Idle Control Valve Write up; ICV clean DIY

[Mr.M]

Note: If you cannot see the images, please PM me for them and I will email them to you.

So I did a search on cleaning the idle control valve and came up with question threads that had no answers. The DIY on bimmerDIY is essentially useless, so here’s one I hope will be of more use to M42 owners

If your idle is rough, changes rpm's, or just fails to keep the engine running, your IVC may be clogged and in need of cleaning. I was having a slightly rough idle and decided to do mine.

This DIY / write-up will require the following tools/supplies:
Flashlight would be helpful.
11mm socket
Flathead screwdriver
Throttle body (TB) cleaner
OEM hoses if in need of replacement
Throttle body gasket and intake manifold gasket (not technically necessary, but a good idea)

It took me about an hour to remove, clean, and put back the ICV. Plus I let the hoses dry (while out of the car) for about 20 minutes on top of that.

First, start by opening the hood with the engine off and hopefully not too hot, as you will make contact with the block and the intake manifold.

You will take off the intake tube, shown below, by loosening the screws at the blue arrows, and pulling off the hose at the red arrow. Then pull the intake tube off completely.



Next, you remove the throttle body, by four 11mm bolts. The top two are shown with red arrows below. The bottom two are on the bottom of the TB, in the same position as the top two.



Move the throttle body off to the side, to gain access to the upper intake manifold, like this:



Next, we'll disconnect the hose connecting the manifold to the ICV we wish to remove and clean. Behind the manifold, at the back of the engine bay, is the hose. Just twist it off, as shown by the red arrow.



Now it's time to remove the upper intake manifold. Undo all 5 of the 11mm nuts attaching it to the lower manifold. The nut locations are highlighted below with red arrows. The nut in the rear of the engine bay is hard to get to, but a small 11mm socket and 1/4" drive ratchet should get it out.



Next, carefully remove the manifold, by slowly lifting it up. I pried it off woodworker style using the backside of a hammer against the block. Be sure to remove it evenly though, lifting it up equally on all sides. Otherwise it will get stuck on the bolts on the manifold's drivers side. It is easiest to place it as shown:



Now we have acces to the ICV. As shown below, it is attached with a rubber strap at the point shown with red arrows. The blue arrows indicate the electrical connection, which pulls of when you press down a wire clip. They also point to the hose connections, which you will also want to remove. Note the arrow on top of the ICV. It points TOWARDS the block. The part label with Bosch and the BMW part number written on it also face the front of the car. This is important. You want to put it back facing the correct direction.



Now, take the ICV and clean it. The image below shows the ports into which the tubes were plugged, and air flows, with a blue arrow. You'll want to hit it with an old toothbrush and a gratuitous soaking with the TB cleaner. You may choose to clean the throttle body itself while at it with some paper towels and the cleaner.



Let everything dry, and clean off the hoses if you'd like. One of mine was cracked and therefore replaced, but washing the oil and grease off of them will help them last longer. Replace any that are cracked! They will make your idle worse and allow unfiltered air into the engine = bad. Be sure to let everything dry, especially items that were cleaned with water (hoses.) Installation is the reverse of removal. Be sure to connect ALL the hoses - double check!

And you're done! My idle was substantially smoother and more consistent. It made a huge difference! Good luck, and PM me with any questions, or if you are having trouble viewing the image.

Regards,

-Robert

[norcalbmw]

right on, ive been meaning to do this but am verry lazy

[adriver]

wish i had an m42 just so i can do this. nice write up for us noobs.

[TC535i]

Wow... on my '92 M42, I can just reach back there, wiggle it around, pop it off the mount and pull it out of all the connecting hoses. Takes me like 3-5 minutes.

[Mr.M]

Originally Posted by TC535i

Wow... on my '92 M42, I can just reach back there, wiggle it around, pop it off the mount and pull it out of all the connecting hoses. Takes me like 3-5 minutes.

What? I tried that for a while. There's like no access!

[maxell0405]

Excellent diy. A chimp could follow those instructions. Wish I could take pictures that good.

[BiMMa b0i M3]

i know that you have an M42, does it work the same for M50 also? just curious

[prophecy]

yes it will be similar on an m50, you'll be taking of the intake manifold and the airbox most likely unless you have like spaghetti hands.. its simple once you get to it

[Mr.M]

It should be pretty similar. There was a similar write up for the M50 on the forum, but when I looked it up all the picture links were dead

[shanecconn]

wow, this is such a good write-up i think i deserves a big bump as this problem still keeps cropping up over and over again with slightly vague and unclear solutions (mainly because of different engine types (4 bang & 6 bangers)).

This is by far the best write-up i've seen yet and thats saying something because alot of them are very, very good.

Well done Mr.M its nice too see someone still cares about the poor old 318 amongst all these big 325's and 328's.

kudos.

[kesslerbmw]

What is TB Cleaniner?

