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View Poll Results: How often do you clean your MAF sensor?
Once a month or more 22 3.37%
When i change my oil 91 13.96%
When it needs it, I can tell by my EM or my butt dyno 158 24.23%
NevAR 384 58.90%
Multiple Choice Poll. Voters: 652. You may not vote on this poll

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Old 06-07-2006, 07:40 PM   #26
modaddict
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Quote:
Originally Posted by Phil Jr.
ok i popped out my maf and it looked clean as a whistle, as in brand new. ANyone got a pic of a dirty one??
I dont think you can actually see the MAF wires, but you can see the IAT probe. If your IAT probe is dirty....chances are your MAF wires are dirty. I bought a used perrin short ram off ebay last year, and it came w/ a MAF sensor. I took it out and looked at it and it was EXTREMELY dirty (on the IAT probe). I now have a used MAF for a spare, and i used the one that came off my car when i put the intake on. But this just confirms that many people dont clean their sensors. I wish i could have taken a 'before and after' readings of the MAF at WOT to compare.
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Old 06-07-2006, 07:44 PM   #27
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Quote:
Originally Posted by nhluhr
knowing that it takes at least a couple days for the trims to normalize to where they need to be, you should definitely reset the ECU when cleaning, especially if you plan to be getting tuned the next day, driving hard, track day, etc...
You've just suggested it's a good idea to reset you're ECU the day before it gets tuned or used on a race course. That's bad advice. After you clean the MAF and reset the ECU, the ECU is likely (as in 99.9% of the time) to eventually learn essentially the same long term fuel trim (LTFT) that it had before the MAF cleaning. And the larger the LTFT is in magnitude, the longer the re-learning takes.
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Old 06-07-2006, 08:16 PM   #28
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Quote:
Originally Posted by Evil STI
Why play devil's advocate when a 10 second reset 'wipes the slate clean'?

The ECU doesn't learn within seconds. It takes a minimum of four key cycles for it to maximize effeciency and/or power output.
How long does knock correction take? The engine just knocks away until it feels like correcting it?
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Old 06-07-2006, 08:45 PM   #29
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Quote:
Originally Posted by silver arrow
How long does knock correction take? The engine just knocks away until it feels like correcting it?
completely different topic. Knock correction is an instaneous thing that happens in response to detected knock and corrections linger for awhile until the ECU feels it can push it back again.

With AF Learned Trims, that is not something that can just be corrected immediately because it is so much more variable, thanks to effects from tip-in and lift-off. The ECU makes instantaneous corrections to AF in closed loop and then remembers a running average so to speak of those corrections for every single MAFv it has encountered and starts to modify the learned values.

The reason it's better to reset the ECU when this takes place is because resetting the ECU also takes the IAM back to the standard initial value of 0.5 (unless you or your tuner has changed it) which means you're not running full advance during this afr-uncertain time.

Also, experience has shown that Learned corrections which are made in closed loop DO get applied to open loop as well, but the mechanism by which that happens is not clear to me yet. A lot depends on the MAF sensor and the stored corrections so again... why chance it when you can just play it safe?
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Old 06-07-2006, 08:54 PM   #30
Phil Jr.
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how can we tell is the IAT probe is dirty, I mean the plastic casing which my holds the MAF looks brand new, not dirty at all. The IAT probe just looks darkish brown, should be it like yellow?
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Old 06-07-2006, 09:02 PM   #31
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it should be shiny so that you can easily see the glint of light off it and the deep red/orange color within.

The MAF wires you CAN see if you get the angle just right... they're way up in there.
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Old 06-07-2006, 09:05 PM   #32
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so sloshing it around in some 90% rubbing alcohol should do the trick right? can I wipe the IAT probe?
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Old 06-07-2006, 09:17 PM   #33
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Quote:
Originally Posted by nhluhr
completely different topic. Knock correction is an instaneous thing that happens in response to detected knock and corrections linger for awhile until the ECU feels it can push it back again.

With AF Learned Trims, that is not something that can just be corrected immediately because it is so much more variable, thanks to effects from tip-in and lift-off. The ECU makes instantaneous corrections to AF in closed loop and then remembers a running average so to speak of those corrections for every single MAFv it has encountered and starts to modify the learned values.

