This is a starter DIY thread on cleaning your intake valves. I have not made a DIY before so if you see I miss something, please chime in.
This isn't pretty but it should do the trick.


My car: 2007 335i 6MT Coupe. 51,000 miles. AR OCC since ~48,000. No meth. JB3/4 since about 38,000. 3" catless DP, secondary cats removed, DCI intakes, FMIC.
Never ran meth.

Intake torque specs: (Thanks to Slicktopttz)

15NM = 11FT-LBS

3NM = 2.2FT-LBS or 27in-lbs



Tools Needed:
Lots of shop towels
8mm Socket
10mm Socket
11mm Socket
Torx T20
Torx T27
Metric Hex bits
Small flat head screwdriver for prying connector tabs open
Various Brushes, I used gun cleaning brushes.
Lots of Carb Cleaner, B12 Chemtool or you could use seafoam. I used carb cleaner and B12 since B12 was half the price of seafoam. B12 has the same active ingredients as the carb cleaner.
I used about 4 cans of B12 and at least 6 cans of carb cleaner. Alot of the carb cleaner was used a propellant to blast the valves, so if you have a air compressor you can probably get away with less carb cleaner since you have a good blast source.

Anywho, here it goes.
Get your engine down to this level, I can do this in about 5 minutes and I'm sure lots of you have done it before so I started here with the pictures.

4 metric hex bolts to take off the engine cover.

You'll get to this view. At this point you've already taken off your air intake(s), if not do that now.




Start unplugging connectors, careful the tabs break easy as you can see.

Throttle body is next, just put a flat head under the tab and pry it up, it will click in the up position. Follow the tube down and find where it mounts to a bracket. Unbolt the charge pipe from this bracket for more room.

Next I unplugged the throttle body connector

Unplugging the o2 sensors, you don't have to mark these. They only fit one way, different lengths

On the underside of the intake by the rear turbo inlet you will find a black tube connected to the throttle body, unplug it. It's very similar to the black tube connection right behind the oil filter housing.
There is a rubber mount that slides on to a bracket connected to the intake, just slide it off and detach the wire holder connected to it as well






Under neath the intake lies this evil thing, some holder for connectors and junk. Mr. 5 was able to slide the box off the mount on the intake. To do that he lubed it up first.
Mine wouldn't budge so I took the whole bracket off the intake. This took the most time out of everything. There's 3 bolts, 2 are easy to get off, the 3rd is a bitch. Careful not to strip out the heads.

There are 6 nuts and 1 bolt for the intake, they are all 11mm.
Carefully pull the intake off. You'll have to push the rear intake piping out of the way a bit, but it will clear. If you see something thats preventing the intake from coming out,(I may have forgotten a step), carefully unplug it. It's pretty straight forward.
It's going to get messy, so try to put towels down to catch the dirty liquids. I covered the starter pretty good also since there's a hot wire right there.

Cleaning.
Cylinders 4-6 will be the worst.
You'll want to get the valves to close (TDC) so this gunk doesn't get into the cylinders. Best way is to just look at the valves, you'll be able to see if they are closed, 2 of them should be closed if not 3. I just tested by spraying carb cleaner into the valve and seeing if it puddled.
Once you have cleaned those cylinders and want to move on to the next ones you have to rotate the engine. The easiest way for me was to put the car in first gear and release the e-brake. The rock the car back and forth to rotate the engine until you see the next valves start to close. Works best if you push and pull from the front , that way you can check the valve movements quickly and see if you need to continue rocking. A good indicator of this is , you will hear a compression noise. When I heard that noise I stopped and checked and the valves had close, so listen for that hint.


After I found which cylinders were at TDC, I filled the TDC cylinder intake ports with the B12 cleaner and let them sit for at least 30 minutes.





Then just scrub a dub. This takes several tries as you cannot see the valve after you start scrubbing.


On to my macgyver method for helping get that crap out of the intake ports.

Basically took a wet dry vac, and attached (just let it suction it on) the top of spray paint can do it. Then I cut a small hole for a hose to fit in. So in the end you have a wet dry vac with a very small hose that can fit into the ports. Make sense?

So my method was to let them soak, scrub really good, then suck out the dirty cleaner with the wet/dry vac. While the vacuum is running and the hose is on top of the valve, I sprayed the carb cleaner all over the valve to blast away the loose carbon, that way the vacuum would suck it up right away. Similar to being at the dentist, when he uses suction and the water blaster side by side. The blast pressure from the carb cleaner helped alot and did most of the work.


After a few clean and dry cycles you will get a good result.


These threads helped guide me as well with some information.
http://www.e90post.com/forums/showthread.php?t=507653
http://www.e90post.com/forums/showthread.php?t=520035

Hope that is enough to help you guys, I may have skipped a step since I get pretty focused and in the zone while working on cars.
If you have any questions please ask.

When you get everything back to together and start the car, it'll stumble for a second then should go back to normal.

Remember to clean out that vacuum