How To Test The Fuel Injectors (1991-1996 4.0L Ford Explorer And Aerostar)

Important Precautions When Removing The Intake Manifold Plenum

If you've found a fuel injector under the intake manifold's plenum that needs replacement, keep in mind the following suggestions:

  • Take care that no foreign object, like a bolt, a nut, or any metal piece/part, falls into the open manifold port runners.
  • After removing the plenum, cover the open intake runners with clean rags (shop towels). These towels will keep things from falling into the open runners.
  • As you're removing bolts, nuts, etc., from the intake plenum, place them in a container and away from the engine compartment.

If anything falls into the open intake runners, without you knowing, and you start the engine, you're going to be in a big world of hurt!

The only way to remove what fell in, after you've put everything back together is to remove the cylinder head(s). So be alert and be careful.

Don't worry. The plenum can be removed without complications or unhappy endings by simply following some precautions.

One last thing, when you reinstall the plenum, use new gaskets. Install these gaskets without any sealant, like RTV silicone. Using a sealant like RTV silicone may cause vacuum leaks down the road, and you're back to square one (removing the plenum).

More 4.0L Ford Explorer (Aerostar) Tutorials

You can find a complete list of 4.0L Ford Explorer (Aerostar) tutorials in this index:

Here's a sample of the tutorials you'll find in the index:

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Ford Vehicles:

  • Aerostar 4.0L
    • 1990, 1991, 1992, 1993, 1994, 1995, 1996
  • Explorer 4.0L
    • 1991, 1992, 1993, 1994, 1995, 1996