Want your car to run good? -Go home tonight and clean this (ICV 540i v8)

[PENER]

on 528i the ICV is under the intake manifold, in the area shown in the pic below. the easiest way to access it would be by removing drivers side HVAC "elbow" going from the microfilter, then using 10mm socket take off 3 bolts (1 for the oil tube guide and 2 for the ICV) and detach the electrical cable. that way you can remove the ICV with the rubber hose still attached to it. the hardest part, stupidly, would be trying to detach the other end of that hose (that is between the MAF and TB). I tried that approach, so I know it works.

[PENER]

however, having full can of TB spray I decided to put it to good use and clean the TB at the same time. therefore I removed air intake parts before the TB, as shown in the pic below.

[PENER]

below is a pic of TB cleaned nicely. the are of detail would be a second throttle plate. as far as the ICV cleaning goes, please remember to clean the opening under the intake manifold, where the ICV attaches, too. apply TB spray multiple times, letting it soak in and work between the applications. good luck!

[mookish]

And the results were...

[PENER]

...hard to say, as I had no problems at all. despite 158k miles my car is extremely clean with no oil consumption at all. if you asked me why did I do it then, well, I had a day off, decided to replace aux fan motor, slap on new fan clutch, and having some time left, clean TB and ICV. you could say I'm anal when it comes to preventative maintenance.

[mustang00]

I didnt clean the throttle body because its a separate job. Cleaning the throttle body meant pulling off the intake piping and it was just something i didnt feel like doing. Im going to put an intake on the car soon to make it sound better so I will probably just do that when I do the intake. I will also clean the MAF.

10 mins and better throttle response.

Awesome DIY!!!

[djetaine]

dont know if this has been said seeing as how i didnt read the whole thread but
"want your car to run WELL" dammit.

[crashtest22]

that is weird. As soon as i cleaned mine, its like my car gained a lot of low end response. The car reved smoother and didnt require as much throttle input to achieve the same acceleration. Im talking about in the morning when you first start the car up and drive off. Before, it was hesitating so bad i would have to give it 70% throttle just to get it to go. Now it pulls way harder at 10% throttle in the mornings and doesnt seem like im driving around with the hand brake on.

I have been having the same problem with my car.
in the mornings when cold you just keep giving it gas and all the sudden it takes off, rough idle, stumble at idle. I have replaced my plugs, ran injector cleaner and nothing has helped. I now have a leak in the radiator and will be replacing that on wed. I will be doing this at the same time. I am getting a little excited about this one.......

[Philboski]

I did mine on the weekend, but I haven't seen any posiitive results as of yet. It was still stumbly on start-up. Next stop, the plugs.

[ben99]

it is so easy to clean i might do it with every oil change....

The way this valve works is that it is simply a 'revolving door' that is opened or closed by electro magnets. The valve is slightly open at idle or when it has no electric current being applied to it. This allows air to go around the closed throttle plate and make the engine idle at the desired speed. If this valve gets stuck shut (closed), no air can go through the ICV or the throttle plate and the car will stall out or run really rough depending on how clogged up the ICV is.

When you start to drive the car, the ICV closes its door fully and does not allow any air to bypass the throttle plate.

If the valve gets stuck, then the door cannot fully close which results in more air going into the motor than what the car is expecting. This can cause the car to run rough during acceleration. Almost like a vacuum leak but not

When you clean it, it allows the valve to move freely from open to shut. This allows the car to operate properly. When the car is at idle, it reverts back to its static position of slightly open and keeps the car at the correct idle speed. If the valve is stuck open, then the car will have a rough idle because its getting to much air with the same amount of fuel.

That is why the car actually runs better when you clean the ICV. It doesnt only affect idle speed.

I might be missing something...but isnt the air already metered by the MAF regardless if it goes through the throttle body or the ICV? The hose from the intake to the ICV is post-MAF. If so, then how could this affect performance when not at idle? Regardless of what path it takes, there will be the same amount of fuel injected regardless if the air goes through the TB or the ICV since it is already passed the MAF. Am I missing part of the equation??


EDIT - Nevermind, I see now that the air into the ICV can come from either the Intake pipe or from some 2 other sources as well. Makes sense now.

