BMW 13537628049 High-Pressure Rail

Fuel injectors are electrically controlled solenoid valves that deliver precisely metered and atomized fuel into the engine intake ports, receiving voltage from the DME main relay. The engine control module (ECM) manages injector opening by activating the ground circuit for the injector valve solenoids, varying the duration of injector opening to regulate the air/fuel ratio. To begin, switch the ignition OFF and remove the key, then take out the cabin microfilter housing and ignition coil cover. For a quick check of the injectors, run the engine and touch each injector with a screwdriver or stethoscope to feel a vibration or hear a buzzing, then switch the engine OFF. Disconnect the battery negative (-) cable, ensuring to read the battery disconnection cautions beforehand. While working above the engine, detach the oxygen sensor connectors and unclip the wiring harness from the holder, marking the connectors for reassembly. Unscrew the schraeder valve cap from the fuel rail and connect an air line adapter to the fitting, also unscrewing the fuel tank cap to release pressure. Using a brief burst of compressed air, blow fuel back into the fuel tank. Next, remove and detach the fuel line, disconnect the connector strip, remove fasteners, and take out the fuel rail. To remove individual injectors, pry the retaining clip from the injector and pull it from the rail. Installation is the reverse of removal, ensuring to fit new sealing O-rings and lightly lubricate them for ease of installation. Check that the injector electrical connections are correctly fitted and that the injectors are fully seated before installing the fuel rail mounting bolts, and replace wire ties. After reinstalling, check for fault codes and reset the ECM memory.

Tighten the fastener for the hold-down bracket and the fuel injector rail fasteners, followed by tightening the fuel line nut.

Label the position and remove high-pressure fuel lines by using the special tool to loosen the nut while holding the injector with a wrench.