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3.2 V6 Throttle Body Clean - How To

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25K views 68 replies 28 participants last post by  godisadj00  
#1 ·
There's been a few posts about cleaning the throttle body recently, and as I'd been experiencing similar symptoms (unsteady idling, hesitancy, jerkiness) I thought I'd give it a shot.

I have to say, I'm really pleased with the result - the response and running is silky smooth now, just like when I first got it.

If anyone hasn't had this done .... DO IT! It certainly won't hurt, and almost certainly will make a world of difference to your car's running. Don't be frightened off either. I'm a complete noob and I found it was really quite easy.

To give something back to the forum I made a photo log of my experience to provide a step-by-step guide for everyone's benefit. I hope it's useful.

3.2 V6 Throttle Body Clean - How To

This procedure must be carried out on a cold engine, because the throttle body needs to reset itself once reassembled and a cold engine is a requirement for that to happen.

The whole thing takes around one to two hours to complete

What you will need:

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1. In order to remove the air hose you'll need to undo a spring hose clamp. A pair of channel lock pliers like in the photo will do it

2. The throttle body itself is attached by 4 hex bolts. I found that a 5mm hex bit on a long screwdriver (like the one that I bought especially) worked best because I couldn't access the very bottom bolt using an allen key, not even a long one

3. When re-assembling you should seal the O-ring gasket with a smear of Silicone Grease. I found that Maplins sell small tubes of it for about ÂŁ5 (Maplin product code RE90X)

4. To do the actual cleaning you will need a can of carb cleaner, such as the one I got from Halfords (product code 294918-0) for about ÂŁ5

5. A clean lint free cloth

6. Cotton buds

7. Plain white paper

8. Since you will need to disconnect the battery, make sure you have you radio code so you can re-activate it afterwards. The 4 digit code should be in your car handbook or other documentation that you received with it

Step 1 - Disconnect Battery

Unlock the car and open the boot - in the V6 the battery is in the boot, underneath the carpet with the toolset, the latter of which has a spanner that fits the nut on the negative terminal of the battery. Disconnect the negative terminal and tuck the disconnected wire away from the terminal.

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Place a towel across the latch of the boot so that it won't engage if you try to close the boot. Since the boot latch is battery operated, you won't be able to open the boot again to re-connect the battery so this will prevent that happening. Having said that, there is an escape mechanism that can be used to manually open the boot but it can be a bit stiff to operate.

Step 2 - Unclip The Air Hose At The Airbox Side

To get the best access to the 4 bolts holding the throttle body, you need to remove the air intake hose. Start at the end shown in the picture and either use the pliers to undo the clip and pull back the pipe, or if you prefer you can undo the two screws that attach it to the air box. If you do the latter, you'll need a short philips-head screwdriver so that you can access the bottom screw easily, and I would advise to cup you hand underneath the bottom screw so that it doesn't drop into the engine when undoing it.

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Step 3 - Unclip The Throttle Body Power Cable

Before undoing the other end of the air hose, unclip the power cable that attaches to the throttle body housing. You'll need to insert a small flat-head screwdriver and gently depress the catch while pulling the plug to remove it. You may be able to just do this by hand, as I did.

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Step 4 - Unclip The Air Hose At The Throttle Body Side

With the power cable un-plugged and tucked out of the way, use the pliers again to release the air hose clip and pull the hose back to reveal one side of the throttle body internals.

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(Extra points to those who note how clean it looks inside already... ok, I admit I forgot to take a photo of this so I took one after cleaning LOL)

Step 5 - Undo The 4 Hex Bolts

The two top bolts can easily be accessed, but the ones on the left and at the bottom are more tricky to get to, and can potentially drop into the engine bay unless you're really careful. Use the screwdriver with the 5mm hex bit to undo the bolts and while doing the bottom two use your free hand to guide the bolts out so you don't lose them in the engine bay. Once the bolts are fully undone pull them out and put to one side.

Step 6 - Remove The Throttle Body

Now remove the throttle body by giving it a slight twist, then gently pulling it towards you (it's not held on by anything now) and this will reveal the air intake chamber on the other side of the throttle body.

