ICV Cleaning DIY - United Bimmer Community

**Dudesky** · 08-18-2005, 04:20 PM

All the usual disclaimers apply . . in short, do this at your own risk, blah blah blah. Also, people have different methods of doing this job, and I have mine.

This writeup is for an E36 M50 engine, but others will be very similar in execution. Rough idling can mean your Idle Control Valve is dirty and sticking. This should take under an hour to do, and requires minimal tools. It will, however take some patience because the hoses are a pain the ass to get off, given the cramped quarters you'll be working in. Most of the work involves moving some stuff out of the way so you can reach the ICV. My apologies to those of you with unusually large arms or hands . . you may have to do it the hard way by removing the intake manifold, which is not part of the scope of this DIY

Start by removing the alternator cooling duct (blue arrows).

Next, remove the intake air temperature sensor at the back of the airbox by unscrewing the 10mm bolt.

At the front of the airbox, disconnect the air intake duct.

Unscrew the two 10mm bolts that secure the airbox and cruise control unit (blue arrows).

At the back of the airbox, unclip the mass airflow sensor (clips shown by arrows).

Disconnect the mass airflow sensor at the opposite end, and move it to the side and out of the way. Now you will have enough room to get your arms under the intake manifold to reach the ICV. Note the hose indicated by the arrow. This is one of the two hoses that connects to the ICV. Unplug it at the location shown in photo.

Here's a (not so good) photo of where the ICV is located. Remove the wire plug at the front. Feel for a wire clip, and squeeze it in while you pull the plug off the ICV.

Here is a photo of the ICV removed. The hose on the right is the one you disconnected two steps ago. The one on the left connects to the intake manifold. Rather than removing the hoses at the ICV, it's easier to do it at the opposite ends, since there is no room to grab them with enough force at the ICV's location. Also note the type of hose clamp that is used in the photo . . you'll never get that off while it's under the intake manifold! The hoses do turn around the ICV openings, so spin them as you see fit in order to get the whole thing out from under the manifold.

Photo of the dirt and crud inside. Arrow points to the valve (or 'door') that controls the airflow at idle. Use rubbing alcohol, a toothbrush and q-tips to clean both openings well. Open and close the valve while you clean. Also pour the alcohol in there, slush it around, drain, and repeat. Let dry for about 10min, then spray some WD40 in there, and work the valve to get it moving smoothly.

Here's a photo of a cleaned ICV. Now put everything back in reverse order, and you're done!

**jrhaile** · 08-18-2005, 04:44 PM

Good write up... I did this last weekend along with flushing out my intake manifold. Note you do NOT have to take off your manifold to get this ICV out. Most people say you do but I was as was Dudesky. Besides, taking off your manifold requires you to remove the fuel rail too which is a nightmare because you have to disconnect the fuel lines which is messy

**komodo** · 08-18-2005, 05:17 PM

Very nice write up! This is definitely going in our knowledge base when I get it together.

Thanks man.

**defkon99** · 10-01-2005, 02:13 PM

zThanks for the DIY! i just finished doing this to my bimmer thanks again! for that Awesome DIY!

**LHerbert** · 10-30-2005, 09:13 PM

awesome DIY Dudesky. just finished and it worked out perfectly with a little muscle. the car feels totally different and it's great. i would definately recommend doing this if you have an idle that is anywhere less than perfect. thanks again.

**estorilm3** · 04-11-2006, 10:07 AM

I tried following the instructions provided above are these different for an M3? I cant seem to find the ICV? Can someone provide pictures?

Thanks

**Dudesky** · 04-11-2006, 01:02 PM

It's gotta be somewhere near the throttle body. I'm not familiar with the M3's layout, maybe this might help:

**estorilm3** · 04-11-2006, 02:27 PM

In picture 6 how on earth did you get the hose off

I'm worried about ripping it off its soft rubber and its not budging and then how to put it back on use some soapy water? I think I have found it now i just need to pull off both hoses and disconnect the electronic connector.

Thanks!

**Dudesky** · 04-11-2006, 03:43 PM

Just keep on tugging at it, it'll pull off. And it was actually easier to put back on

**estorilm3** · 04-12-2006, 08:13 PM

Doh I just realized my m3 is a m52 engine so thats why I'm having problems finding the darn ICV. My car is a 98 m3 sedan. I've looked high and low for that dam thing maybe i dont have one

hehe

**c1apton** · 04-13-2006, 03:46 AM

Quote:

Originally Posted by estorilm3

Doh I just realized my m3 is a m52 engine so thats why I'm having problems finding the darn ICV. My car is a 98 m3 sedan. I've looked high and low for that dam thing maybe i dont have one

hehe

Think so? Try this (item #6)

**Dudesky** · 04-13-2006, 08:13 AM

^^^Cool that helps a lot. I was gonna say, but I'm not familiar with the M3's . . I was thinking it has to have an ICV

**donald1476** · 04-13-2006, 04:35 PM

328's and M3's you have to remove the throttle body to get to it. It looks a little different than the one here but you should see it, it's a solid metal tube shaped peice right behind the throttle body under the intake manifold. I guess I'll do a write-up for the m52/s52 later.

**jybute** · 04-13-2006, 04:48 PM

Quote:

Originally Posted by c1apton

Think so? Try this (item #6)

clapton never cease to amaze.

**mitch500** · 04-15-2006, 02:01 PM

i beleive the m3 has a s52 not and m52, m52 is a 328 motor.

**nightdevils** · 04-17-2006, 02:32 PM

Quote:

Originally Posted by jybute

clapton never cease to amaze.

I concur.

**Racer X** · 11-11-2006, 07:58 PM

any word on that s52 ICV write up?

**215BIMMER535** · 11-12-2006, 12:47 PM

great DIY i have an M52 motor but i plan to do this next time im home from school and have a heated garage to work in.. my house up here is in "the hood" and i hate workin on shit in the street

**Dudesky** · 03-09-2007, 08:43 AM

Just a note, or rather, a correction:

In the 2nd photo of this writeup, the part depicted is incorrectly identified as the intake air temperature sensor. It is actually known as the airbox thermostat, and is connected to coolant lines which warm the throttle body. It helps to prevent air condensation at the throttle body. Sorry for any confusion

**kyleabaker** · 07-01-2007, 03:56 PM

I just completed this DIY on my 1995 325is and I'm not sure if it helped or hurt my cars idle problem. I got to the control valve out fine and cleaned it up with a tooth brush and q-tips and rubbing alcohol, and it did clean up great. However, after letting it dry for about 15 minutes or so I put the hoses back on and placed the icv back in place, then after starting up my car the idling seemed to be more extreme than it was before. I thought it mgiht straighten itself out if I took it for a short drive so I drove down the road and came back and it still has alittle trouble. It almost makes the car tremble a little. Before I cleaned it, my car would bounce around between 250-1000 rpms when idling and slightly rolling, like upto a stop light or something..but when the car would stop rolling the rpms would stablize. now it seems like the rpms are unstable both while rolling and while sitting still. Has anyone had this problem before..and if so what do I need to do to fix it up?

Thanks for any help.