The throttle body is a key part of your car’s fuel injection system. It controls how much air goes into the engine to ensure it runs smoothly. But over time, carbon layers and other dirt can build up, meaning that you need a reliable throttle body service to get things working again. This can cause decreased performance, rough idling, or even stalling.
Fortunately, this publication explains what is done during a throttle body service, how you can properly clean the throttle body, the signs your car needs throttle body service, the benefits of a regular throttle body service, and many more. With this information, you’ll be able to keep your engine running at its best and extend the lifespan of your car.
What is a throttle body service?
Throttle body service is the procedure of inspecting, cleaning, and maintaining the throttle body, a crucial component of the fuel injection system in modern internal combustion engines. Since the throttle controls airflow, any gunk or debris in the body can reduce power and acceleration.
So, cleaning or servicing the throttle body should enable the engine to operate smoothly and cleaner.
The majority of people prefer cleaning the throttle body in their own workshop. But there are products specifically made for this job, so visiting a professional or mechanic store is only necessary if you are unsure of what to do.
What is included in throttle body service?
Generally, during throttle body service, the throttle body is cleaned and any dirt/debris that can damage the vehicle’s speed and gas mileage are removed.
Typically, throttle body service includes the following steps:
Throttle body inspection
The first stage in throttle body service is to inspect the throttle body for indications of damage or wear. This means checking the throttle body for cracks, leaks, and other problems that could affect how it works.
Removing the throttle body from the engine
The next stage is to remove the throttle body from the engine. This entails removing any electrical cables, hoses, or other components from the throttle body.
Cleaning the throttle body
Once the throttle body has been removed from the engine, you should use a solution made for only cleaning the throttle body to clean it. I do recommend the CRC 05078 Throttle Body Cleaner because it is what works during any routine throttle body service.
This cleaner easily gets rid of any carbon, grease, or other dirt that has built up on the throttle body.
Usually, a spray can or a brush is used to apply the cleaning solution, and the throttle body is scrubbed carefully to get rid of all the built-up deposits.
If I had to make a different recommendation, that would be the WD-40 Specialist Carb/Throttle Body & Parts Cleaner. It does the job just as well, and like me, 90% of the thousand buyers love it.
Check the throttle plate
The throttle plate is a part of the throttle body that controls how much air goes into the engine. During the throttle body service, you should check the throttle plate for signs of wear or damage and also clean it properly to ensure it functions well.
Reassemble the throttle body
After you must have cleaned the throttle body, it is important to reassemble it together and connect it to the engine. This entails reattaching any electrical connections, hoses, or other components that were removed during the removal procedure.
Examine the throttle body
After reassembling the throttle body, it is examined to verify that it is working properly.
This involves starting the engine and checking for any indications of delay or stopping, as well as verifying the idle speed to ensure it is within the manufacturer’s specs.
How to do throttle body service
This guide is basically how to clean a throttle body. So, whether you’re a professional or an average car owner who loves taking on projects without experience, this is for you.
The most common types of car maintenance are cleaning the fuel injectors and the throttle body. Cleaning the fuel injector is typically best left to professionals though, but you can easily clean the throttle body using basic tools and specialized cleaning sprays.
Below are the steps to clean or do throttle body service:
1. Park your car in a good location
Park your car in a level and well-illuminated area outside. It is not recommended to perform this task indoors due to the volatility of throttle-body cleaners.
Park your car in a location with ample space around each side of the engine compartment.
You can find the throttle body under the hood in the engine compartment. Without further ado, here are some tips to assist you in locating it:
- The throttle body is positioned between the air cleaner and the engine’s intake manifold.
- Most throttle bodies are made of aluminum.
- A linkage or flexible cable connects the throttle body to the gas pedal of your vehicle, allowing the throttle shaft to move when the gas pedal is depressed. (If you have trouble finding the throttle body, ask someone to press the accelerator with the engine off so that you can observe the throttle shaft’s movement.)
Locate your vehicle’s throttle body and check its connection to the air-intake tubes. If it’s attached with Torx-head screws, you’ll need Torx bits or screwdrivers to unscrew them. However, if it has a flat-blade or Phillips-head screw, a screwdriver should do the trick.
2. Tread gently
Take note of the electrical wires that connect to the throttle body. Do not tamper with them, as you won’t need to disconnect any terminals for this project.
For your safety, it helps to follow all recommended precautions when working on your vehicle.
To be on the safe side, simply disconnect the ground terminal (negative) of the vehicle battery.
Take extra care with this project and avoid smoking while working. Make sure to wear the recommended skin and eye protection, as you’ll be using a flammable spray cleaner.
3. Gather your supplies
The important tools that you need to clean the throttle body are as follows;
- You will need screwdrivers, Torx bits, Torx screwdrivers, combination wrenches, or socket wrenches.
