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[nathan.d.kim]

This was done on a 2007 STI with 43k miles on it.

This is a simple maintenance procedure, but I've read that some people had no clue how to do it. So, I decided I would post some pics today so you can do it yourself as well.

1. Undo the wiring harness that goes into the MAF near the large diameter hose. The MAF sensor and hose is shown on the first picture, circled in red.

2. Remove the upper portion of the air intake box by undoing the metal clips and unscrewing the clamp that holds the box to the large diameter hose. The MAF is a small part of the upper air intake box, shown in second picture, that sits between the hose and the air intake box.

3. Use the MAF cleaner made by CRC. You can pick up a bottle at Advance Auto for about $7 bucks ($9 if you're in New Jersey b/c everything costs more here).

4. Spray the sensor with plenty of the cleaner inside the tube. Do not touch anything inside the MAF sensor area with your bare fingers. The liquid will dry by itself. It's flammable, so be careful with it.

5. Also spray the wiring harness that goes into the MAF sensor, which you removed before. Allow to dry fully before putting back together.

I haven't learned yet how to embed photos directly into the thread step-by-step. It's too late at night for me to try to figure it out right now. I'll edit it later.

[bzbuzz]

The second picture is IAT sensor.

MAF sensor is hidden in the middle.

[nathan.d.kim]

Oh? I guess you can unscrew the cross-tipped screws on the outside then and further break down the assembly, if desired. Or you can spray the cleaner all over the inside area. The metal filament sticking up with the brown wad on the tip is the MAF filament. Don't try to scrape off the brown wad or anything - I know someone who thought that was oil residue and destroyed the filament trying to fix it. Just clean with spray - no need to wipe anything down, use Q-tips, or anything like that. Spray and allow to dry whether you disassemble further or not.

[T_A_C_H]

Originally Posted by nathan.d.kim

Oh? I guess you can unscrew the cross-tipped screws on the outside then and further break down the assembly, if desired. Or you can spray the cleaner all over the inside area. The metal filament sticking up with the brown wad on the tip is the MAF filament. Don't try to scrape off the brown wad or anything - I know someone who thought that was oil residue and destroyed the filament trying to fix it. Just clean with spray - no need to wipe anything down, use Q-tips, or anything like that. Spray and allow to dry whether you disassemble further or not.

You shouldnt disassembly the maf sensor to fully clean it. Spray it on the inside and use compressed air if you have to lightly blow thru it to dry it out or let it air dry.

[ImranM847]

Originally Posted by nathan.d.kim

The metal filament sticking up with the brown wad on the tip is the MAF filament.

That is the intake air temp sensor. If you remove the two screws from the MAF/IAT sensor housing you can remove the unit and look down that tube to find what will look like two tiny wires. Those wires are actually the sensor portion of the MAF. Those are the things you want to spray cleaner on. You can use the red straw that came with the can of cleaner, but be careful not to touch or damage these small wires. Hope that helps somebody. Nice photos though!

[tegan_ca]

Originally Posted by Leftbehind126

And is this a regular maintenance kind of thing? If so after how many miles should it be done? Thanks

It is for me. I unclip and unscrew the maf sensor, spray w/the CRC, and let dry for 30 min before re-install.
I do it ~100 miles after cleaning my air filter (CAI w/K&N oil type filter). There usually isn't much on it because I'm light with the oil on cleaning the air filter, but it helped when I had my K&N insert in the stock airbox because filter was closer to MAF sensor.

So, I do it every 7500 miles or so (2x oil change) a couple days - 1 week after cleaning my air filter.

[Translucent]

Here's a picture of the actual wire (there are two):

Kind of hard to see the second one, but these are what need cleaned, not just the IAT sensor as mentioned.

[boxtwo]

8/17: cleaned up.