The Mazda6 has a fuel injector that mixes fuel with air. This technology almost completely replaced carburetors in the late 1980s and its programmable firmware allows the same hardware to be used with different fuels. A fuel injector is only a nozzle and a valve; it still requires a pump to inject the fuel into the engine.
Determine which fuel injector your Mazda6 will need. This depends not only on the make and model, but also the engine size. Models made from 2002 to 2007 can have a 1.8L, 2.0L, 2.3L, 3.0L or 2.0L diesel engine. Models after 2007 come equipped with a 1.8L, 2.0L, 2.5L, 3.7L or 2.0L diesel engine.
Disconnect the negative battery cable with a socket wrench and relieve the fuel system pressure. Unplug the fuel injector electrical connections and remove the fuel lines from the fuel rail.
Remove the fuel rail mounting bolts with a socket wrench and take out the fuel rail and injectors as an assembly. Place a flat head screwdriver between the injector cup and clip finger. Push the clip finger out and remove it from the cup notch. Use pliers to pull the clip parallel to the fuel injector groove and remove it from the fuel injector. Take out the fuel injector and discard the clip and old O-rings.
Coat the new O-rings with clean engine oil. Install the new fuel retainer clip so that the central area of the fuel injector and clip finger is aligned. Press the injector into the cup until the cup contacts the lower surface of the cup. Make sure the injector and clip are installed properly and the clip is hooked into the injector cup notch.
Replace the fuel rail bolts and tighten them to between 15 and 19 ft. lbs. with a socket wrench.
Install the remaining components in the reverse order of removal.