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If anything gets into this open hole it could cause a lot of problems, so me being paranoid I would advise to block the hole temporarily to be on the safe side. I used a scrunched up plastic carrier bag and gently inserted it a little into the hole

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Step 7 - Cleaning The Throttle Body

Now onto the business :)

As you can see, my throttle body was pretty gunked up

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It's very important to note that during the cleaning process you should keep the cleaning solution away from the electronics of the throttle body, or you may damage it. To that end, always keep the electronics parts at the top so that the cleaning solution naturally drains downwards and away from the components. In the photo below, the electronics are housed inside the black part of the throttle body.

Also note that the throttle butterfly (the round bit in the middle) is driven by a sensitive stepper motor, so do not use any force on the butterfly or try to open it as otherwise damage may result.

Holding the throttle body in one hand with the electronics side upwards, carefully spray the carb cleaner into and around the throttle butterfly. Wait for a few secs then gently use the clean cloth to wipe away the majority of the gunk. Now gently use the cotton buds to wipe around the circumference of the throttle butterfly.

Now take a clean piece of paper and tear off a small strip. You can then feed the paper through the gap around the top and bottom of the throttle butterfly to dislodge the gunk trapped where we can't get to. Be very careful not to get too close to the hinges of the throttle butterfly or the paper will become stuck in there! And make sure to only use the cut edge of the paper to do the actual cleaning as the torn edge will be ineffective and is likely to get stuck in there. With the gunk dislodged, use a cotton bud soaked in carb cleaner to wipe around the edge and clear it up.

Repeat this process for both sides of the throttle body, then repeat the above steps until you can't get any more gunk out.

Once you're satisfied it's all clean, and still holding the electronics upright, give a final spray around with carb cleaner, let it drain off then dry off with the cloth and cotton buds. Put the whole throttle body down with the electronics upright and leave it to dry off for a while.

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The finished result should look something like this

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Step 8 - Prepare For Refitting

Remove the inserted carrier bag from the hole and give the O-ring and mating surface a quick wipe around with a clean cloth to remove any muck that's accumulated so there is a clean surface to use. Then apply a smear of Silicone Grease to the O-ring in preparation for re-fitting of the throttle body.

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Step 9 - Refitting The Throttle Body

It's fairly tricky to re-attach the throttle body without making a mess of the Silicone Grease, so insert the top two throttle body bolts into the throttle body and use them as alignment assistants while you carefully bring the two mating surfaces together. Once the two top bolts are inserted into their holes on the other side just do them up a couple of turns to keep the body in place while you carefully insert the remaining two bolts at the bottom, then do these two up a couple of turns.

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Once all four bolts are in, work around each bolt in turn gradually tightening each one up so that the two mating surfaces are naturally drawn together. This keeps the alignment of the throttle body straight so that the Silicone Grease doesn't get displaced and can do its job.

Finally tighten all four bolts - but don't over do it!

Step 10 - Refit The Air Hose & Power Supply

Quite simply the reverse of the procedure to disassemble, use the pliers to re-attach the air-intake side air hose, making sure it is fully seated into its original position, then plug the power supply cable back in. Then re-fit the air box side of the air hose.

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Step 11 - Re-connect the battery

Once you're certain everything is back in place and done up correctly, re-connect the negative terminal of the battery.

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If, like me, you closed the boot then you won't be able to open it, so you' you'll need to open it using the plastic loop hidden in the centre tunnel:

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Step 12 - Throttle Body Alignment

The throttle body must be re-aligned. This will happen automatically - just insert the key into the ignition and turn it until the dash lights are on... but do NOT start the car. Leave the key in this position for 5 minutes. During this time you should hear some clicking going on in the engine bay. This is the throttle body alignment doing its stuff.

Step 13 - Radio Code

While you're waiting for the throttle body alignment to complete you may as well re-enable your radio by entering the code from your handbook. The unit will display SAFE on the front. You need to simultaneously hold down the RDS and SCAN buttons for a couple of seconds until the display changes to four zeros. Then you can use the radio station buttons from left to right to enter the four digit code - button one changes digit 1, button two changes digit 2 and so on. When you've entered your code simultaneously hold down the RDS and SCAN buttons to set the code.

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Step 14 - Set The Date & Time

The clock will also be reset to your car's dash pod manufacture date, so this is another job that can be done while waiting for the throttle body reset to take place.

On the dash, pull the left silver knob (under the rev counter) towards you until the Hours flash, then turn the knob to the right or left to increase or decrease the hours. To advance to minutes pull the knob again and set the minutes, again for year, month and so on.

Step 15 - Enjoy!

