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Old 06-17-2014, 10:45 AM   #26
joewrx628
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Ok so if my car was speed density tuned with the map sensor would cleaning the MAF do anything?
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Old 06-17-2014, 10:54 AM   #27
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Quote:
Originally Posted by joewrx628 View Post
Ok so if my car was speed density tuned with the map sensor would cleaning the MAF do anything?
The answer you did not already read
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But I'm running a speed density tune, should I care about my MAF? Nope. The only thing you really care about is the matchhead thingy that does the temperature (which isn't a huge deal) and some cars run an aftermarket version of this, so if you are speed density, you just wasted 5 minutes of your life!
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Old 06-17-2014, 12:13 PM   #28
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Some cars ignore MAF readings at WOT, from this I assume that Subarus don't?
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Old 06-17-2014, 12:32 PM   #29
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Lots of people mistakenly think the IAT probe (exposed part) is the only part they should clean. If you look through the bottom of the MAF you'll see 1 or 2 wires which are what you really need to clean.
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Old 06-17-2014, 12:44 PM   #30
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I just ran into this the other day. Car ran lean, cleaned the MAF, car runs better. Subaru, are you listening? Verifying the MAF signal is SUPER SIMPLE. You already have intake air temp, intake pressure, and volumetric flow rate from engine RPM. A simple heads up via engine light telling us the MAF is out of spec would be a HUGE help. K?

BTW, this is one way to check your MAF, if you log those values, you can calculate mass air flow. My MAF was off by a factor of 3 it was so dirty. At 180g/s, it was reading only 60g/s.
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Old 07-09-2014, 12:05 PM   #31
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Quote:
Originally Posted by DougNuts View Post
Some cars ignore MAF readings at WOT, from this I assume that Subarus don't?
Correct. They never ignore the MAF.
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Old 07-09-2014, 12:16 PM   #32
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Ron,
thanks for putting my stuff out there for everyone.

I'd like to take this opportunity to educate people a little more on this.

Just how bad is it?
VERY VERY BAD. AFR is not the only thing affected by low MAF voltage. Engine load is calculated off the MAF. Engine load is the x-axis for all the fuel and timing maps. When a MAF deteriorates and voltage drops, indicated and calculated load drop. Not only does this mean the AFR target is leaner, it also means that the timing is much more aggressive.
For many, the first indication of a deteriorating MAF is a blown motor (rod bearing, burnt valves or busted piston).

Why doesn't Subaru compensate for this?
They do. However, a tune, (by any tuner) eliminates the protective margin that subaru puts in the ecu. Ever wonder why the cars are nearly 15% too rich on the top end? Ever wonder why the "System too lean" check engine light is triggered at 15%?
DING DING DING, we have a winner.

Since the 16bit ecu only has so much bandwidth available for processing and controlling engine parameters, a "plausibility" table used to check MAF readings in relation to RPM and boost was not able to be used. So to cover MAF deterioration, they make the engines run very rich under open loop. Many EJ205's in stock form run with AFR's near the 9's at WOT. The quickest way to pick up power is too lean it out up top to a more appropriate AFR. By doing that you eliminate the 15% buffer that Subaru put in the programming. Under factory tuning, as the closed loop trim gets to 15% a CEL is triggered to initiate a troubleshooting process to get you to fix the issue.

So save yourself an engine build and replace your MAF at 100k or 6 years whether you think it needs it or not. It's also a good idea to replace your knock sensor. Use only OEM Subaru knock sensors and only OEM or Denso MAFs.
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Old 07-09-2014, 12:57 PM   #33
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Thanks for the feedback...I hope to update this soon, then send to 2.0 then to 2.5 forums for a bit of advertisement then memorialize in teh manifesto.

parts.subaru.com SENSOR ASSEMBLY-KNOCK $119 MSRP: bookmark for update

Last edited by Unabomber; 07-09-2014 at 01:05 PM.
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Old 07-09-2014, 01:53 PM   #34
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... And this is why my tuner recommended cleaning my MAF sensor during every oil change. Is it overkill? Probably. But it takes 2 minutes, kills the time while the oil drains, and a can of MAF cleaner seems to last forever. So why not?


Solid information. Thanks!
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Old 07-09-2014, 02:04 PM   #35
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Just added a new MAF to my build spreadsheet. Thanks for the solid advice!
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Old 07-09-2014, 02:37 PM   #36
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Is search function broken still?
I'm pretty sure we covered all this back in 2002-3, but if not, then good sticky!

OOps looks like this has already been covered, OP please use search function in the future please.... :P

http://forums.nasioc.com/forums/show...ensor+cleaning
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Old 07-09-2014, 02:44 PM   #37
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there was no data in that thread. Also, that car was not 5 or more years old either.

Also, while you may consider it "covered" already, it has not gotten around enough in the last 12 years. We see engine failure from bad MAF sensors almost weekly.

So instead of using your post and energy in bagging on Ron, maybe you should use it to pass around such vital information.
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Old 07-09-2014, 03:23 PM   #38
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Great information. Will definitely be cleaning mine this weekend.
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Old 07-09-2014, 03:26 PM   #39
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Because of this, Denso stocks have skyrocketed and MAF shortages have begun.

