How to clean your MAF

Parrot of Doom

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note: The original thread including all replies to this is located here > http://forums.mercedesclub.org.uk/showthread.php?t=18298

Feel free to point out any glaring mistakes I made while doing this :)

My engine has been playing up a bit, surging when cold in the morning, occasional misfire. Chief suspect (and cheapest to investigate) was the MAF, cleaning it would certainly do no harm. So heres what I did:

First, open the bonnet (duh!). The MAF can be found exiting the air filter box for the engine. On mine (300TD) its on the offside of the engine bay, at the front. You can see a small electrical plug attached to the air intake.

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1) Remove the plug

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2) Unclip the air filter box

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3) Undo the MAF from the hose by unscrewing the Jubilee clip.

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4) Remove the MAF from the air filter box, using a philips screwdriver (2 screws, 1 is hidden slightly) Once the screws are undone, you have to tug quite forcibly to pull the MAF away from the filter box. There is a large O-ring between the two, once separated check the O-ring to see if its in good condition. If its a bit knackered, get a replacement.

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Parrot of Doom

Parrot of Doom

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This is the O-ring:

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5) Once the MAF is separate, you'll be able to see what kind of condition its in. Mine was full of flies and muck. The inside of the MAF was also covered in a thin layer of oily muck. You can see the element at one end of the MAF, its protected by a plastic grid. Don't be tempted to touch the element at any time, its quite delicate.

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Oily scum:

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6) To clean the element, spray Isopropyl Alcohol onto it. I used just enough to get rid of the most visible contaminents. I also sprayed some around the inside of the MAF to help dissolve the oily muck that was there. I used kitchen roll to wipe this clean, although obviously I could only get to the first 2 inches or so. I sprayed on both the open side of the MAF, and the protected part of the element.

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This is what came off the element:

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Parrot of Doom

Parrot of Doom

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Now while I was doing this, I thought I might as well clean the pipe to the turbo, and the little pipe that heads off into the engine block. So I undid the jubilee clip holding the hose to the turbo, pulled the pipe from the engine block (it just slides out), and sprayed them both inside with lots of Isopropyl. Then I ran kitchen roll through them both and removed the oily slime from inside. You probably don't need to do this, but it can't do any harm.

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This is the exposed turbo intake. Probably not a good idea to touch that :)

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Utterly filthy pipe from the MAF to the turbo:

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Once everything is dry, put it all back together in reverse order. Make sure nothing drops into the pipes when you're refitting.

Does it work? No idea. Haven't driven it yet, and its warm so the engine doesn't surge much this time of year. I'll let you know if the car's behaviour changes at all. Remember to give things time to dry, the alcohol should dry very quickly but if you saturate it and then put it all back together, the system will suck it through. Doubt it would do any harm whatsoever, but best to be safe.
 

monumen

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No maf !!!!!!!!!!!!!!!!

Hi,
Why isn't my life as easy as this lol.
My 1997 C230 Sport Kompressor is idling badly and extremely slow to pick the revs up so after reading loads of threads I thought it would be a doddle and back running perfect in a minit.................WRONG.
My set up is nothing like this. I have a butterfly valve like a choke control and after pulling pipes off and unplugging it nothing changed. Even ran the car with it off but still the same.
Anyone got any ideas. Throttle body ?????.
Also on this car it sometimes sticks in reverse. I have narrowed this down to the gear lever and when I loosen it off under the centre console it frees off.
HELP!!
Dave
Please feel free to e mail me monument7@btconnect.com
 

sistaffs

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New Maf - Brilliant

1999 CLK 230 Komp Auto - 83K

Had a terrible problem, like hitting a rev limiter then would run like a plug lead was off, but if I stopped, turned it off then restarted it would clear.

Ordered a new MAF off Ebay for £35.
10 minutes to fit.

Totally different car, smooth and quick, Lovely Jubbly.

Thanks for your advice!
 

motoroil

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Hi All!
I am writing just to say hello and THANK YOU for all the help.
In these crisis days having to visit the oficial service may hurt a lot so I decided to do the job by myself.
After changing the spark plugs, filters (all) and HV wires the car was running better but way far of it used to be. That was the time to INVEST some time reading the forums post related to my car's problem.
I was lucky enough to found post describing exactly my problems and all were talking about the MAF... What to say! I followed the Parrot of Doom's instructions and have the MAF almost "pristine new" and the car running great!
Thank you again for sharing this helpful knowledge.
All the best,
motoroil

PS. Please, excuse my poor English. I did my best with my 500 words vocabulary. :)
 

jamesmc

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Hey Motoroil

No matter how good your English is... it is very nice of you to post your appreciation for the help provided. Good luck with your MB :)
 

television

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Welcome to the forum motoriol and thank you :D:D
 

Brian23

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Can you use elecrical contact cleaner to clean the MAF?
Brian
 

motoroil

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Hi,
Thank you jamesmc and television, it is really a pleasure for me participate in this great forum.