By this time the throttle body reset will have taken place. Remove the key from the ignition, re-insert and start the engine. Now drive off and have fun! (Oh, and make sure the bonnet is closed first!)
 
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#27 ·
I did this today and followed the excellent instructions. I wasn't having all the symptoms as others have described but the tickover seemed a little high at 1200rpm and the throttle response was slightly hesitant. Anyways, I figured it was worth a go!

I came a bit stuck getting the small air hose and power connector off but managed to figure the little clips out in the end! Also didn't have a set of long reach pliers so struggled getting the main air intake hose clips back on. Nothing like having the right tools for the job :) Apart from that it all went smoothly.

The throttle body was very dirty and came up like new after a clean. After putting it all back together the tickover is now around 650rpm and the throttle response does seem improved. I would reccomend anyone to do this!

Thanks again for the instrctions :lol:
 
#28 ·
You're very welcome! :) Thanks for reporting your success!! 8)
 
#29 ·
Saw this excellent "How To" when it first appeared and have been itching to have a crack ever since. Didn't have any of the symptoms of jerkiness etc but thought it could probably do with a clean after 48k miles.

I bought all the bits n pieces a couple of weeks ago, along with a pipercross panel filter that I got this week and decided to finally have a go yesterday. Swopped out the panel filter first and proceeded to remove the air hose next, only to find it was spotlessly clean anyway! :? So, I just put everything back together and did the reset procedure.

What sort of mileage are other peoples cars at, that have had to clean theirs?

One thing I did notice on removing the air hose, was that the butterfly was partially open. Not much, only 3-4mm but I was just expecting it to be closed. Is this normal?
 
#30 ·
PeTTe-N said:
Saw this excellent "How To" when it first appeared and have been itching to have a crack ever since. Didn't have any of the symptoms of jerkiness etc but thought it could probably do with a clean after 48k miles.

I bought all the bits n pieces a couple of weeks ago, along with a pipercross panel filter that I got this week and decided to finally have a go yesterday. Swopped out the panel filter first and proceeded to remove the air hose next, only to find it was spotlessly clean anyway! :? So, I just put everything back together and did the reset procedure.

What sort of mileage are other peoples cars at, that have had to clean theirs?

One thing I did notice on removing the air hose, was that the butterfly was partially open. Not much, only 3-4mm but I was just expecting it to be closed. Is this normal?
Mine had 40K on the clock when I did it a few weeks back now.

The gunk on the *other* side of the butterfly was much more than the air-box side. I reckon you chickened out ;)

But seriously, if it really was spotlessly clean you probably didn't need to do it, especially if you had none of the symptoms. Maybe a previous owner already cleaned it? I'm surprised there isn't *any* muck in there...

The butterfly is meant to be a tiny bit open - nothing to worry about there. That's the idle setting.
 
#31 ·
Marty said:
The gunk on the *other* side of the butterfly was much more than the air-box side. I reckon you chickened out ;)
lol Didn't chicken out as such but couldn't see much point stripping it down when it was so clean :lol: It really was as clean as your picture that you posted on step 4 (post cleaning). I was a bit disappointed truth be told, was looking forward to having a little tinker with it. Haven't messed with a car for 25years or more but since having the TT it's something I'd really like to get back to doing.

Great "How To" though, it inspired me to dig out my tools and have a go. Keep them coming, I'm looking forward to your next one in the series!! :p
 
#32 ·
This is a excellent write up :D so can I do my 180 and reset the TB as described and not have to use Vagcom to do the re-set. if so I think I will give this a go.

cheers steve
 
#33 ·
stevebeechTA said:
This is a excellent write up :D so can I do my 180 and reset the TB as described and not have to use Vagcom to do the re-set. if so I think I will give this a go.

cheers steve
My write-up is specifically for the 3.2 which is very different to the 1.8

Here is a link others have used as a guide for the 1.8:

http://uk-mkivs.net/forums/t/127279.aspx
 
#34 ·
Had a go at this today....

Took the hoses off and the inside of the throttle body was pretty spotless .... so thought better of tinerking further. Was hoping to find it all gunky and a clean bringing improvements.

Was a bit of a an arse job with the pliers - two people would make it easier - one person loosen off the clips and then the other twist the hoses to get them off.

