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DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

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Old 06-30-2014, 03:29 PM   #1
OEM ///Member
Join Date: Sep 2009
Location: Australia
Posts: 246
My Ride: 330 Ci convertible
Project M54 engine: Dissection of an ICV.

Dissection of an Idle Control Valve (ICV)

Link to other parts of the project.

Iíve always had rough starting issues on my car. I identified it as an ICV that was getting that was a bit sticky, which required me to clean it out about every 6 months. After cleaning it would be perfect, but then after a little while it would occasionally give me the rough starting issues again.

I had an ICV that was left over from doing the engine project, so I thought I would try and pull it apart to see if they can be easily refurbished. I assumed the issue of problems soon after cleaning was the bearings inside being cleaned out of all lubrication by the solvent used, which needed fixing. I wanted to find out if was possible to pull it apart and replace bearings etc.

After removing the armature, I tried for weeks to work out how to pull it apart without damaging it. I couldnít work it out, so eventually I sacrificed it to the DIY god and cut it open.

In a nutshell, it would be very difficult to pull this apart and change the bearings over, but there is a way to lubricate the bearings. Iím going to tell you the process of pulling it apart, but I wouldnít recommend it.

Some basics on the ICV and how it works.
The ICV is fed an alternating current from the DME. This goes to an armature that changes its magnetic field so a rotor (with some permanent magnets attached) vibrates back and forth to an equilibrium position, which controls the rotor position. When you turn the ignition to position 2 (with the engine not started) you will hear a humming from the intake manifold area. This is the ICV vibrating. If you removed the ICV from the intake manifold and held it in your hand when it is activated (Iíve done this) it vibrates to the point of it being uncomfortable to hold. This is why it is rubber mounted into the intake manifold.

The thing thatís great about its design is that none of the electrical components move. The armature remains stationary, while the rotor and permanent magnets do the moving.

Pulling it apart is initially done by removing the three 2.5mm hex screws. These have epoxy resin over them to seal the unit, so you have to drill this out, and then pick out the remains with some type of sharp tool.

With the screws out, you need to grip the electrical connector with something and wiggle and pull to get the armature out. Itís in there really tight. I used some multigrips and pulled and wiggled for about 10 minutes to get it to come out. You can see the damage done to the electrical connector in the process.

Once the armature is out, you can easily remove the circlip (which is what the screws attach to), and then pull out the magnets and clips that are in the cylinder.

This is where I got stumped, and had to cut it open.

Here are the components.

You can see the issues with cleaning out the bearings. A lot of the lubricant in the bearings is immediately dissolved, initially clearing everything out, but then making the bearings drier, and not really fixing the problem. The needle bearing will get dried out very easily, and the roller bearing is metal shielded, so it doesnít seal particularly well either.

You can see on the photo above the knob that is on the end of the rotor fits into a slot that is inside the housing. When you are cleaning the ICV and rotate it back and forth, itís this knob that limits the travel. I was always worried I might be banging it against some electrical component inside, but this is not the case. You can rattle it back and forth when cleaning with no risk of damage.

Now the problem of pulling it apart. The unit is put together by installing the locking clip inside the housing, and then the rotor assembly is pushed hard inside until the tangs lock into the groove on the bearing. When the rotor is being installed, it compresses the spring (see top photo), which then presses back to lock the rotor in place when the clip tangs are engaged.

If you wanted to disassemble the unit, you would have to compress the spring, and disengage each of the tangs. No problem, except the gap between the cylinder and the inside of the housing is about 0.5mm, and you would have to have a number of special curved tools that could poke down there and disengage the tangs. Very difficult in my opinion.

The only solution that I could see was to lubricate the bearings after cleaning. I put some engine oil on the roller bearing, and rotated it back and forth. The oil went through the metal shielding slowly, and the assembly rotated much better after a while. Prior to pulling the thing apart, I had cleaned it the best I could using carb cleaner. Even so, the bearings were still binding a bit. After lubrication, it moved much, much better.

After seeing this, I removed the good ICV from my car. After cleaning, it was freely moving, but it sounded raw without any lubrication. I put a good squirt of engine oil inside the chamber and stood it on its end (both orientations) and rattled it back and forth so oil went into both bearings. It immediately sounded much better and dampened the movement (like a new bearing compared to an old dry one). I did this for about 10 minutes to get as much oil as possible inside, and then blew the excess out with compressed air. Iím of the opinion that if any more oil comes out, itís just going to go straight into the cylinder and get burnt.

Itís been in the car for a week now, and has started faultlessly every time. If I have any problems Iíll let you know, but for the moment Iím very happy with the results. Only time will tell me if itís a long term fix.
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Old 06-30-2014, 11:46 PM   #2
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Join Date: Nov 2011
Location: USA
Posts: 189
My Ride: 01 330i
Awesome info!
sunnyjay is offline   Reply With Quote

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