DIY : How to clean your throttle body

Due to the Chinese New Year holidays, RNR has been busy eating, reconnecting with relatives that we meet once a year (or longer), gambling with cousins for the rights to light the highly illegal mega firecrackers, and more eating. So to get back into gear again after the festivities, I thought I'd start with a pretty simple but equally essential DIY - How to clean your throttle body.

Ever cruise along the highway and the minute you slowed down at at traffic stop your car stalls and dies off? Or have unusual idling speeds? Or have an unresponsive throttle? Apart from the possibility of a leaking vacuum hose (check for cracks, kinks or disconnected vacuum hoses), it's likely you have a clogged throttle body (TB). This TB cleaning DIY applies to any car that has a throttle body and some cars have more than 1 TB. If so then you'll have more work to do. Take note that some modern cars have computers that complicate things - so if you drive one of those new fandangled computer-controls-everything cars, don't try this DIY unless you own a diagnostic tool that can reset ECU fault-codes and such. Modern cars with these new computers can be extremely finicky and are quite frustrating to meddle without the proper tools.

Tools needed :
Socket wrench tools
Throttle body cleaner and some petrol
A clean terry towel and toothbrush
A little know-how around the engine bay to identify which is the throttle body. You wouldn't want to accidentally remove an alternator, because if you did you deserve an award!

Identify which is your throttle body and remove everything connected to it. In the example above, it's the throttle body of a Perodua Myvi / Toyota Passo / Daihatsu Sirion. Basically if it's connected to the TB, remove it. Then free up the TB gently off its sitting position. Don't knock it when removing, cleaning and installing the TB. Some throttle bodies have sensitive gears inside them and any misalignment will result in a check-engine light, meaning you'll need the appropriate diagnostic tool to clear the error and reset everything.

When removing the vacuum hoses, check the hoses for any wear and tear. If there are cracks, tears or peeling - change them. Take note of which hose goes to which inlet/outlet, it helps if you use a tape marker or something to match-up the hoses with the appropriate connector.

Take this opportunity to clean the inlet of the intake manifold. Don't be overly aggressive with the cleaner, just spray the throttle body cleaner onto a terry cloth and use the cloth to wipe the inlet. Spraying the throttle body cleaner directly at the manifold will just drip all the oil/dirt/sludge further in it. Starting the car later will be a major pain the you-know-where and you'll get a large puff of smoke from your exhaust too which is bad for the environment and your sinuses.

Using the toothbrush and petrol, clean off the oil, dirt, gunk and all that nasty stuff from all the nooks and crannies of your TB. Remember to be gentle with the TB! Don't rattle those gears otherwise you'll be yanking out your hair, trust me. I'm semi-bald for a reason.

Make sure you get to the both front and back parts of the butterfly valve. Any gunk stuck there might result in your throttle being stuck open or be unable to close completely. Which is bad.

Take this opportunity to change out any gaskets, rubber O-rings, and all those perishables. You should be able to get replacements easily from your friendly local spare-parts shop for no more than a few bucks each.

Reinstall your TB (gently!) in the opposite way you removed it. Screw whatever bolts back in, insert whatever hoses that was connected and ensure you plug in any plugs and switches that you pulled out. If you're not completely confident doing this, take a picture with your smart phone before and after. Then just refer to the pictures when reinstalling everything back.

Take note I did not ask you to use the TB cleaner directly on the TB or to spray it directly at the TB without removing it first. Depending on what cleaner you buy, some have pretty potent cleaning agents in them and some modern TBs already come coated from factory with a special slippery slick layer inside the TB to prevent anything from sticking to it. Spraying corrosive cleaners at it will remove this super duper nice layer so let's not be asshats and don't remove something awesome that's supposed to be there.

Finally once everything is in place - pray. Pray hard.

Then turn the key to start the car. Give the car a few moments to register the squeeky clean throttle body and once it settles down you're done!

Tools needed to clean the TB - $20
Money spent on buying an extra TB in-case you screw up - $550
Not needing to use the spare TB because you listened to Izso's advice and didn't mess up - Priceless

- Izso