How to clean the throttle body

The throttle body needs to be cleaned when the engine idles unevenly, the engine stalls on acceleration, or the Check Engine light comes on.

Today's fuel-injected vehicles depend on a fully functional and clean throttle body to supply the air/fuel mixture to each cylinder. The throttle body is essentially a carburetor on a fuel injected engine that regulates the flow of fuel and air into the fuel injection manifold. As soon as the mixture enters the manifold, it is sprayed into the inlet of each cylinder by nozzles. When road dirt, carbon and other materials enter the components that make up the throttle body, the vehicle's ability to burn fuel efficiently is reduced.

The throttle body has been a vital component ever since fuel injection systems became more popular than carburetors in the early 1980s. Since then, fuel injection systems have evolved into finely tuned, electronically controlled machines that have increased engine fuel efficiency by as much as 70% over the past three decades.

The throttle body has not changed much in design or function since the first mechanical fuel injection systems were used. One thing that remains important is keeping the throttle body clean. Consumers today use several methods to keep their fuel systems clean.

One method is to remove and physically clean the fuel injection system. This is quite rare, but there are many car owners who go to great lengths to ensure their fuel system is as efficient as possible. Typically, this is done when a car owner notices that their engines are running inefficiently, as opposed to preventative maintenance.

Another method involves the use of fuel additives designed to clean fuel injection systems. There are dozens of fuel additives from different manufacturers that claim to clean fuel injection systems, from the injection ports to the throttle body vanes themselves. However, one reality with any supplement is that if it helps one system, there is often a trade-off where it can negatively impact another. Most fuel additives are made from abrasive materials or "catalysts". The catalyst helps the fuel molecules break down into smaller molecules that are easier to burn, but can scratch cylinder walls and other metal components.

The third method uses Carb cleaners or other degreasers. The correct method for cleaning the throttle body is to remove it from the vehicle and clean it thoroughly with a special degreaser designed for fuel system components.

Most car manufacturers recommend removing and cleaning the throttle body approximately every 100,000 to 30,000 miles. However, it is recommended to clean the throttle body on the car every XNUMX miles. By performing this scheduled maintenance, you can increase engine life, improve fuel economy and vehicle performance, and reduce emissions.

For the purposes of this article, we'll focus on the recommended methods for cleaning the throttle body while it's still on your engine after 30,000 miles. For tips on removing and cleaning the throttle body, including removing this component from your vehicle's engine, and the correct methods to use to clean and rebuild the throttle body, see your vehicle's service manual.

Part 1 of 3: Understanding the Symptoms of a Dirty Throttle Body

A dirty throttle body usually restricts the air and fuel supply to the engine. This can lead to symptoms that may affect the overall performance of your vehicle. Some of the most common warning signs that you have a dirty throttle body that needs cleaning may include the following:

The car has trouble upshifting: believe it or not, a dirty fuel injection system usually affects gearshifts in the first place. Modern engines are very finely tuned and are often controlled by on-board sensors and computer systems. When the throttle body is dirty, it lowers the engine's rev range, causing the engine to stumble and delaying the time the car has to upshift.

Engine idling is uneven: A normally dirty throttle body will also affect engine idling. This is usually due to excess carbon deposits on the throttle vanes on the throttle body or on the body shell. The only way to remove this soot is to physically clean the throttle body.

Engine Stumbles on Acceleration: In most cases, when the throttle body is dirty or clogged with excess carbon, fuel flow and engine harmonics are negatively affected. As the engine accelerates, it is set to rev up at a rate that effectively transfers engine power to auxiliary systems such as the transmission and drive axles. When the throttle body is dirty, this harmonic tuning is rough and the engine stumbles as it goes through the powerband.

"Check Engine" light comes on: In some cases, a dirty fuel injector throttle body triggers several sensors in the fuel injection system. This will illuminate warning lights such as "Low Power" and/or "Check Engine". It also stores an OBD-II error code in the vehicles ECM which should be loaded by a professional mechanic with the correct scan diagnostic tools.

These are just some of the common warning signs that the throttle body is dirty and needs to be cleaned. In most cases, you can clean the throttle body while it is still installed on the vehicle. However, if your throttle body is 100% electronically controlled, you need to be very careful when trying to clean the internal throttle body vanes. Chokes with electronic control are carefully calibrated; and when people try to clean the vanes by hand, the throttle body vanes usually fail. It is recommended that a certified mechanic complete the throttle body cleaning if you have a fully electronic throttle body.

As stated above, in this article we will provide some tips on how to clean the throttle body while it is still installed on your vehicle. This is for a throttle body that is mechanically actuated by a throttle cable.

Throttle body electronic systems must be removed before cleaning. Please refer to your vehicle's service manual for the exact steps to troubleshoot some of these issues; but always rely on the advice of an experienced ASE certified mechanic to clean the electronically controlled throttle body.

