This is written for my 2003 1.2 16v but may possibly work for other models.
You will need:
10mm Socket on a ratchet
10mm inverted star socket
50-100mm ratchet extension
non inverted star key set
CarbCleaner (CC) or brake cleaner
Toothbrush
1. Remove the 3 x 10mm bolts securing the airbox to the engine.
2. Remove and discard the 3 x 'crimp clips' that secure the main intake to the TB (under the ECU), the breather from intake to rocker cover (about halfway down the main air intake) and from pre airbox intake behind the left headlight (looking at car from the front).
3. Remove airbox to reveal rocker cover and put to one side.
4. Unclip ECU plugs but do not pull as there is an earth strap attached and undo 4 x 10mm nuts (the earth strap is located under one of nuts and I also marked one of my ECU plugs to make sure they went on correctly during reassembly) to remove the ECU from its cradle.
5. To remove the TB you need an inverted star socket, I cant remember the proper measurement they use (measured in E something) but I know its 10mm, remove the 4 x inverted star bolts and unplug the single plug connector from its location on the TB.
Be sure to capture the orange 'O' ring.
6. The ECU cradle will now come off with the TB, now the TB is off take it indoors and find yourself an old chinese food tub or similar and spray CC into it till its about 3-4mm deep.
7. Remove the 2 x star screws holding the butterfly in the TB using the non inverted star keys and put into the tub of cc, make a note of which way the butterfly sits in the holder for reassembly, there are two lugs on it so it only comes out one way just remember where these sit when its closed.
8. You don't have to do this but I found it easier this way:
Remove the 6 x clips from the black housing on the TB, nothing will fall out except for a fairly big gear wheel so dont worry although there are some springy electrical connections so be careful not to bend these, once cover is off, rotate the gears so that the butterfly is wide open and hold the whole TB in a fashion so that your palm holds the gears in place to stop it rotating back and remove the butterfly with your fingers, if its stiff grab it with pliers, once removed soak it in the tub of cc.
9. Grab your toothbrush and dip in the tub and then scrub any hardened carbon from inside the TB, mine was pretty bad so spent a fair amount of time cleaning it up until it was shiny like new, make sure its 100% clean then put to one side and clean your butterfly and bolts.
10. When clean, spray cc from the can onto all parts incase there is leftover residue and let air dry, this takes about a minute to fully dry, then wipe with a clean soft rag.
11. Move the gears to rotate the holder and refit the butterfly the same way in which it came out, to make sure when you let go it should close and leave a little gap for the air to get through but you can also push it closed sealing it completely, fit the 2 x little star screws and your butterfly is in.
12. Grab the black casing and check there is no debris etc in it and that the rubber sealing gasket is in good nick and in place then refit using the 6 x clips, they are sprung so fit one side then just push up with your thumb to fit.
13. Check the mounting face on the engine to ensure its clear of debris and then refit the 'O' ring, ECU cradle and TB making sure that the black casing that houses the gear wheels is facing forwards towards the headlights, dont forget to reconnect the plug you took off!
14. Refit the 4 x 10mm nuts along with the ECU earth strap and tighten up to FT (Phucking Tight), then reconnect the ECU cables.
15. Refit Airbox and where you have cut the 'crimp clips' use either Jubilee clips or big cable ties, as there is no real pressure or movement in the airbox or its pipes I used cable ties and have never had a problem.
If your one of these people that likes to 'improve' their electrical connections using WD40 then don't, if you have to do it use the cc as it evaporates but leave it a minute so you dont blow yourself up.
It looks like a long job but it takes about 5 minutes to get the TB out, 15 mins to clean it properly and then 5 mins to reassemble it.
Job done, Simples.
EDIT: When I did mine and then refitted I had an idle issue which turned out to be the butterfly as I had mounted it backwards, once rightly in, I took it for a ten min drive to let the ECU see the 'change' and then adjust everything up and its been bang on ever since.
Whilst your airbox is off its worth grabbing your 10mm and taking the air filter out and giving it a good clean, I found leaves and allsorts in mine lol.
