Throttle body and carburettor cleaner: restoring the suck

A throttle body draws air into an engine and they get clogged over time. Learn how to clean a throttle body with CAR's guide.

Spraying throttle body cleaner onto a throttle body

by Chris Williams |
Updated on

The sucking, squeezing, and banging of a car's internal combustion engine needs attention in order to function properly. Neglected, the titillating procedure begins to fail. In regards to the sucking, the throttle body plays a vital role. It's responsible for regulating how much air is drawn into the engine.

As the miles rack up, residue builds up on the throttle body and can cause it to function less effectively. The process of cleaning it is straightforward as car maintenance stuff goes and can easily be done by you.

Below is a guide on all you need to know.

What does a throttle body look like?

A throttle body in a car engine bay
©Photo: Getty Images

You can see what a throttle body looks like in the image above. It sits between the intake manifold and the air filter and is made from aluminium. It is likely covered by an air duct that connects the air filter and throttle body.

As the fuel and air combust in the chambers, carbon deposits accumulate on the throttle body, which can have detrimental effects on how your car's engine runs.

Symptoms of a dirty throttle body include rough idling and engine running (including misfires) and stalling. These symptoms occur because the clogged or dirty throttle is unable to draw in the correct volume of air required and creates a bad fuel-air mix. The throttle body's idle sensor can also be affected and not work properly.

What does a throttle body cleaner do?

It's an apt name. Throttle body cleaner is an aerosol spray that you apply to a dirty throttle body and can be used alongside an old toothbrush or similar to remove dirt and grime.

Below are the best throttle body cleaners:

Very effective and great value, Holts' EGR and Carb Cleaner is our top recommendation. It can be used beyond cleaning a throttle body and carburettors and also for air intakes and exhaust gas recirculation (EGR) valves.

Also a very effective throttle body cleaner from Wynn's. Unless you've got an old classic car, it's unlikely you'll use it to clean carburettors, but if you do, it's excellent for that too.

These three products are all very similar and perform very well. The S.A.S Throttle Body Cleaner is worthy of a podium place and can be used in the same way as the Wynn's spray.

We know that many home mechanics are dedicated users of Sealey tools, and that is fair enough. Its throttle body cleaner is good too, and if it's a name you wish to stand by, this spray allows you to and won't let you down.

How to clean a throttle body

Gather together the tools you'll need first. These will be:

Screwdrivers (torx), sockets and pliers to remove the air duct - important note: if you are unable to remove the air duct, then leave throttle body cleaning to a professional.

Throttle body cleaner

An old toothbrush or similar for stubborn dirt

Paper towels to wipe away grime

Step by step:

1. Replace the duct and clamps, tightening to the same degree they were before.

2. Disconnect your car battery's negative terminal to prevent any risk of short-circuiting.

3. Locate the big air duct that connects the air filter and throttle body. Carefully remove it by loosening its clamps with a screwdriver or whatever tool you need, along with any other hoses that need to be in order to access the throttle body. You may not need to remove the duct fully, but removing the air duct might require some gentle wiggling. Labelling the hoses helps you remember where to reconnect them afterwards. Avoid disconnecting any obstructing wires unless you're sure about it.

4. Now, with access to the throttle body, spray the inside of the throttle body with cleaner. Be very careful not to let anything fall into the throttle body. Scrub any stubborn residue loose with the toothbrush and wipe away with paper towels. Continue until the metal is completely clean. When finished, make sure the throttle body is totally dry and the surrounding area if there has been any spillage.

5. Replace the duct and clamps, tightening to the same degree they were before.

6. Remove your tools before reconnecting the negative battery terminal.

7. Start the engine. Do not worry if there is initially some rough idling or white smoke from the exhaust. There may be some throttle body residue that needs to burn off; additionally, modern cars' electronic brains sometimes have to recalibrate after the battery has been disconnected.

8. Let the car idle for a couple of minutes and take it for a test drive if you wish. If the throttle body was very dirty, you may notice an improvement in performance and even economy. Ultimately, cleaning a throttle body is one task in the overall upkeep and longevity of your car's engine.

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