Part 2 of 3: Car Throttle Cleaning

In order to clean the throttle body while it is still installed on your engine, you need to determine if the throttle body is manually operated with a throttle cable. On older vehicles, the throttle body of a fuel-injected engine is controlled by a throttle cable that is either attached to the accelerator pedal or electronic throttle control.

The reason you need to consider this fact in the first place is because the electronic throttles are calibrated with incredibly tight throttle clearance. When you manually clean the throttle body, you are cleaning the vanes themselves. This may cause the electronic choke to malfunction. It is recommended to remove the throttle body from the vehicle and clean it or have this service done by a professional mechanic.

Be sure to check in your owner's manual or service manual that your throttle body is operated by a hand cable before attempting to clean the part while in the vehicle. If it's electric, remove it for cleaning or have an ASE certified mechanic do this project for you.

Necessary materials

• 2 cans of throttle body cleaner
• Clean shop rag
• Socket wrench set
• Gloves
• Replaceable air filter
• Flat and Phillips screwdrivers

• Socket set and ratchet

• Attention: Wear gloves to protect your hands.

Step 1: Disconnect the battery cables. When you work under the hood of a car, you will be close to the electrical connections.

Always disconnect battery cables from battery terminals before removing any other components.

Step 2 Remove the air filter cover, mass air flow sensor and intake pipe.. Remove the clips securing the air filter housing to the base.

Remove the union or clamps securing the mass air flow sensor to the lower intake hose.

Step 3: Remove the air intake hose from the throttle body.. After the other air intake hoses are loose, you will need to remove the air intake hose connection from the throttle body.

Usually this connection is fixed with a clamp. Loosen the hose clamp until the intake hose slides off the outer edge of the throttle body.

Step 4: Remove the air intake housing from the vehicle.. Once all connections are loose, you will need to remove the entire air intake shroud from the engine bay.

Set it aside for now, but keep it handy as you will need to reinstall it after cleaning the throttle body.

Step 5: Replace the air filter. In most cases, problems caused by a dirty throttle body can also be related to a dirty air filter.

It is recommended to install a new air filter every time you clean the throttle body. This ensures that your engine will run at full efficiency once the cleaning job has been completed. Refer to your vehicle's service manual for recommended air filter replacement.

Step 6: Cleaning the Throttle Body. The process of cleaning the throttle body in a car is quite simple.

While each throttle body is unique to vehicle make and model, the steps to clean it are similar.

Spray the throttle body cleaner inside the throttle body inlet: Before you start cleaning the throttle body with a rag, you should completely spray the throttle body vanes and body with plenty of throttle body cleaner.

Let the cleaner soak in for a minute or two. Spray throttle body cleaner on a clean rag and clean the inside of the throttle body. Start by cleaning the inner case and wipe the entire surface with a cloth.

Open the throttle valves with the throttle control. Wipe the inside and outside of the throttle bodies thoroughly, but aggressively enough to remove carbon deposits.

Continue adding throttle body cleaner if the rag starts to dry out or excess carbon builds up.

Step 7: Inspect the edges of the throttle body for wear and deposits.. After cleaning the throttle body, inspect the inner throttle body and clean the edges.

In many cases, this is what causes the throttle body to perform poorly, but many do-it-yourself mechanics overlook this.

Also, inspect the edges of the throttle body vanes for pits, nicks, or damage. If it is damaged, consider replacing this part while you still have access to the blades.

Step 8: Inspect and clean the throttle control valve.. While you are working on the throttle body, it is a good idea to remove and inspect the throttle control valve.

To do this, refer to the service manual for exact instructions. Once the throttle control valve has been removed, clean the inside of the body the same way you cleaned the throttle body. Replace the throttle valve after cleaning.

Step 9: Reinstall the components in the reverse order of removal.. After cleaning the throttle control valve and throttle body, install everything and check the operation of the throttle body.

Installation is in reverse order of removal for your vehicle, but these guidelines should be followed. Connect the air intake hose to the throttle body and tighten it, then connect the mass air flow sensor. Install the air filter housing cover and connect the battery cables.

Part 3 of 3: Checking throttle operation after cleaning

Step 1: start the engine. There shouldn't be any problems starting the engine.

At first, white smoke may come out of the exhaust pipe. This is due to excess throttle cleaner inside the intake port.

Make sure the engine idling is smooth and constant. During cleaning, it may happen that the throttles fall out of position a little. If so, there is an adjusting screw on the throttle body that will adjust the idle manually.

Step 2: Drive the car. Make sure the engine rises up through the rev range when driving the vehicle.

If you are having problems shifting gears, check this feature of the car during a test drive. Drive the car for 10 to 15 miles and make sure you drive on the highway and set the cruise control to make sure this system is working properly.

If you've done all of these checks and still can't pinpoint the source of the problem, or if you need an extra team of professionals to help fix the problem, have one of AvtoTachki's local ASE certified mechanics clean the throttle body for you. .