How to Perform Throttle Body Maintenanceby Skip Shelton
The throttle body controls the amount of air which can be drawn into the engine. When the gas pedal is depressed, a cable opens the throttle plate at the mouth of the throttle body. The further the gas pedal is pushed, the wider the plate opens. Full depression of the gas pedal results in the throttle plate being fully opened. This is commonly referred to as "wide open throttle." A well maintained throttle body does not restrict incoming air. Following maintenance of a dirty throttle body, the idle will be more smooth, and throttle response is improved.
Throttle Body Maintenance
Disconnect the engine shroud, if your vehicle is so equipped. Engine shrouds are held in place with bolts, clamps or hand screws. Set the engine shroud to the side.
Disconnect electrical connections and vacuum hoses from the air intake tube, if they exist. Disconnect the air intake tube from the air filter box and throttle body mouth. The throttle body mouth is located at the opposite end of the air intake tube from the air filter box. Most air intake tubes are connected with screw type ring clamps. Use a small screwdriver or socket to loosen the worm drive screw until the air intake tube can be loosen and removed from the connection point. Set the air intake tube aside.
Place your finger on the top of the throttle body plate and push it. The throttle plate will lift open, Use your other hand to hold the throttle plate open. Shine a flashlight into the throttle body. Inspect for deposits. Black carbon deposits will need to be removed. The metal color should be the same as the outer lip of the throttle body mouth. If your throttle body plate has a breathing hold in the plate, it will need to be cleaned as well, to ensure smooth idle.
Spray throttle body cleaner in the mouth of the throttle body, until the deposits are all wet. Loosen the deposits with a soft bristled brush, such as an old toothbrush. Wipe away any loosened debris with a soft towel. Repeat the cleaning process until the metal under the deposits are fully exposed. It is not necessary to clean the whole throttle body, just what you can reach from the mouth with a long toothbrush.
Clean the throttle body plate, the plate hole and the lip of the throttle body mouth. Remove any deposits from the surfaces. Push the toothbrush bristles into and out of the throttle body plate hole until it is free of deposits.
Spray the remainder of the can at various angles into the throttle body mouth to remove deposits out of reach of the brush.
Reinstall the air intake tube on the throttle body mouth and the air filter box. Replace the vacuum hoses and electrical connection removed from the air intake tube. Tighten the clamps on the air intake tube. Reinstall the engine shroud.
Start the engine. The engine will not engage immediately, due to throttle body cleaner being present in the intake. Until the fluid is evaporated or consumed by the engine, the engine will run rough. Your engine will likely not fully start on the first few attempts. Wait 10 seconds between each attempt to allow your starter motor to cool. Attempt until the engine engages.
Idle the engine until the engine runs smoothly. This may take three minutes or more. Once the engine is relatively smooth, you may increase the idle speed to 1/3 throttle to reduce the wait time.
Drive the vehicle moderately for approximately 2 miles or until the acceleration and throttle response is smooth.
- check Do not place objects into the throttle body mouth which can fall into the intake. Removal of the throttle body and retrieval of the object will be required to ensure engine damage does not occur.
- check On-boar computers may take up to 50 miles of driving before the improved combustion settings are learned. During this time you may see a steady increase in throttle response time and idle smoothness.
- check While the air intake box is being access, inspect the filter. Replace if dirty.
- close Do not use brake parts cleaner or carburetor cleaner in the throttle body. Many throttle bodies have coatings designed to reduce deposit build-up. These coatings will be damaged by harsh solvents.
Items you will need
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