Brian, the first attempt to clean the MAF was spraying it with electronic contact cleaner. What a mistake! I used one that is useful for cleaning potentiometers and sliding switches but it leaves an oily and also wet film on the surfaces.:cry:
After messing the MAF with the contact cleaner I made a call to a friend who is chemical engineer asking for bit of isopropyl alcohol... fortunately he had some available and kindly brought it to me (RUNNN! I prayed!)
In the meanwhile I decided to take of the sensor from its case in a way to clean both parts separately. I cleaned the case with detergent and washed thoroughly.
Then, when my friend arrived, I poured some isopropyl alcohol in an airbrush and sprayed the MAF sensor a lot. At this point I noticed that there were some particles sticked to the platinum wire and also to a rectangular area that is in one side of the sensor.
I decide to go beyond the recommendations of not to touch the sensor and cleaned up this particles using a little and very soft brush but did this job under a microscope with extreme care of what I was doing. After that I sprayed the sensor thoroughly again with isopropyl alcohol and then with air to help evaporate the alcohol.
The rest of the story was assembling it back, install the MAF in the car and turn the key (praying!).... vroooommmmm.... that was great! The RPM jumps to 5500 with no cuts at all!:D

Well, excuse me for all this chit-chat! That was my experience and hope that helps a bit!
Al the best,
Leonardo (motoroil)
 

fredkrueger

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C Class Coupe C220 CDi W203
That was a great DIY article on cleaning the MAF so I decided to carry out the same on my C220 CDi W203 at 63000 miles.

I was expecting it to be covered in oil however I was surprised to find the MAF and all pipes to be in as new condition so I did not progress any further. However I found a potential problem with wiring to a sensor thats bolted to the air cleaner box upper cover. The cable tie had pulled the cable out of the plug at a too tight angle causing the insulation to be stripped exposing the copper. I am not sure what this sensor does but I am sure a fault could of developed over time causing much headache.

So if anyone could tell me what this does and thanks once again for a great and useful post.
 

LuckyLuckyStar

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CLK 320 W208
I have a CLK320 W208 (X Reg)

I'm getting misfiring, speed sticking and engine light coming on. Star confirmed cylinders are mis-firing (thanks Miffy).
Was advised the following:
- Clean MAF
- Change Sparks

A family friend told me the same thing as the star diagnostic (but not which cylinders were mis-firing etc) just by listening to it and also advised the above steps.
I said I was going to have a go myself at cleaning the MAF which he didn’t advise to do...he said something about its better done whilst the car is still running and doing whilst engine is off my trip a light when the sensor is disconnected etc.

So whilst this guys seems to know what he's talking about I think everyone who has cleaned MAF on this forum seem to have done with the engine off - am i correct?

As for Spark Plugs he insists on getting them from the Mercedes Benz Garage (making use of his trade discount) and advised me not to go for the cheap ones at Euro Car Parts.

So 2 Questions
1. Is it ok to clean the MAF with 'carb cleaner' whilst the car is running?
2. Sparks - Do I really need Platinum/Iridium tip plugs?

Thanks in advance
 

Cole@MBS

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1. Is it ok to clean the MAF with 'carb cleaner' whilst the car is running?

Yes but she will knock like hell!!
 

Mr Teddy Bear

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I have a W208 230. I brought my plugs from EURO exactly the same plug, except the W in front of the part number was missing.....................and hlf the price!:D
 
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directpoet2

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New Owner and have a question about MAF in 03 c230

Hi Guys and thanks for all the post that are helping me with getting to know my car. I have a 2003 C230 coupe and the pics that are displayed on your post shows a different motor than mine. Do you have any pics that will show me where my MAF is located.
Many thanks if you could help me

Will
 
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Calvyn

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Can methylated spirits/thinners be used to similar be used to clean this>
 

television

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Can methylated spirits/thinners be used to similar be used to clean this>

Thinners will melt the plastic sensor faces, brake cleaner is OK, but just a careful wipe with a damp cloth over these sensor faces will do.

The sensors do go out of spec and cleaning will help some diesels, but few petrols unless oil through engine breathing problems

here is a cut away MAF and you can see the sensors
 


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