- Furthermore, include a toothbrush or a small, soft-bristled parts cleaning brush.
Some throttle bodies have special coatings that may be damaged by hard-bristle brushes, so it’s best to use a soft-bristled brush. Some auto parts stores also sell specific throttle-body cleaning brushes that you can use.
You also need a flashlight with you along with eye protection. Others include:
- Rubber gloves
- Paper towels
- Cotton swabs
- Household oil
4. Identify hoses connected to the throttle body
Identify and label the small hoses connected to the throttle body or air ducts that need to be removed for accessing the throttle body.
You can use masking tape to label each hose and coupling or use special labeling tape to keep track of which hose corresponds to which nozzle/coupling.
5. Remove the air duct
Carefully remove the air duct attached to the throttle body. Also, be very careful not to disconnect any electrical wires or terminals. The air duct is typically secured with a hose clamp, which can be loosened using a screwdriver, Torx-head wrench, Allen wrench, or other hand tool.
In some cases, the air duct may be pressed in place and can be removed with gentle twisting and pulling. Assuming both sides of the throttle body are connected to air ducts with hose clamps, you only need to remove one side to access the throttle body for cleaning.
Note: if you are not able to safely remove the air ducts and access the throttle body, cease all efforts and seek the assistance of a professional technician.
6. Let out enough air
Carefully remove only enough air ducting to expose the throttle body, being mindful not to cause any damage to any gaskets.
Throttle bodies come in various forms, including those with two throttle blades for the traction control system and even electronic throttle controls known as “drive by wire.” Regardless of the type, the throttle body will likely resemble the one illustrated once exposed.
7. Apply your throttle body cleaner
Put on rubber gloves and protective eyewear if not already done so. Once the throttle body is accessible, spray the throttle-body cleaner into the air duct and use brushes to carefully remove dirt, gum, and varnish buildup.
Exercise caution to avoid letting the thin, plastic spray nozzle or any other object fall into the throttle-body opening. Wipe away residue frequently using paper towels.
Repeat the cleaning process until all interior surfaces are thoroughly cleaned to the bare metal. Use a flashlight to monitor your progress.
8. Oil up the throttle shafts
Before reinstalling the throttle-body ducts, apply a small drop of general-purpose household oil to the throttle shafts where they enter the throttle body. Only a small amount is necessary to keep the throttle blades rotating smoothly.
Use more paper towels to clean up any excess residue and fluid that may have spilled onto the engine or surrounding components.
9. Reinstall the throttle body ducts
Carefully reinstall the throttle-body ducts, tightening the hose clamps to the same level of tightness as before removal. This can be achieved by matching the force used to loosen the fastener during removal.
10. Reconnect your vehicle battery
After reattaching all components and removing any tools and materials from under the hood, reconnect the battery and start the engine.
You may experience an initial stumble or rough idle as the cleaner fluid and residue that may have entered the intake manifold are burned off.
Additionally, the engine control computer may need to “relearn” some parameters after a battery disconnection, which is normal.
11. Idle your engine for a while
Allow the engine to idle for a couple of minutes. Then, take your vehicle for a test drive. The improvement in drivability and performance may vary based on the amount of dirt, gum, and varnish present in the throttle body, but this preventative maintenance effort is meant to enhance the long-term reliability of your vehicle.
Put away all tools and properly dispose of used paper towels and rubber gloves. Then, store the remaining throttle-body cleaner for future use.
How often should a throttle body be serviced?
On most cars, the throttle body should be serviced every 50,000 to 80,000 miles. You may need to clean the throttle body more frequently if you travel in dusty or filthy conditions. In such instances, the throttle body should be checked and cleaned every 20,000 to 30,000 miles. If you drive in high-traffic regions, you will have to clean the throttle body more frequently because the engine is exposed to more wear and tear.
There’s basically no specific time good enough for throttle body service. Even YourMechanic experts suggest cleaning it every 75,000 miles.
In newer cars with electronic throttle controls, you can choose to clean the throttle body less often because it is less likely to get clogged with dirt. Also, electronic throttle control systems can adjust themselves and fix the problem of debris building up in the throttle body. Even with electronic throttle control, having the throttle body checked and cleaned every 50,000 to 80,000 miles is a good idea to guarantee correct operation.
Cleaning the throttle body is a straightforward procedure that entails removing the component, washing it with a specialty cleanser, and replacing it. During the cleansing process, examine the throttle body for indications of wear or damage, such as cracks or leakage, and replace any damaged components.
Signs your car needs a throttle body service
The throttle body is an essential component of the air intake system in modern cars, controlling the quantity of air that moves into the engine, which then burns the fuel in the cylinders. Also, allowing the proper quantity of air to penetrate is critical at all times for the engine to operate at peak performance.
