The VW Passat fuel injector uses pressure to mix fuel with air. This method rendered carburetors almost entirely obsolete during the late 1980s and allows the same hardware to be used with different fuels due to the fuel injector's programmable firmware. A fuel injector consists only of a nozzle and a valve; it still requires a pump to inject the fuel into the engine.
Determine which fuel injector your VW Passat will need. This depends not only on the make and model, but also the engine size. Models made before 1982 are equipped with a 1.3L, 1.4L, 1.6L or 1.5L diesel engine. Models built from 1982 to 1987 may have a 1.3L, 1.5L, 1.6L, 1.8L, 1.9L, 2.0L and 2.2L gasoline engines in addition to 1.5L, 1.6L and 1.8L diesel engines. Engine choices for 1988 to 1993 models include 1.6L, 1.8L, 1.9L, 2.0L and 2.8L sizes.
Examine engines for recent models of the VW Passat. Models made from 1994 to 1997 have 1.6L, 1.8L, 2.0L, 2.8L and 2.9L gasoline engines and a 1.9L diesel engine. Models built from 1996 to 2000 also offer a 2.3L gasoline engine and 2.5L diesel engine. The 2.9L engine was replaced with a 4.0L engine for 2001 to 2004 models. Models built after 2005 may have a 1.4L, 1.6L, 1.8L, 2.0L, 3.2L and 3.6L engine. This model is also available with a 1.9L and 2.0L diesel engine.
Relieve the fuel system pressure and disconnect the negative cable to the battery with a socket wrench. Remove the engine appearance cover and engine under cover if present. Take off the air cleaner and its ducting.
Disconnect any electrical connectors and vacuum hoses that prevent you from accessing the fuel rail. Detach the fuel send and return lines from the fuel rail and detach the electrical connectors from the fuel injectors.
Remove the mounting bolts for the fuel rail with a socket wrench and lift the fuel rail out of the engine compartment with the fuel injectors still attached. Pull the fuel injectors out of the fuel rail and discard the old O-rings.
Install the new fuel injectors and O-rings by reversing the removal procedure. Use a torque wrench to tighten the fuel rail mounting bolts to 89 inch pounds.
Start the engine and check for fuel leaks.