You will need:
10mm Socket on a ratchet
10mm inverted star socket
50-100mm ratchet extension
non inverted star key set
CarbCleaner (CC) or brake cleaner
Toothbrush
1. Remove the 3 x 10mm bolts securing the airbox to the engine.
2. Remove and discard the 3 x 'crimp clips' that secure the main intake to the TB (under the ECU), the breather from intake to rocker cover (about halfway down the main air intake) and from pre airbox intake behind the left headlight (looking at car from the front).
3. Remove airbox to reveal rocker cover and put to one side.
4. Unclip ECU plugs but do not pull as there is an earth strap attached and undo 4 x 10mm nuts (the earth strap is located under one of nuts and I also marked one of my ECU plugs to make sure they went on correctly during reassembly) to remove the ECU from its cradle.
5. To remove the TB you need an inverted star socket, I cant remember the proper measurement they use (measured in E something) but I know its 10mm, remove the 4 x inverted star bolts and unplug the single plug connector from its location on the TB.
Be sure to capture the orange 'O' ring.
6. The ECU cradle will now come off with the TB, now the TB is off take it indoors and find yourself an old chinese food tub or similar and spray CC into it till its about 3-4mm deep.
7. Remove the 2 x star screws holding the butterfly in the TB using the non inverted star keys and put into the tub of cc, make a note of which way the butterfly sits in the holder for reassembly, there are two lugs on it so it only comes out one way just remember where these sit when its closed.
8. You don't have to do this but I found it easier this way:
Remove the 6 x clips from the black housing on the TB, nothing will fall out except for a fairly big gear wheel so dont worry although there are some springy electrical connections so be careful not to bend these, once cover is off, rotate the gears so that the butterfly is wide open and hold the whole TB in a fashion so that your palm holds the gears in place to stop it rotating back and remove the butterfly with your fingers, if its stiff grab it with pliers, once removed soak it in the tub of cc.
9. Grab your toothbrush and dip in the tub and then scrub any hardened carbon from inside the TB, mine was pretty bad so spent a fair amount of time cleaning it up until it was shiny like new, make sure its 100% clean then put to one side and clean your butterfly and bolts.
10. When clean, spray cc from the can onto all parts incase there is leftover residue and let air dry, this takes about a minute to fully dry, then wipe with a clean soft rag.
11. Move the gears to rotate the holder and refit the butterfly the same way in which it came out, to make sure when you let go it should close and leave a little gap for the air to get through but you can also push it closed sealing it completely, fit the 2 x little star screws and your butterfly is in.
12. Grab the black casing and check there is no debris etc in it and that the rubber sealing gasket is in good nick and in place then refit using the 6 x clips, they are sprung so fit one side then just push up with your thumb to fit.
13. Check the mounting face on the engine to ensure its clear of debris and then refit the 'O' ring, ECU cradle and TB making sure that the black casing that houses the gear wheels is facing forwards towards the headlights, dont forget to reconnect the plug you took off!
14. Refit the 4 x 10mm nuts along with the ECU earth strap and tighten up to FT (Phucking Tight), then reconnect the ECU cables.
15. Refit Airbox and where you have cut the 'crimp clips' use either Jubilee clips or big cable ties, as there is no real pressure or movement in the airbox or its pipes I used cable ties and have never had a problem.
If your one of these people that likes to 'improve' their electrical connections using WD40 then don't, if you have to do it use the cc as it evaporates but leave it a minute so you dont blow yourself up.
It looks like a long job but it takes about 5 minutes to get the TB out, 15 mins to clean it properly and then 5 mins to reassemble it.
Job done, Simples.
EDIT: When I did mine and then refitted I had an idle issue which turned out to be the butterfly as I had mounted it backwards, once rightly in, I took it for a ten min drive to let the ECU see the 'change' and then adjust everything up and its been bang on ever since.
Whilst your airbox is off its worth grabbing your 10mm and taking the air filter out and giving it a good clean, I found leaves and allsorts in mine lol.