I did however manage (I hope) to sort the rattle on the passenger side - took the panel off and relocated one of the rubber bits to sit above the door "peg" above the speaker - problem solved. Might have to get a load of these and put them all over!!! Hoping for distortion free music on the way to work tomorrow!!! :D

Changed the air filter on the w/e the one in there was minging.... there was a leaf stuck in it and some polystyrene balls in there too. Hoping a new filter helps everything (bought it at the TT shop - interesting visit - lots of 3.2s there - some DSG problems.

Onwards with the tinkering....

Anthony
 
#35 ·
Take off your intake pipe and spray a foam oven cleaner through the throttle body, works a treat :)
 
#42 ·
I have been having some hesitancy issues as well as heavy steering, and seeing as i had some time off over easter, I thought it was time to sort them out.

I had a brand new DSG and mech fitted by audi at the start of the year, so i knew it was probably not that. So friday i had the wheel alignment sorted, and the power steering fluid checked, which was pretty low. (it had been causing some noises when turning hard left at low speeds). It now goes round corners smoothly, far lighter and with no noise. brilliant. I then got all the gear needed for the throttle clean, and what a result. the power delivery now feels smooth, no more jerky take offs or hesitant acceleration, it was silky smooth all the way. So, my 2005 3.2 dsg now takes of smoothly, changes gear perfectly, accelerates as it should, and goes nicely round corners. well worth the effort, a great write up, thanks!
 

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#43 ·
Do you actually have to take the throttle body off I have seen many people just leave it on and clean it like that then just start the car and let it run just incase spray went through but it was ok to have the spray go through so can I just leave it on and do it like that?

Cheers
Kit
 
#44 ·
kitcar98 said:
Do you actually have to take the throttle body off I have seen many people just leave it on and clean it like that then just start the car and let it run just incase spray went through but it was ok to have the spray go through so can I just leave it on and do it like that?

Cheers
Kit
That's the lazy way, which doesn't do the worst of it : the other side. It's not hard to do it properly :)
 
#45 ·
ok are the bolts hard to get out or one of them and how tight does it have to be when i do them back up?
 
#46 ·
kitcar98 said:
ok are the bolts hard to get out or one of them and how tight does it have to be when i do them back up?
Sorry, didn't spot this until just now... I guess it's too late, but one of them is hard to get to. It's do-able with the right tools though. Just be careful not to drop the removed bolts in the engine bay. I used one hand to undo the last of the threads and used the other to catch the bolt on the way out.

As for tightening, I didn't have a torque wrench nor do I have the required torque figure (if there even is one?)... I just did it up tightly by hand with the ratchet. It was tight to undo, so it should be tightly done up :)
 
#48 ·
Marty said:
kitcar98 said:
ok are the bolts hard to get out or one of them and how tight does it have to be when i do them back up?
Sorry, didn't spot this until just now... I guess it's too late, but one of them is hard to get to. It's do-able with the right tools though. Just be careful not to drop the removed bolts in the engine bay. I used one hand to undo the last of the threads and used the other to catch the bolt on the way out.

As for tightening, I didn't have a torque wrench nor do I have the required torque figure (if there even is one?)... I just did it up tightly by hand with the ratchet. It was tight to undo, so it should be tightly done up :)
yes bit late haha :) its all ok I didn't loose any of the bolts and found it was quite easy to do and all is good now much cleaner and better throttle response :)

Cheers Kit
 
#49 ·
markwartd said:
Here you go - The Red Leather really isn't as red as the picture - I wasn'too sure about it at first (maybe a bit poncy), but I love it now - it's something a bit different.

I could only attach a photo via attachment - sorry.

Regards
Daniel
Is the comfort pack just the coloured steering wheel? Or is it different some way?
 
#50 ·
kitcar98 said:
Marty said:
kitcar98 said:
ok are the bolts hard to get out or one of them and how tight does it have to be when i do them back up?
Sorry, didn't spot this until just now... I guess it's too late, but one of them is hard to get to. It's do-able with the right tools though. Just be careful not to drop the removed bolts in the engine bay. I used one hand to undo the last of the threads and used the other to catch the bolt on the way out.

As for tightening, I didn't have a torque wrench nor do I have the required torque figure (if there even is one?)... I just did it up tightly by hand with the ratchet. It was tight to undo, so it should be tightly done up :)
yes bit late haha :) its all ok I didn't loose any of the bolts and found it was quite easy to do and all is good now much cleaner and better throttle response :)

Cheers Kit
Cool. The guide seems to be useful to quite a few people. I'm glad to have given something back to the forum :)