DIY: Idle Control Valve Clean (including photos)

[bmw325i 0]

Got sick of my inconsistent idle and smooth return to idle when driving so pulled the ICV (Idle Control Valve) out of the car and thoroughly cleaned it. Here is roughly how its done for those that are keen to give it a shot on their own cars.

Things you will need:

1 flat head screw driver (normal size, not too big)

1 Ratchet with 10mm socket and short extension

1 Can of Clean-a-carb

Note: DO NOT use any silicone or CRC lub once you have cleaned it, other wise any grime, dust, etc will stick to it and will clog up quicker than you can say F**K.

Also DO NOT have the key in the ignition when you are doing this and DO NOT turn the ignition on until everything is plugged back up and you have double checked all electrics have been properly plugged back in, or it WILL throw a fault code which will cost you $$$ so double check it!

Step 1:

Pull out the airbox or podfilter if your a boy racer ha jokes, for this you'll need to undo the two 10mm nuts holding the airbox to the wheel arch, then pop the two steel clips off the MAF (Mass Airflow Sensor) and then take the airbox out.

Then take the pipe/duct out that is connected to the alternator and the front diversion cover thing, you'll need the flat head screw driver to undo the hose clamp from the alternator end.

Step 2: Take the plug off the MAF by twisting it anti clockwise and it should fall out, and put it out of the way so you don't stand on it (very expensive mistake). Then take the intake flexi-pipe off the throttle body and pull the pipe off that is on the bottom side of it (may take a good pull so don't be afraid to do so. (Also i'd recommend replacing the intake pipe if it has cracks or splits in the creases ($50-$60 brand new).

Step 4: You will see the oil dipstick is mounted to a small bracket type thing and there are 3 gold coloured 10mm bolts, one of which will get the dipstick out of the way, the other two are to support the ICV so undo all 3 of these and be careful not to lose them down the engine bay somewhere.

Step 5: Follow the pipe back that you pulled off the inlet flexi-pipe until you reach the other end of it which is slight under the manifold, give it a tug downward which should pull the ICV off the manifold allowing you to maneuver it around enough to get it out, NOTE: there is a plug on the end of the ICV that needs taking off first so dont pull on it too hard or you might find the plug good for nothing when you try and put it back on. When pulling the actual unit out it may be easier to get it in a position to take the pipe off it by undoing the hose clamp with a flat head screwdriver and then pulling it out through any gap you can near the fire wall or which ever works for you.

Step 6: You will now have the ICV in hand so get ruthless with a can of CRC Clean-a-carb (NOT CRC Lubricant or WD-40 as it will stick). Thoroughly clean it through each side of the valve and work a rag around in it with your finger and just clean it right up until its at a satisfactory condition again, Also give it a good spray down each side whilst shaking the ICV and you will notice the actual valve it self start rotating, keep doing this just gently until it moves nice and freely, then give it one more spray "for the road".

Step 7: Now the fun part of getting it back in, you will need to put the plug back on as soon as you get the ICV in a position to do so, then push it back in under the manifold (have a feel around first with your fingers to find where the hole is that it needs to push back into (This will be basically straight in where it was originally mounted and then straight up (sounds familiar really doesn't it ha). Then like I said, wiggle it back in under there and push it back onto the manifold and do up one or two of the 10mm bolts. Make sure its defiantly hard on there and then replace the oil dipstick mount and line it up to the hole and put back in the 3rd and final 10mm bolt.

Step 8: Your out of the woods now so all that is left is putting the black pipe back on that leads from the bottom side of the ICV to the intake flexi-pipe ad be sure this goes on completely, then do up the hose clamp on the ICV end.

Put the intake flexi-pipe back on and tighten the hose clamp, then the black ICV pipe needs to be pushed firmly back into the intake flexi pipe (on the bottom side of it where it came from). Once this is done all that is left is putting the MAF back onto the intake flexi-pipe and tightening the hose clamp, followed by replacing the alternator cooling duct and tightening the hose clamp onto that and lastly, put the airbox back in and attaching it back onto the MAF, push the steel holding clips back on and tighten up the 2 10mm nuts that hold the airbox in place. Plug in the MAF plug by gentally turning it clockwise until it locks into place.

DONE. now enjoy a smooth idle and a different (better) car to drive!

Edited October 21, 2009 by -ISLE69-

[curryinahurry 38]

sticky.

[bmw325i 0]

yeah could be a good option. its nothing too flash but it makes a difference and im sure theres more people out there that would benefit from doing it. I looked all over the place on how to do the M52B28 motor but could only find early M50B25's and 318 motor write ups and they are located in a slightly different place etc so thought id put up how to do this one.

[*Glenn* 854]

Havent had time to read all this properly. I will do later. One thing I will say is you need to warn people to remove the key from the ignition while the work is being done and dont turn the ignition on untill the car is back together and every thing is hooked up correctly, or it will throw a fault code. You also need to clear adaptions with a scan tool after doing this.

[1rotty 40]

Nice DIY

One point tho: I have been told NOT to use carb cleaner on the ICV as it is too harsh

In fact my can of 'Nulon' carb cleaner states 'not recommended for use on ICVs'.

Any comments guru's?

[bmw325i 0]

Most articles i looked over mentioned carb cleaner or pure alcohol. It worked fine on mine and if all else fails worry bout it then ha. "she'll be right"

[*Glenn* 854]

We use carb cleaner and white spirits...never had a problem. We also have some very small brushes for ICV's and throttle bodies. A modified tooth brush is useful. I also lube the ICV's with Wurth HHS 2000.

BTW..I wouldnt use carb cleaner on a MAF

Edited October 21, 2009 by *Glenn*

[twisted 45]

Nice DIY

One point tho: I have been told NOT to use carb cleaner on the ICV as it is too harsh

In fact my can of 'Nulon' carb cleaner states 'not recommended for use on ICVs'.

Any comments guru's?

I used AFM cleaner on my m60b40 ICV and it worked a charm. I've also used Subaru upper engine cleaner on my subbie ICV's.

[DarinD 8]

Just did this on my 323. Took about half an hour (its a pain to get the ICV itself out from under its hiding spot and then back again!). However for that half an hour it made a very considerable difference! Would recommend everyone do this if it has not been done already =D And clean the throttle body while you are at it if required.

[benpaul12 62]

Has anyone done this on an N52 engine on here? Or done this recently?

I've done some reading and this sounds as if it might be causing my slight idle issues...

[benpaul12 62]

Ignore, the N52 doesn't have an ICV, it only has the DISA!

[Herbmiester 909]

Good writeup, I did the same to my 330ci about a year ago and it made a noticeable difference to the idle quality.

[zero 1160]

Yea, I do this on every new car I get. Also clean the throttle body while you are in there.