Yidney

I've read several posts about cleaning the MAF as the possible solution to rough idle problems and I've seen Wes' how-to post. I also read a detailed how-to post over in the W210 forum that said that there is absolutely no good reason to clean the MAF as part of regular maintenance - basically wait for a problem or a code. There may be a good reason for that advice, but I don't know what it is. If a MAF can cause a rough idle or a code due to a buildup of deposits, why doesn't it make sense to clean it semi-regularly before deposits build up, especially since the job is not very hard? Seems to me that with a delicate sensor the cleaner the better. Anybody clean theirs every 25K or whatever whether it needs it or not? I note that the can of CFC MAF cleaner says to do it every time you change air filters.

Supafly

i clean it frequently....usually everytime I clean the air filters...10 min process...

dynomite05

You could definitely do it proactively. Mine actually crapped out on me last week. My mechanic actually replaced the insert instead of the whole MAF.

sleepyheadzzz

i cleaned it out this weekend my car is spanking smooth now...i had KN filters and they really trashed my MAF up with gunk....my car would hesistate when slowing down at lights...now its sooo nice and smooth...the hardest part is taking the MAF out...

Benz8

stupid question whats the MAF...

Klinh

The insert is the sensor itself. The whole MAF included a new pipe. It easier just to replace the insert.

Klinh

MAF=Mass Air Flow. It also known as MAS=Mass Air Sensor. It job is to measure incoming air to the engine.

dynomite05

Cheaper also. Since I'm getting rid of the motor soon, I didnt want to spend that money.

Yidney

When you pull off the big plastic thing that holds your two air filters it fits over a round housing at the back ofthe engine. Inside that housing is a sensor that monitors the density and amount of the air passing by - it's mass. Based on that measurement the engine computer knows how much fuel to use, etc. It's a delicate little thing that can get covered in gunk passing by. I cleaned the one on my wife's XC90 last night (37k) and it went from looking like it was supposed to be flat black to being shiny silver.

In the old days engines worked on the volume of the air going into the intake, regardless of its mass. That's not the most efficient way to use fuel and created some really bad problems if you had a drastic change in elevation. If you drove from sea level to the Rockies you could be blowing black smoke out your tialpipe because the fuel mixture was way too rich becuse the air had way less mass per equal volume.

Benz8

awesome great info thanks guys thats why im here not to pay some rip off to do work on my car

DisplacedTexan

what cleaner are you using to for this?

Yidney

CRC, the company that makes all sorts of automotive sprays, like Brakekleen (sp?), and various electrical component sprays, makes one called MAF sensor cleaner. You can get it at most any NAPA store if not Autozone. You can find all sorts of recommendations online of things to use, including CFC's normal electrical sprays, but with a sensor that is very sensitive to residues, for the $6 it costs why not use the one designed for that purpose. Don't wipe or touch it - just spray it.

M-bENZ

CRC is the way to go....

dark knight

I tried to remove the MAF sensor yesterday, spent half an hour and could not figure out exactly how to without breaking something.

I search all over and could not find any detailed instruction/DIY.
Can someone please post details of a proper way to remove the MAF.
Thanks.

2MCHCAR

Check this out :
https://mbworld.org/forums/c-class-w...-goodness.html

dark knight

Beautiful !!! Thanks.

mecca281

Hello my fellow Benz enthusiasts! This is my first post on this forum but I have to say I have been reading and have gotten so much great info from you guys on here!

I've owned my CLK350 since 08' and I just recently decided to start doing most of my services on my own... So far I have successfully serviced:

Engine oil and filter
Cabin air filter and engine filter
Adjusted brake cable slack
Cleaned MAF sensor

I have been pleasantly surprised how easy some of these services actually are!
I plan to change my transmission fluid and filter next.

Ps. Not only am I a newbie with mercedes work, I'm an auto DIY newbie in general. I'm great with home equipment... I plan to be great with auto also.

mecca281

Oh also might I add... My baby is purrrring ever since the MAF cleaning.

Guess as a control systems design engineer who deals with flow elements in the oil and gas industry I'd have figd this a while back.. Smh.

Rudeney

FYI, the transmission fluid change on your 722.9 7GTRONIC is not a simple drain and fill. I'm not saying you can't do it yourself, but it's a bit involved. One thing is that you need to be able to lift the car enough to work underneath, with the engine running, and keep the transmission pan level. There's a sticky at the top of the forum on this. Read through it and make sure you can handle it.

mis3

Last time I asked my indie to clean the MAF, he said since the MAG was not touched for a few years, replacing it would risk breaking other things.

Maybe he is concerned that the 2 clips would break.

mecca281

Hmm... I watched a YouTube on the S class that seemed ok, nothing on the w209 though. ill check out the sticky. Thanks

mecca281

Freaking clips!
I bought a bunch of little black zip ties for all the broken clips.
Zip ties are my new friends!

mis3

We cannot buy and replace these clips?

Rudeney

Yes, you can buy a replacement MAF sensor clip. It's not terribly expensive - maybe $25? I can't remember - I have to replace that, the throttle intake elbow, and every bit of vacuum hose rubber on the C240 and It was about $150 all totaled.

mecca281

yeah, i dont consider myself to be a cheapo, but something about spending $25 on some clips (that shouldn't have broken anyways) ticks me off

i mean dammit i didn't lose 1 clip on my toyota. LOL