[E39sporter]

What a awsome post. TOO BAD I HAVE A FREAKING 2000! What a rip off! Does any one know of this same technique in the newer 540's (2000). My car has the same sluggish response as yours (before you FIXED it). I was getting excited just reading all this. Was even gonna leave work early to buy some spray! AHHHHH!!!!!! a 2000 freaking 540...old enough to not come with the upgraded lights and new enough to not have a cool perfomance cleaning project for the day! what a rip!

AC

[zloy]

just did this in my car turned it on and it started chking so i quickly turned it off... i am scared..maybe i did not put it in correctly

[supark]

What a awsome post. TOO BAD I HAVE A FREAKING 2000! What a rip off! Does any one know of this same technique in the newer 540's (2000). My car has the same sluggish response as yours (before you FIXED it). I was getting excited just reading all this. Was even gonna leave work early to buy some spray! AHHHHH!!!!!! a 2000 freaking 540...old enough to not come with the upgraded lights and new enough to not have a cool perfomance cleaning project for the day! what a rip!

AC

Your model year has drive-by-wire and hence no ICV

[zloy]

just did this in my car turned it on and it started chking so i quickly turned it off... i am scared..maybe i did not put it in correctly

reconnected and everything is fine

[Cancan]

dont know if this has been said seeing as how i didnt read the whole thread but
"want your car to run WELL" dammit.

Thank you for this post! The grammar deficit on this forum is unreal. I dig reading the posts however, sometimes they are more difficult to read then the work itself...

Cc

[CaptnGeetch]

I drive a 2000 528i , Will cleaning the MAF have the same results ? My idle drops out every once in awhile. Only when cold...I was thinking the Dbl Vanos is going...any thoughts ?

[John 540i6]

dont know if this has been said seeing as how i didnt read the whole thread but
"want your car to run WELL" dammit.

sorry! In georgia, that is the correct way to say it.

[DJKraft]

This is just what I need it..Thank you..John..^^

[202henhouse]

This is a great thread with alot of info. Based on problems I'm having with my 528i it sounds like my icv is gummed up. Has anyone had the MIL light up due to this with the fault code reading Mass Air Flow Senser/Performance (08 in the Bentley Repair Manual)? When this first happened the engine would not run at all. It would turn over and die immediately. I repeatedly tried to start without trying to depress the gas (I found out later the car would run if the gas were depressed, although very rough). After about 6-8 tries the MIL light went on. When I ran my Peake Scan tool the code was 08. Thanks for all the info to date.

[///M297]

OMG, this will be my task for this weekend. My 97 528i is sso luggish compare with my friend 528i (wel my is 158K), now I may know why. Will report back after cleaning.
Ryan

[Kwaaahhh]

So I'm guessing 03' doesn't apply? My car is 530 w/30k miles.

[Rebel635csi]

Just did this on my friends 1998 528i

he just bought the car and when we both drove it it would sputter and feel like misfiring when low rpm throttle was given....as in when leaving a light or cruising at really low rpm...

read up on it here, and decided to do it.....i almost wish i didnt

that thing is soooo damn burried on 528's, you can just catch climses of it hiding behind the TB and under the manifold.

basically i ripped apart the airbox/maf/elbow to have room to work as well as the HVAC elbow and microfilter box....

Note. DO NOT FORGET TO DOUBLE CHECK THAT THE RUBBER GROMMET THAT FITS INTO THE INTAKE MANIFOLD IS STILL THERE WHEN YOU ARE PUTTING THE IAC BACK! i went to put the IAC back in and thought to myself...strange...it wasnt this loose when i was taking it out. I went and looked on my 530i with the M60 engine (that sucker jumps out at you on the V8's as opposed to the I6's and yea, it had a grommet) the grommet fell out and was found resting on the engine block....made sense after that.

while i was cursing all BMW engineers my buddy changed the spark plugs...they didnt need changing but he did it anyways...new owner, wants to know exactly whats done and what needs to be done.

he took it for a spin as i was too greased up and he said its a HUGE improvement...no stumbling...


Thx for the write up guys...

PS. The Exploded Diagram shown did not look like my friends 528i setup.

the IAC inlet/out were vertical and the hose from the main Intake piping was hooked up differently. FYI

[Soco]

So the 2000 528's don't have this part?

[oekundar]

I went and looked on my 530i with the M60 engine (that sucker jumps out at you on the V8's as opposed to the I6's and yea, it had a grommet) the grommet fell out and was found resting on the engine block....made sense after that.

And here I thought the 530i was an I6 as well...

[Speed25]

I didn't know so many 540s idled so badly!