How to Replace a Fuel Injector in a Mercury Cougar

The fuel injector in a Mercury Cougar 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.

Instructions

1

Determine which fuel injector your Mercury Cougar will need. This depends not only on the make and model, but also the engine size. Models made from 1967 to 1970 were equipped with 289 cubic inch (ci), 302ci, 351ci, 390ci, 427ci and 428ci engines. Models built from 1970 to 1973 used 351ci and 429ci engines.

2

Look at the next generations of the Mercury Cougar. Models made from 1974 to 1976 used a 351ci, 400ci or 460ci engine. Models built from 1977 to 1979 had 302ci, 351ci and 400ci engines. Engine options for 1980 to 1988 models include a 140ci, 255ci, 302ci, 2.3L or 3.8L engine.

3

Examine the most recent versions of the Mercury Cougar. Models made from 1989 to 1997 are equipped with a 3.8L, 4.6L or 5.0L engine. The last generation was made from 1999 and 2002 and came equipped with a 2.0L Zetec or 2.5L Duratec engine.

4

Relieve the fuel system pressure and disconnect the negative battery cable with a socket wrench. Remove the air intake resonators and unplug the electrical connections for the fuel injectors.

5

Disconnect the vacuum hose for the fuel pressure regulator and unlock the spring lock coupling for the fuel lines with a socket wrench so you can disconnect the fuel line.

6

Remove the retaining bolt from the fuel line bracket with a socket wrench and take out the fuel rail with the injectors still attached. Remove the fuel injectors and discard the old O-rings.

7

Apply a small amount of clean engine oil to the new O-rings. Install the fuel rail and use a torque wrench to tighten the mounting bolts to between 71 and 106 inch pounds. Complete the installation by reversing the removal procedure.