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Discussion Starter · #1 ·
Hello to all....I have a 2000 E39 that I suspect needs a MAFS cleaning....can someone help me with the procedure. Thanks.
 

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97' 540i
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This what I do, and I'm sure you will get many other ways...

Once off take a large zip baggy, and fill it with a bottle of 92% alc. ( about a $1.50) the kind you find in the store drug section , its next to the rubbing Alcohol.

Put the MAF in the bag, zip it, and swish it around, for like 5 mins.. this cleans it good, inside and out.

Take it out and let it dry for 30 mins, if it is wet when you put it in... it will toast everything.

Thats it.. no need to buy any thing else.
 

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Seek to understand,^Value
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From a quick /MAF(F3) in the best links thread ...

- Mass air flow sensor (MAF) and idle control valve (ICV) require periodic cleaning (1) (2) & buying a replacement MAF cheaper than the BMW MAF (RangeRover MAF) (VW MAF) (Hyundai MAF)
 

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I use CRC MAF cleaner. If you do a google search for it, there are several utube videos on how to clean the sensors. Some use the spray with a very gentle brush. Personally, I just use the spray and let it evaporate, no brush.

If after 1 or 2 cleanings, your MAF rate doesn't increase, I would replace the sensors. I consider them maintenance items anyway and replaced mine at 100k miles evern though they didn't exhibit any problem.

http://www.google.com/products/cata...=X&ei=VryhTcftBNHQiALaqfmLAw&ved=0CDwQ8wIwAw#
 

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I am a believer! :thumbup: I just cleaned my MAF and there is a definite difference! I am still getting my cat checked tomorrow, but WOW, such a simple maintenance thing to do!
Quick step by step for a '98 528i
- remove the 2 10mm screws holding the airbox (you don't have to pull it out, this will allow
you the wiggle room you'll need later)
- use your flat head to loosen the band on the engine end of the MAF
- use your flathead to pop the 2 spring clips on either side of the MAF where it connects to
the airbox
- unscrew the wire harness, it has an externally rotating ring
- use your fingers to apply counter pressure to the MAF and you thumbs push on the
assembly that leads to the engine.
- pop out the MAF where it connects to the airbox and spray away with the CRC MAF cleaner
(5.99)
- Just note there is an O-ring seal insside the airbox that might get caught on the MAF as
you pull it out depending on how hard of an angle your working with.

The whole thing took me ten minutes!
 

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Discussion Starter · #6 ·
Thanks for the info everyone...great help....i cleaned and i did feel the difference...the ses light though is still on...should i clean the icv as well? Will this light turn it self off or do i have to bring it to a shop?
 

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Seek to understand,^Value
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the ses light though is still on...
How can anyone possibly troubleshoot properly without you telling us the codes that triggered the SES light?

Will this light turn it self off or do i have to bring it to a shop?
Oh my! I just realized you may not have read the codes yet. Is that the case?

If so, why not spend the $25 (at least that's how much it costs in the USA) to buy the code scanner and reset the light yourself?
- Cheapest CAN OBDII scanner on the net that reads DTCs, pending codes, & clears codes



Otherwise, you're just guessing (and, more importantly, wasting everyone's time, including yours!). :)
 

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Just to clarify, for those who have not done so already, whenever you clean the MAF, DO NOT TOUCH IT (physically). Don't use a towel to wipe it dry or Q-tips to really get at the corners. Just let it air dry or you might damage the MAF.
 

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Under the lift arms
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I just wanna hit this on the head once and done ,
Every Ase tech will tell you this is bad
Checking the voltage is how you test a maf, cleaning a maf is how you get to buy a new one
 

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Seek to understand,^Value
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Checking the voltage is how you test a maf, cleaning a maf is how you get to buy a new one
I want to clairify only. I have no position to take or defend.

Are you saying that cleaning the MAF, with a MAF spray, and w/o touching it, is NOT advised?
 

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Under the lift arms
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Everything in the book says yes, don't touch it don't clean it

It's precision electronics, dropping it, disturbing the element inside anything like that is a no no ( from the shop side of business)
I'm sure many have done it but I'm sure there's a few,here who have done it and then replaced it afterwards....
 

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i have over 200k miles and have never touched it and never had a code on it.
 

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Under the lift arms
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They really don't go bad when they do the voltage will be out of range and it will throw a voltage out of range code.... not to be confused with short to ground or open circuit

Sent from my ADR6300 using Bimmer App
 

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Anyone know of a good MAF on sale? My E39 is sometimes throwing odd mixture codes (Indie says) it may be the MAF causing this.
 

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"Once off.............
Thanks but I'm trying to get some simple but concise tips (and a video would be a plus),
on just how to access/remove it and the proper way to clean and put it back together.
Could you please provide the precise removal and cleaning procedures?

Much thanks in advance for your help.
 
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