[jiggynites]

good write up the other diy write up suck so i did not even attempt to clean it. and reaching for it without taking off the upper part of the mani is a biatch you could be there for hours.

[Mr.M]

Originally Posted by shanecconn

wow, this is such a good write-up i think i deserves a big bump as this problem still keeps cropping up over and over again with slightly vague and unclear solutions (mainly because of different engine types (4 bang & 6 bangers)).

This is by far the best write-up i've seen yet and thats saying something because alot of them are very, very good.

Well done Mr.M its nice too see someone still cares about the poor old 318 amongst all these big 325's and 328's.

kudos.

Thanks for the compliment. The 318 doesn't get enough DIY love, and it was so frustrating not finding a good one on the topic. Hence, this thread.

Kessler: TB is throttle bottle cleaner. It's at the top of the DIY, in the tools needed section.

Jiggynites: I swear I still can't see how someone could get the ICV out without removing the manifold. Putting it back would have to be even worse.

[TC535i]

Originally Posted by Mr.M

Jiggynites: I swear I still can't see how someone could get the ICV out without removing the manifold. Putting it back would have to be even worse.

Dunno what to tell you guys... it was tight, but I could fit one hand behing and remove the rubber surrounding from the bracket, then unplug it from the hoses.

Even easier to work on with the DASC, it's sitting right behind the bypass elbow of the s/c, just hangin out.

[TC535i]

Just realized mine wasn't mounted where yours was... mine was on a bracket near the firewall, about halfway deep on the intake manifold. It was surrounded by a rubber ring that plugs into a metal bracket.

[Green318is]

In my car the ICV seems to be located in a different place than yours. It's not below the intake manifold. It's farther to the back, near the oil level dipstick, just as TC535 explained. Check picture 24 on page 130-16 of the Bentley manual. My car is a 1993 318is (Euro version). I can remove it without taking out the intake manifold.

[TC535i]

Originally Posted by Green318is

In my car the ICV seems to be located in a different place than yours. It's not below the intake manifold. It's farther to the back, near the oil level dipstick, just as TC535 explained. Check picture 24 on page 130-16 of the Bentley manual. My car is a 1993 318is (Euro version). I can remove it without taking out the intake manifold.

Mine's a '92. Seems like they made some changes to the M42 between the 92/93 models and the 94/95 ones, maybe this was something in that revision?

[shanecconn]

Brilliant, i copied your write up word for word (your right, that bolt on the back of the intake manifold is a byatch to get off) and now my car runs smooth and starts perfectly (even when the engine is hot). i didn't say before but it never started when it was warm , revs just went up to 1500rpm then dropped down to 0 and stalled.

Yeahh, i feel like i just got a new car, Kudos again. now all i have to do is get my new thermostat to sort out my "engine allways cold problem". should have the parts by next week to sort that out.

BRILLIANT!!!, no going to the stealership for me.

[shanecconn]

just noticed there that my hose going from the intake hose to the icv ain't branched like MRM's , whats that about , everthing else was the same.

[shanecconn]

also, i forgot to reconnect the hose connecting the manifold to the ICV and my god the car sounded awful when i tried to start it. i thought i'd just made my sitution a whole lot worse by cleaning the icv. god i was happy to see what i'd done wrong.

[Mr.M]

There are some small revisions that were made on the M42, and some big ones like the profile gasket fix. I believe the profile gasket was fixed with '95 models? If so, that would explain why everyone seems to have minor differences compared to my DIY: you all have 94's and older.

[antonk]

I just cleaned the ICV on my 92 318iS, and man was it ever easy to get to. You don't even need to "get" to it, it just sits there behind the exhaust manifold. Just take off the electrical connection, and the two hoses, undo the one nut and it's off. 5 mins of cleaning, and pop it back in. Easiest thing I've done. Car now idles smooth as a baby's bottom at least when the engine is warm. I JUST did this, so I've yet to test it cold, but I'm happy with how it idles when warm, because it's perfect. I guess there some benefits to 92s afterall

[psyyambmw]

Just see yr thread. Truly dedicate write up, especially m42ers.

However, I'd like to make a comment, over here. Hope U don’t mind.

When I doing this, I will not take the throttle body off. On the other hand; I will;

1st, remove GAS & Cruise Control plastic cable retaining and the o-ring rubber.

2nd, remove the plastic cable-end retaining clip. Take it easy, don't break it. Pull the cables out of the housing, respectively.

3rd, remove the vac hose.

4th, remove the throttle sensor plug.

Then, just remove'em, upper intake + throttle, as a one whole piece.

[lottathought]

Wonderful directions.
I had the laptop on the garage workbench and followed step by step.
Car is back together and working fine.

All guides should be this good.

Lost one of the 11mm nuts to the manifold....will have to replace it tommorow...but that is another story.

Looked for that nut for over an hour...no idea where it went.

[mdh]

The ICV can be removed and replaced on an M50 without removing the intake manifold. It is a tight fit to get your hands in there but I have personally done this twice.