We specialise in engines and gearboxes for cars and light commercials, we are one of the largest suppliers of Throttle Body in the UK. Many people look for totally reconditioned parts however we supply new and used as well, all our Throttle Body parts are supplied with a 100% warranty.
What is a Throttle Body?
In fuel injected engines, the throttle body is the part of the air intake system that controls the amount of air flowing into the engine, in response to driver input. The throttle body is usually located between the air filter box and the intake manifold, and usually attached to, or near, the mass airflow sensor. The largest piece inside the throttle body is the throttle plate, which is a butterfly valve that regulates the airflow.On many cars, the accelerator pedal motion is communicated through the throttle cable, which activates the throttle linkages, which moves the throttle plate. In cars with electronic throttle control (also known as “drive-by-wire”), an electric motor controls the throttle linkages and the accelerator cable connects not to the throttle body but to a sensor.
The Engine Control Unit (ECU) determines the throttle opening. On some modern cars, the accelerator cable is replaced by a pedal position sensor, which sends the pedal position to the ECU. When the driver presses on the accelerator pedal, the throttle plate opens up, allowing more air into the intake manifold. Either a throttle position sensor or an airflow sensor measures this change and communicates with the ECU. The ECU then increases the amount of fuel being sent to the fuel injectors in order to maintain the desired air-fuel ratio. Throttle bodies may also contain valves and adjustments to control the minimum airflow during idle. Even in those units that are not “drive-by-wire” there may be a small electric motor that the ECU uses to modify the throttle opening.
Many cars have a single throttle body, however more than one may be used, chained together by linkages, to improve throttle response. At the extreme end, cars such as the BMW M1 and high performance motorcycles like the Suzuki Hayabusa have a separate throttle body for each cylinder. This is often referred to as “individual throttle bodies”, or ITBs.
A throttle body is somewhat analogous to the carburettor in a non-injected engine. Carburettors combine the functionality of the throttle body and the fuel injectors into one, that is, to modulate the amount of air flow, and to combine air and gas together. Cars with throttle body injection (called TBI by General Motors and CFI by Ford) locate the fuel injectors in the throttle body, thereby allowing an older engine to be converted from carburettor to fuel injection without significantly altering the engine design.
Cleaning Engine Throttle Bodies
Modern electronic fuel-injection systems are some of the most trouble-free systems in your vehicle. However, if your vehicle has accumulated more than 75,000 miles, there is some routine fuel-injection-system maintenance that should be considered. The two most common maintenance jobs are fuel-injector cleaning and throttle-body cleaning. Cleaning fuel injectors is generally not a do-it-yourself project, but you can clean the throttle body on your vehicle with common tools and specialized spray cleaners.
While throttle-body cleaning is good preventative maintenance, it should also help engine drivability. In fact, if you’ve noticed a rough idle, stumbling initial acceleration or even stalling – all when the engine is fully warmed up – a dirty throttle body could be the culprit. Once you look inside a throttle body, you will probably be surprised at the dirt, gum and varnish that have accumulated there over time.
Setup Park your vehicle outside in a well-lighted, level area. Because the throttle-body cleaners are volatile, we do not recommend doing this job indoors.
Locate the throttle body under the hood in the engine compartment. Here are some hints on what to look for:
- The throttle body is located between the air cleaner and the intake manifold of the engine.
- Most throttle bodies are made of aluminium.
- The throttle body is connected to the gas pedal of your vehicle with a linkage or flexible cable, which moves the throttle shaft when the gas pedal is depressed.
(If you’re having difficulty locating the throttle body, ask a helper to press the accelerator – with the engine off – so you can see the movement of the throttle shaft.) - Once you have located your vehicle’s throttle body, look at how it is attached to the air-intake tubes. Sometimes throttle bodies are attached with special fasteners called Torx-head screws. If so, you will need Torx bits or Torx screwdrivers to remove these fasteners. More commonly, a flat-blade or Phillips-head screwdriver should do the trick. There may be one or more electrical wires that connect to the throttle body. Do not disturb these; for purposes of this project, you should not need to disconnect any of these terminals.
While we always recommend that you follow all appropriate safety precautions for these DIY projects, this is even more important for this project. Do not smoke when you are working on your vehicle, wear all recommended skin and eye protection and generally be aware that you are dealing with a flammable spray cleaner.