When the throttle body is dirty, malfunctioning, or clogged, it prevents the passage of air into the engine, causing efficiency problems and sending unburned fuel through the exhaust system.
Here are seven signs of a faulty or malfunctioning throttle body to help you spot the problem before it’s too late.
Lack of power
When the throttle body doesn’t work right, either too much or too little air gets into the mixture. This causes the vehicle to lose power and not move as it should. When you push the accelerator, it should ideally enable more air to burn the extra fuel flowing in, but if it’s bad, there won’t be enough air and there will be no power surge.
Acceleration problems
Because of this dearth of power, the car’s acceleration will undoubtedly be problematic.
The vehicle will either have irregular acceleration or will not accelerate after a certain point, both of which will affect not only the power and efficiency but also the engine’s life.
Low or high idling
Low or high idling is one of the telltale signs that the throttle body is malfunctioning.
This includes the engine halting after coming to a complete stop, having a very low idle after starting, or stopping when the accelerator button is quickly depressed.
The dirt gathered produces turbulent airflow in the system, resulting in a varying idle speed.
Buildup of dirt or grime
One of the most common causes of throttle body clogging is the buildup of debris/dirt and grime within the component, also known as coking.
This results in a rough surface, which disrupts the air-fuel movement and reduces the efficiency of your engine. Carbon deposits create an uneven surface inside the component, causing a comparable issue.
Inadequate mileage
A choking throttle body will drastically reduce a car’s fuel efficiency. The full tank-to-full tank technique is the best way to measure the mileage.
You fill up the tank, take note of the odometer numbers, reset one of the trip meters, and then drive a few hundred kilometers.
Fill the tank once more and record the overall quantity of fuel consumed. The distance divided by the quantity of fuel consumed will provide you with an accurate estimate of your car’s mileage. If the difference is greater than 15%, the throttle body is likely to be malfunctioning.
Electrical issues
Electrical wiring is like a nervous system for cars, which depends more and more on sensors and technology. If the electronic sensor in the throttle body is dirty, it will cause the air-to-fuel ratio to be changed more than it needs to be.
This could cause the car to go into a secondary power-reduced state until a repair person checks it out.
Engine check light
If there is a problem with the throttle body’s performance, the electronic throttle control will be notified. This causes the check motor light to turn on.
There are a variety of reasons why this warning appears, and a malfunctioning throttle body is just one of them. As a result, you should perform a physical inspection to see if dirt has accumulated around the component.
Benefits of a regular throttle body service
The benefits of constantly servicing the throttle body service are listed below as follows;
Optimal engine performance
One of the most important benefits of throttle body service is that it makes the engine run better. Over time, carbon buildup and other dirt can get into the throttle body and make it more difficult for air to get into the engine.
This can cause the horsepower and torque to significantly drop, making the car feel slow and unreliable. With a throttle body service, the part can be cleaned and the engine’s performance can be brought back to where it was.
Improved fuel efficiency
Another benefit of a regular throttle body service is that your car experiences improved fuel efficiency. Assuming the throttle body is dirty, it can make the car use more fuel and cost more to run.
By having a throttle body service, the part can be cleaned and the engine can run better, using less fuel and saving money on fuel.
It prevents other engine problems
Throttle body service can also help prevent other engine problems from developing. For instance, a dirty throttle body can make the engine run rough, stall, or even fail. If the throttle body isn’t working right, these problems can happen.
This can also lead to bigger engine problems in the future. By regularly servicing the throttle body, you can avoid these problems and keep the engine running smoothly.
How much does a throttle body service cost?
The cost of a throttle body service can differ significantly based on several variables, including the vehicle’s make and model, the location of the repair facility, and the type of service being done.
On average, a simple throttle body cleaning procedure can cost anywhere from $200 to $300. Cleaning the throttle body and throttle plate, as well as examining the associated components for wear and damage, is normal. If any components need to be changed, the cost of the repair can skyrocket. For example, based on the make and model of the vehicle, the cost of replacing the throttle body can vary from $400 to $620 or more.
Aside from the cost of the service itself, there may be extra costs for labor, taxation, and other fees. Some repair shops may also offer extra services, like a full diagnostic check of the engine or a software update, which could add to the cost of the work.
Final thoughts
With regular throttle body service and other routine maintenance, a car lasts longer and keeps running smoothly for many years to come. So, make sure your car runs smoothly and reliably as possible by having a trained mechanic service the throttle body at the intervals suggested by the car manufacturer.
Bernard is the lead driver and force behind his Big Dog Garage Race Team. He is the General Manager and Chief Mechanic of Jay Leno’s Garage. Bernard and his crew of seven are responsible for all repairs, restoration and fabrication of Jay’s incredible automobile and motorcycle collection.
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