The reason it's better to reset the ECU when this takes place is because resetting the ECU also takes the IAM back to the standard initial value of 0.5 (unless you or your tuner has changed it) which means you're not running full advance during this afr-uncertain time.

Also, experience has shown that Learned corrections which are made in closed loop DO get applied to open loop as well, but the mechanism by which that happens is not clear to me yet. A lot depends on the MAF sensor and the stored corrections so again... why chance it when you can just play it safe?
I still think you are way over estimating the change made by cleaning the MAF as far as worrying about the car's AF ratio. I would like to see one of the tuners from the board weigh in on this. Again the car will protect itself instantly with knock correction and will make the minor adjustments needed.
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Old 06-08-2006, 03:58 AM   #34
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How much does a maf go for these days?
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Old 07-03-2006, 04:38 AM   #35
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i just stumbled across this thread and it got me worried that my maf is dirty, its been 39000 miles and i dont know if they cleaned it yet, do dealerships clean them everytime you get an oil change? (subaru), and if i do it myself(newbie) what shall i do first?
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Old 07-03-2006, 04:40 AM   #36
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No, the dealerships will probably never clean it. Just go to any autoparts store, buy a can of CRC brand "QD Electronic Cleaner" or CRC "MAF sensor cleaner" (they are identical products with different names and prices), then unplug/unscrew your sensor, spray the stuff up inside the tube at an angle so you're not hitting it directly, let dry, reinstall, be happy.
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Old 07-03-2006, 10:05 AM   #37
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Quote:
Originally Posted by nhluhr
check the ingredients on brakleen. It is definitely NOT the same and not very safe for the plastic and rubber on the maf sensor.
Carb cleaner eats plastic and rubber. Brakeclean is safe for plastics. Ask a mechanic.
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Old 07-03-2006, 10:56 AM   #38
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i have never cleaned mine
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Old 07-03-2006, 03:49 PM   #39
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Cleaned mine... mine was filthy after 15k miles. Yes I'm using K&N Typhoon. Just purchased CRC can and sprayed it... take seconds and it's now sparkling clean. I didn't reset my ECU, but I'm gonna do that after I clean my K&N Filter as well.


It won't hurt you as long as you are careful with it. I felt less hesitation and felt smoother idle after I cleaned it. Mine was BLACK on one side.
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Old 07-03-2006, 03:52 PM   #40
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Quote:
Originally Posted by sizzflair
Mine was BLACK on one side.
You realize the part you can see is not the MAF right? That's just the temperature probe. The MAF is actually a tiny little wire up inside the tube of the plastic body. You can just barely see it if you look up in there with the lighting just right.

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Old 07-03-2006, 05:45 PM   #41
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Wow good thread,60K never cleaned,do all my own work.OK
here it goes were the hell is that MAF,is it on the tube going to my airbox?? Just went down and looked,not sure.Hey I did my own clutch so I am that bad of a noob!!
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Old 07-03-2006, 06:43 PM   #42
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This should answer your questions:






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Old 07-03-2006, 06:43 PM   #43
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Last edited by nhluhr; 05-11-2008 at 07:05 PM.
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Old 07-03-2006, 06:53 PM   #44
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Yeaaaa i think ill do this when i get home as its not been done for the past ..........29K miles..... FLAME SUIT ON
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Old 07-03-2006, 06:56 PM   #45
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Very good.
Save thread in wrx file. 2.5 Axis SB W/ Perrin big maf.
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Old 07-03-2006, 07:01 PM   #46
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FAQ sticky material.

I never knew.
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Old 07-03-2006, 07:08 PM   #47
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yea I made sure that i sprayed that inside too.

woot!
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Old 07-03-2006, 08:19 PM   #48
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sure glad i started this thread. thanks nhluhr and if anyone asks anymore questions on how to.....



....they need to be shot.

Happy cleaning everybody!
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Old 07-04-2006, 10:14 PM   #49
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Major props to nhluhr , I decided to check mine as well, I've got 25K miles on my stage II STi (with an APS CAI) and sure enough the IAT side facing the intake was charcoal black, cleaned it with QD Electronics Cleaner as well as the rest of the sensor, put it back in and WOW what a difference it made!! I no longer have a slight hesitation and it idles so much smoother
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Old 07-04-2006, 10:55 PM   #50
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I was under the assumption that upon shut down, MAF wires heat up to some insane temp to burn off any contaminants. Is this not correct?
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