DIY: Cleaning/Replacing Idle Control Valve (ICV)-

[tEckniks]

im gonna help you out a bit, for me and everyone else reading!

Here are my DIY Pictures of my ICV Removal on my '99 M3 (I couldn't find anything on the net for that year)

Before:


Removal of Airbox and Alternator Ducting:



Removal of MAS Assembly:


Throttle Body Removal and ICV Location:



ICV:


I cleaned my ICV and now my car idles great and its fixed all my cold start problems. Good Luck all you 99 M3 people...

[BORGERDING]

What's best to clean the ICV with?

[libravcs]

Excellent write up, this should be stickied. This is a good time for all you OBDII guys to install that M50 intake manifold too! Better idle and more top end power, what else could you ask for?

uh..more useable low-end torque?

[CMG]

What's best to clean the ICV with?

Cleaner

[funcrew]

Just a thought for anyone who doesn't want pull everything out. Sea Foam is a great treatment for degumming and decarboning your engin and if you put it in using the small vacuum line going in the ICV, the cleaner will pass through it on its way into the engine. I would think as long as your ICV valve is good, even if its really dirty, a couple of these treatments over a couple thousand miles will clean it up nicely. Just did mine today and my idle jump completely stopped. The stuff if cheap and boy you can see all the carbon crap that comes out of your tailpipe in smoke form after doing it. Do a search on the forum for seam foam and the thread talking about how to do the treatment should come up.

Where does the other end of the ICV vacuum line connect to on a '95 S50?

[BimmaDave]

i got mine out with only removing the throttle body. quite simple really, your DIY requires more work than is necessary. Great write-up though!

[CorbanTek]

i got mine out with only removing the throttle body. quite simple really, your DIY requires more work than is necessary. Great write-up though!

Thats because yours is a 97 M3 and the ICV is up front above the alternator, the 99 M3 had the ICV relocated to the back behind the dipstick. I added those pictures because there wasn't any writeups for the 99 year...

[Xiphos]

What's best to clean the ICV with?

Carb cleaner works very well for this.

[varmint007]

Great write up, really not as hard as I expected.
Start up hesitation is gone!

[ptldM3]

I did mine without taking off the manifold it was a pain.

[varmint007]

I did mine without taking off the manifold it was a pain.

It's definitely not necessary to take off the Intake manifold on the '99 cars (maybe all OBD2?).

So great, there's the single advantage of OBD2 over OBD1

[billkm3]

Thanks for the great detailed write up.

[9T3 325iS]

Is there any difference between a an S50 motor and an OBD 1 M50 motor in regards to doing this?

[Testament]

My o2 sensor was disconnected when i bought my 318is (didnt know until i took the ICV out to clean it). Plugged it in and the revs were fluctuating between 1800 - 2000rpms and there was a smell of petrol as though the car was running rich.

Replaced the ICV with one i got from scrappys but i get the same thing so i'm running the car with the ICV disconnected. Any ideas whats wrong? I'm getting the o2 sensor replaced next week to see if thats the problem.

[Hova]

good thread, cleaning my ICV and changing my spark plugs turned my car into a champ on cold starts. Idles PERFECTLY now

[chr328is]

So in doing this on my 97, do you guys think it will help my random missfire also?

I got the same question as Julz,

Will this help my misfire too?

My idle is bouncy, but I know I have a misfire. A dirty ICV wouldnt be the cause of this would it?

[mstaytru247]

OP--->very nice write up did it today took me about 2 hours but im slow and made sure i cleaned up everything very well.

Hey guys, just wanted to let you know I did the ICV cleaning today and i did with WITHOUT taking off the manifold and i have pretty big fat hands so it can easily be done. took me about 1 hours to do ICV and another hour to do throttle body. If you are planning on doing Big Bore throttle body it is the perfect timing to clean ICV. I tried to used toothbrush but it was honestly waste of time b/c toothbrush head is just too big. I just used half a can of Teflon safe throttle body cleaner and man it looks brand spanking new now. I also sprayed a bit of silicone lubricant to keep the flap extra lubricated. I also completely bypassed at the coolant lines both to clean make everything less messy and also for performance reasons. The hardest part was getting the ICV out in my opinion b/c the damn rubber had been there for so long it kinda got stuck but once i got it out i gave it a extensive cleaning and just used those shop paper towles and it looks perfect now. When you take out throttle body, HFM, reducer, intake, and Alternator cooling duct there is plenty of room to work underthere. If you really want even more room you can take out the front intake manifold support brace and then everything would be even easier to take out / put in. car idles much much better already ( im sure some of that has to do with bigger throttle body). The car idles super smooth now and alot of the misfires at idle are now gone. car sounds much healthier at idle and idle has gone up just a tad. overall i'm very happy. you can take off the intake manifold if you want but its really not necessary at all and it will only add time to the cleaning process.,

my 2 cents

true i did not take off the manifold, dont be afraind to take the hoses out with the ICV they are simply connected to the intake elbow and are sized differently so no mistake putting them back. Disconnect the upper ICV hose from the inside behind the throttle body. and snake them through the rest of the hoses/lines. if someone already mentioned this good if not try it.


my idle still seems a little high (about 900 rpm) after driving for about 10 mins at a time twice but it seems to be settling in, no surges so far.
THANKS GENTS

[NHmfree]

It's definitely not necessary to take off the Intake manifold on the '99 cars (maybe all OBD2?).

Definitely true. I did mine without taking off the throttle body either. You just have to know what you're looking/feeling for.

I cleaned mine with throttle body cleaner. It probably took 1hr.

[smittyM98]

How does it work connecting/fitting the end of the ICV into the manifold?? Was doing an ASC delete and in the process I replaced the hose from the ICV but can’t remember how to hook up the ICV back to the manifold??