Air Supply

Which parts control engine air supply?

Air supply to the internal combustion engine is essential. No air means no combustion. The control of the flow of air is one of the ways that the engine speed is controlled. An engine running at high speed requires more air supply than an engine that is idling.

The parts responsible for engine air supply are:

• Throttle body

• Idle control valve

• Air filter hoses

How do I choose the correct throttle body or idle control valve?

These parts are specific to the engine and are often updated based on fuel economy targets or emissions criteria. The best way to find the correct replacement parts is to obtain the original part number (OE) and use our website’s search function to find the correct part. Often the OE part number is noted on the part that you need to replace.

If you are not able to obtain the OE part number there are a few factors to note when there are parts listed as correct for your vehicle:

• The number of pins on the electrical connector

• The design of the electrical connector

• Engine code

• Vehicle manufacture date (this is not the date the vehicle was registered but the date it was made

• Engine number sequence (up to or after as specific number/letter

• VIN (chassis number) sequence (up to or after as specific number/letter

What brand of throttle body or idle control valve should I choose?

Air supply parts such as throttle bodies or idle control valves do not fail or require replacement very often. As a result there are not that many aftermarket makers of them so choice of brand is not always an option. These parts are precision engineered so quality levels are not something to worry about either. Choose any brand that is available and one that is within your budget.

How can I tell my throttle body or idle control valve needs replacing?

OBD code readers should state if there is a problem with the throttle body or idle control valve. If you do not have access to an OBD code reader we would recommend that you have a qualified mechanic inspect your vehicle to diagnose the fault you have.

Here are some symptoms of a faulty throttle body or idle control valve:

• Engine does not accelerate as it should

• The acceleration is uneven

• The engine idles too fast or too slow

• Poor fuel economy

• Check engine warning light is illuminated