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tip of the day on Throttle Bodies

mcgyver ky

Well-Known Member
March 25, 2003
Reaction score
City, State
ky where all the mud is
Year, Model & Trim Level
91ford exporer eddiebauer
Cleaning Throttle Bodies

Disconnect all the hoses and unplug any sensor wiring connectors. Make a note of which hose goes where. A good thing to do to avoid confusing a hose connection or wiring connector is to put a piece of masking tape on the hose or connector, another on the hose neck or sensor, and mark each with the same letter.

Now, loosen any clamps and work the duct off the throttle body and air cleaner housing and set it aside. When all the wiring and hoses are disconnected, you should not try to start the engine. Even if it should happen start and run, it will throw all kinds of DTC's and turn the Check Engine light on. Then you'll have to clear all the codes and make extra work you
don't need. In addition, the computer may have to relearn some idle and drivability settings, which will leave you with a poorly running engine for a while until it learns all over again.

Now take a good look inside the throttle body with a flashlight. Move the throttle linkage and open the throttle plate so you can get a good look inside. You'll see a black coating of dirt, gum, varnish and oil on the throttle plate and throttle body throat. This is what disrupts and blocks the airflow when the throttle is only open slightly or closed.

One thing you have to watch out for is that some throttle body bores have a coating to help reduce this buildup. But even with the protective coatings protecting the throttle body bores they can be affected over time. There are a few ways to clean out the throttle body and plate. The easiest is with carburetor cleaner and a very soft bristled toothbrush.

There are three reasons why you have to be careful with choosing the type of solvent and how it's applied.

If there is a protective coating on the throttle body bore, which includes most Ford products, a hard brushing and a strong solvent will take it right off. Once it's off then you will need to clean it out more often. There will be a warning label on the Fords to let you know the throttle body is coated.
There may be a temperature or some other sensor sticking out in the throttle body area that hard brushing or a strong solvent could damage. Also it may destroy a sensor "O" ring or seal.
The shaft of the throttle plate where it goes through the throttle body is sealed to prevent unmetered air from entering the engine. This unmetered air will adversely affect the air/fuel mixture. Again, hard brushing and a strong solvent may damage these seals

Before you do anything you will want to start the car up and let it get to operating temperature so the dirt in the throttle body will come loose. I highly recommend eye protection be worn through this process. You'll be working with spray chemicals that can cause severe eye damage and there are people out there who love you.

Now, what can we use to clean the throttle body? Most carburetor and choke cleaners are pretty strong. The same is true of cleaners that are sprayed into the air intake for combustion chamber cleaning. They have to be strong in order to be able to clean things without mechanical means such as scrubbing with a brush. Sprays cannot clean all areas, particularly the back of the throttle plate. In addition it is almost impossible to see which areas have been cleaned and which haven't.

A safe solvent to use is a tune-up or injector cleaner mixed 4:1 or 5:1 with gasoline. What ever you don't use you can pour into the gas tank. If you can find Throttle Body Cleaner you can use that as well. Just hold onto that little straw to keep it from flying into your engine. If you can't get a good spraying angle, this is what I did. Cut the red straw in half and put a piece of small vacuum line between the halves. Stick one half of the straw into the can and use the other end to point the spray anywhere you need to while holding the can upright.

Let's start by cleaning the outside of the throttle plate and bore. Scrub it with your soft bristled toothbrush and get it good and clean. Next hold open the throttle plate by holding the linkage with a piece of wire. Now you can clean the backside of the throttle plate, the throttle body wall and some of the intake manifold. You just want to brake up this gunk for now. Be very careful working around any sensors and the throttle shaft seals. When you're done, clean the garbage out with solvent and clean rags.

To clean the Idle Speed Control Valve (ISCV), refer to the specific service manual for the correct procedure to remove it. When it is out clean the passages in the throttle body and in the ISCV itself. A pipe cleaner is good for getting inside those small passages and make sure they are free.

Now put everything back together and start her up. It probably won't start right up as it usually does, so don't get nervous. Ignore the white smoke pouring out of your tailpipe; it will go away once you let the car run for a few minutes and your done.