump -3-. –  Carefully insert high-pressure pump -3-. –  Press high-pressure pump down by hand as far as possible onto stop.

–  At the same time, tighten securing bolts -4- by hand. –  Then tighten securing bolts -4- alternately to 5 Nm (do not tilt high-pressure pump). –  Now tighten securing bolts -4- alternately to final torque. l  Tightening torque for securing bolts: refer to high-pressure pump - exploded view → Chapter –  Hand-tighten union nuts -3- on high-pressure pipe. Align so that parts are free of tension. –  Align high-pressure pipe so it is free of tension and tighten to specified torque. l  Tightening torque: refer to exploded view of high-pressure pump → Chapter.

–  Re-connect fuel supply line -1- to high-pressure pump (make sure it is securely fitted).   Note Note arrows between fuel supply line and high-pressure pump.

–  Re-attach electrical connector -1- for fuel pressure regulating valve -N276-.   Note Check fuel system for leaks.