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Discussion Starter #1 (Edited)
Here is a simple DIY I created for fellow board members to remove and clean their MAF sensors.

**I'm not a professional, so do this at your own risk.
**Be careful, MAF Sensors are delicate and sensitive. Handle them with care.

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Time: 15-20 minutes
Tools needed: Screw Driver, can of CRC Electronics Cleaner, cloth and/or rag.

MAF sensors, after a while, tend to have a dirt film built up. I usually clean them every 30K miles or about once a year.

1. Pop open your hood and locate the MAF Sensors. There are two of them, located on either side of the engine. They are located on the tubing that connects the air intakes to the engine plenum.
2. First disconnect the MAF sensor from the cable. Gently push in on the little ridges to unseat the cable, and pull outwards.
3. Using a screw driver, unscrew the MAF sensor from the housing. **Note** be careful with these screws, they are small and very light. A misstep can result in a screw dropping into the engine bay.
4. Grip the MAF sensor ending, and gently pull outwards. Be careful with it since these are senstive.
5. Using the can of CRC spray, spray the metal wire looking components. One of them is fully exposed on the interior, the other is in a small indent on the inside.
6. Set the MAF Sensor on a rag and allow it to air dry.
7. When dry, re-install everything in reverse order. Then proceed to do the other sensor.
 

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Thanks for the detailed write-up and pictures!
 

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thanks. added to diy.
 

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What are the causes of dirty mad sensors on our cars? How could we know.
 

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Discussion Starter #5 (Edited)
What are the causes of dirty mad sensors on our cars? How could we know.
Air seepage, or the normal wear and tear of an air filter allowing bits of unfiltered air in with dirt particles that hit the sensor.

You'll notice a clean sensor has it's metal pieces relatively clean looking. Almost silvery/gray-ish. Over time, it will start to tarnish in color, with a slight film building on it. That's how you know.

Sometimes, and in the case of the e46 M3, certain errors (rough idle/stalling) are caused by a dirty MAF sensor.
 

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Any immediate/obvious performance benefit from cleaning it, or just preventing it from failing?
 

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Discussion Starter #7 (Edited)
Any immediate/obvious performance benefit from cleaning it, or just preventing it from failing?
With the e60 M5 I can't really say b/c I've cleaned them every 30K miles or so. It is more preventative maintenance, and like you said, prevent from failing.

When I had my e46 M3, I noticed better idle, and very slight (hardly noticeable) improvement in power/acceleration. I learned my lesson to clean them after my e46.
 

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Discussion Starter #9 (Edited)
/\

you're welcome!

I've learned a lot through M5board. Thought I should give back to the community :)

When I have the time, I plan on tackling some other things and make more DIYs.
 

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Discussion Starter #11
The spray doesn't seem to get enough of the grime off, would a cotton bud + spray be game over?
I've never tried that, maybe? I would think a q-tip should be harmless.
 

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Are both "springs" supposed to face the airbox? Took mine out and noticed that one spring is facing the airbox, the other one is not... Is that normal?
 

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Discussion Starter #13
Are both "springs" supposed to face the airbox? Took mine out and noticed that one spring is facing the airbox, the other one is not... Is that normal?
if i recall correctly, the indentation in the piece needs to be facing the direction of the on coming air flow. Hope that makes sense.

 

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Thanks! For quick reply! I have a problem disconnecting the wire off the sensor. It appears to be stuck. Any tips?
 

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Discussion Starter #15 (Edited)
the wire? you mean this connector below?

You have to press hard on the releases and just jiggle/wiggle it out.

 

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Thanks a lot for all your help! Just finished the cleaning and I must say that the car feels a bit more responsive. I do find it a tad jumpy, but I think that the ECU has to adjust to the timing because my MAFs have not been cleaned for 40k miles. I also have the Dinan intake (it came with the car) and I am not sure is the oil from the filters was effecting the MAFs. Anyway, how long does it take for the ECU to readjust? 100 miles or so?
 

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Discussion Starter #18
Thanks a lot for all your help! Just finished the cleaning and I must say that the car feels a bit more responsive. I do find it a tad jumpy, but I think that the ECU has to adjust to the timing because my MAFs have not been cleaned for 40k miles. I also have the Dinan intake (it came with the car) and I am not sure is the oil from the filters was effecting the MAFs. Anyway, how long does it take for the ECU to readjust? 100 miles or so?
I don't know. I haven't experienced that jumpy issue.
 

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Discussion Starter #19
Are MAFs considered a maintenance item? Thanks for the DIY!
Maintenance item by the dealer? No, don't think so. Not that I've seen or heard of. This is more of preventive Maintenance and cleaning the grime/dirt film that builds up on the sensor after a period of time.
 

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Thanks! For quick reply! I have a problem disconnecting the wire off the sensor. It appears to be stuck. Any tips?
You can do it without disconnecting the wire - I just did this weekend. It just makes removing the lower screw a bit more trick as there is a wire there. It isn't a problem, you just need to be careful not to lose the screw.
 
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