Guys at part warehouses: "Someone from the interwebz must have told people to replace their MAFs".
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Old 07-09-2014, 04:49 PM   #40
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i've learned from my previous cars that cleaning this helped with various things including MPG...so i've always cleaned mines on a yearly basis...just spray away and use a Q-Tip to get any addition gunk off if needed...
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Old 07-09-2014, 08:42 PM   #41
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Quote:
Originally Posted by super_subie View Post
i've learned from my previous cars that cleaning this helped with various things including MPG...so i've always cleaned mines on a yearly basis...just spray away and use a Q-Tip to get any addition gunk off if needed...
DO NOT use a Q-tip, your finger, a foam swab, your cat's tongue, or ANY other object to clean ANY part of the MAF!!
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Old 07-09-2014, 09:09 PM   #42
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Good advice, but I'm surprised this wasn't common knowledge though.

I used to clean the MAF on my nissans regularly. At least once a year. That along with an ecu reset really wakes the motor up a bit.

Plan to do it on my STI annually too.
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Old 07-10-2014, 01:05 AM   #43
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Quote:
Originally Posted by Unabomber View Post

DO NOT use a Q-tip, your finger, a foam swab, your cat's tongue, or ANY other object to clean ANY part of the MAF!!
I've used this method for over 10 years never had a problem...though never on a Subaru, always on Toyota's n Honda's
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Old 07-10-2014, 07:30 AM   #44
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Quote:
Originally Posted by super_subie View Post
I've used this method for over 10 years never had a problem...though never on a Subaru, always on Toyota's n Honda's
The reason for that blanket, end all advice is that the MAF wire itself is a **** hair and depending on the age, even looking at it can cause it to break. If you put out that there is to be no mechanical cleaning whatsoever of the whole ding-dong MAF, perhaps that will stop that 1 in 100 person who reads this thinking if spray/drip dry is good, then wire brushing followed by media blasting and then hot tanking in sulfuric acid would be better. Never go full retard on the MAF....spray/5 minute drip dry/reinstall is the mantra.
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Old 07-10-2014, 10:45 AM   #45
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Quote:
Originally Posted by Unabomber View Post
The reason for that blanket, end all advice is that the MAF wire itself is a **** hair and depending on the age, even looking at it can cause it to break. If you put out that there is to be no mechanical cleaning whatsoever of the whole ding-dong MAF, perhaps that will stop that 1 in 100 person who reads this thinking if spray/drip dry is good, then wire brushing followed by media blasting and then hot tanking in sulfuric acid would be better. Never go full retard on the MAF....spray/5 minute drip dry/reinstall is the mantra.
I'm starting to doubt he's actually using a Q-Tip on the MAF. I think he's using it on the IAT portion. Post up the picture I sent you.
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Old 07-10-2014, 10:48 AM   #46
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Here see:

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Old 07-10-2014, 01:37 PM   #47
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Quote:
Originally Posted by MPS-Dom View Post
there was no data in that thread. Also, that car was not 5 or more years old either.

Also, while you may consider it "covered" already, it has not gotten around enough in the last 12 years. We see engine failure from bad MAF sensors almost weekly.

So instead of using your post and energy in bagging on Ron, maybe you should use it to pass around such vital information.
Detect sarcasm much? I think you left a tool in your computer room, you should place it back in the garage.

There is data in the 30 other threads related to MAF cleaning, there is data via links in the thread I linked.

Sorry cupcake, you lose. I know you think it's exiting to post old info like it is new, but it doesn't take a 5 year old car to develop a dirty MAF. We were seeing it early with the oiled air filters, so even new cars should be aware of cleaning their MAFs. I was being mainly sarcastic, because if someone came on here and posted a thread about cleaning MAFS they would have been told (most likely by the OP) to do a search.

Maybe you should spend more time and energy doing what you do and not defending someone elses thread. Ron's a big boy, he can handle himself.

Last edited by Giamilton; 07-10-2014 at 01:45 PM.
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Old 07-10-2014, 02:11 PM   #48
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Quote:
Originally Posted by Giamilton View Post

Detect sarcasm much? I think you left a tool in your computer room, you should place it back in the garage.

There is data in the 30 other threads related to MAF cleaning, there is data via links in the thread I linked.

Sorry cupcake, you lose. I know you think it's exiting to post old info like it is new, but it doesn't take a 5 year old car to develop a dirty MAF. We were seeing it early with the oiled air filters, so even new cars should be aware of cleaning their MAFs. I was being mainly sarcastic, because if someone came on here and posted a thread about cleaning MAFS they would have been told (most likely by the OP) to do a search.

Maybe you should spend more time and energy doing what you do and not defending someone elses thread. Ron's a big boy, he can handle himself.
Your comprehension is the one that needs work, fluff ball.

As I said, MAF sensors deteriorate over time. If you actually read all the information I posted and in this thread you would see that is the case. The dyno sheet posted was with a clean MAF that had deteriorated so much that it no longer provided proper voltage.

You can clean an old MAF all you want, it will still go bad and you'll still toast an engine.
Thus my five year old remark. The sensors that they were cleaning were only dirty, not deteriorated.

You owe me an apology.
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Old 07-10-2014, 10:45 PM   #49
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Quote:
Originally Posted by Unabomber View Post
parts.subaru.com SENSOR ASSEMBLY-KNOCK $119 MSRP: bookmark for update
I'm seeing (at parts.subaru.com) $270 and $190
*sad panda*

Amazon has Denso version $http://www.amazon.com/Denso-197-6040-Mass-Flow-Sensor/dp/B007WMG8A0
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Old 07-11-2014, 08:29 AM   #50
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The Knock Sensor part #22060AA160 is $119.95 at Ron's link. Appears to be same price for all models except the early B&MPI TURBO.
The MAF part #22680AA380 is $269.95
(quoting prices for MY2011)
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