Relieve the fuel system pressure, then remove the cover from the pump located at the rear of the left valve cover. Disconnect the electrical connector from the pump and detach the fuel feed line from it. Carefully loosen the high-pressure fuel line fitting from the pump and fuel rails, discarding the high-pressure fuel tube as a new one must be installed during reassembly. Unscrew the pump mounting bolts gradually until they are loose, discarding the old bolts for new ones upon installation. Remove the pump and the roller tappet from its bore, checking for wear and replacing it if necessary. Take out the bolt and the pump mounting plate, ensuring the cam lobe that drives the pump is at Bottom Dead Center before installation; if not, turn the crankshaft with a wrench until it is. Lubricate the roller tappet and its bore with clean engine oil, then install the tappet. Lubricate the pump mounting plate seal and install it, followed by the pump 0-rings, also lubricated with clean engine oil. Using new bolts, install the pump, tightening them in the correct sequence and to the specified torque. Clean the high-pressure fuel line fittings on the fuel rails, apply a little clean engine oil to the threads, and install the new high-pressure fuel tube, tightening the fittings in the correct sequence and to the specified torque. Finally, connect the fuel feed line and electrical connector to the pump, and install the pump cover.
