How-To: Cleaning MAF (Mass Air Flow) Sensor

[jkm311]

I snapped some photos when I recently cleaned the MAF sensor. I was surprised how different my engine performed afterward. It didn't work as hard. The most noticeable difference was the decrease in RPMs at idle (base engine). Before, it would idle around 1,000 when warmed up. Now it's around 700 RPM, and quieter. Also, performance improved, cruising in the 40-50 mph range. And, yes - I did a complete engine detail AFTER cleaning the MAF, so I apologize for the dirty items under the hood! Everything is clean and shiny now!Legal mumbo-jumbo: This how-to worked for me, but be very careful when handling parts in your engine. I am not responsible if anything "goes south," should you attempt this.Without further ado:First, disconnect the negative wiring from the car battery (uncovered wire). Then, locate the MAF sensor assembly, just to the left of the airbox. You'll see two screws at the top of the MAF. Unscrew these (making sure to not let them fall into the engine!), then carefully pull the assembly out of the air intake hose. Then, disconnect the wiring on the back of the assembly by pushing down on this tab, and carefully pulling it off the removed assembly:This is how everything should look thus, far:This is the assembly you should have removed:As you can see, the MAF sensor (tear-drop shaped piece) is grimy:To clean, place the assembly on its side on a piece of newspaper, towel, etc. and gently spray the sensor with an MAF sensor cleaner spray ($6-$7 at any auto parts store). I sprayed it on both sides, two or three times. The MAF sensor is extremely fragile, so handle it carefully when spraying. Also, try not to spray your skin. This stuff really dries up grease (on engine parts and hands!) quite quickly. I kept a cup of water around to rinse off my hands, in case of overspray:After allowing the spray to completely dry (five minutes should be plenty), you can see the MAF sensor is more shiny, with a dark-yellow hue:After ensuring the spray has completely dried, re-attach the assembly to the wiring (it makes a nice, re-assuring click). Then, slide the assembly back into the air hose, like so:Grab your two screws, and screw them back in. Once you are sure everything is re-installed correctly, re-connect the negative wiring back to the battery (you'll have to re-set your head unit clock!). Note: It is recommended to do this procedure a couple times a year, depending on your driving habits. I have a K&N drop-in filter, so due to the nature of oiling the filter, I will be doing this a few times a year. Also, it took my engine some driving around to get used to the increased performance I gained from doing this how-to. By the second day of driving, it really idled nicely, and accelerating very smoothly (I never noticed how it had decreased over the past year!). Enjoy!

[bodhi_tree777]

Good write-up. When I do this, I also spray down into the sensor housing (the piece that you pull out, not the hole that you pulled it out of). If you look down you can see (I believe) two little wiry bits, and if I'm not mistaken it's these that are the actual MAF (?). I think the teardrop shaped part is a temperature sensor (although it's early, that could be the other way around). Either way, you can use the cleaner to do both of them. I usually do this every other oil change. *edit* stole this from matrixowners.com, this is the sensor I was referring to:

[jkm311]

Nice add to the post! The funny part is, after I removed the assembly, I noticed that very same area and gave it a few sprays (before doing all this, I read on the Matrix site that people recommended spraying both areas, so I made sure I did). Sorry to mislead folks, if it's the other way around. I thought the sensor for the air would be in the direct line of fire, with the temp sensor being raised, with the whole "heat rises" notion.One word of caution when spraying that portion, though. Let it dry standing up, so as to be sure it has dried up after the 5 minutes. I found that if the spray collected in pockets, it did not dry very quickly at all!

[keithvibe]

I did this very thing today... don't do what i did though... I started off by disconecting the neg terminal.Then unscrewed the screws, then procedded to drop one of the screws down in to the engine bay... 20mins later I found it and retrieved it with a magnet.I cleaned the sensor, waited for it to dry and put it back in my cai..I then went about to working on something else checking that off my list of things to do.Only to have a problem when i went to start the car and move it out of the garage.Car started then stalled.Tried again same result. stupid me i forgot to connect the electrical connection to the MAF So I disconnect the negative terminal again plug in the maf connector. Put the neg terminal back on. Car started with out issue but threw a code. So I disconnected the negative terminal again to clear the code left it disconnected for 10mins. Reconnected it and started the car again. No code. took it for a ride no code still.

[Wolfman213]

Hmm... sounds just like a couple weeks ago when my radio lights weren't working. Don't you just love those epiphanies of "Oh, how about I reconnect everything I disconnected!?"On, topic, this will def be on my to do list for next weekend! Not sure if it's ever been cleaned

[ehoff121]

This worked great for me.Prior to this service, I used to get a lot of vibration at 40 m.p.h. when the next higher gear kicked in. Not sure if it was cleaning the MAF or just resetting the computer with the negative cable off for 10 mins., but the driving at 40 is now loads smoother.Thanks for the post!!

[jkm311]

Glad it helped! Amazing what 15 minutes and $7 can do.

[kevera]

This is just a temperature probe,not the actual meter for airThis is the important one to clean

[jkm311]

Yep, Bodhi Tree corrected that right after I posted. SPRAY IT ALL! WOO HOO!

[viper]

I was more interested in cleaning the connector plug, the sensor looked clean however sprayed it but I couldn't disconnect the plug from the sensor house no matter how hard I tried. The Vibe is 6 years old the plastic hardened or stiffened.Over the years repairing I found many connectors oxidized not only on the Vibe, other cars, industrial machinery. outdoor machinery those old-timer computers etc. In many case just cleaning and reseating a connector 'plug' would remedy an ailment.

[Flinst0ne]

Thank you for this, it was very helpful. Hopefully I won't be getting the check engine light P0171 code now.

[HORSESCO]

THANK YOU SOOOO MUCH... I did this, (and normally don't work on my own, don't trust myself but do things such as change the air filter etc) We will see how it goes now with gas mileage.. Wish me luck!

[jkm311]

Glad to do it. And don't get too discouraged when your engine performs and idles differently afterward. Because of the battery disconnect and cleaning, your Vibe has to re-learn a few things! I'll be doing this again in the spring, when things warm up.

[HORSESCO]

Actually mine started right up and no different issues such as idling or the like... hoping for better mpg's tho... thats why I did it-well and figuring it needed it... I got the vibe due to my long commute (140 round trip 3-4x a week) and subie only gets about 23mpg.. vibe was getting 29 hwy before cleaning.. so lets hope that goes up to about 30-31, otherwise one will have to be sold and got the subie for the bad roads we (usually but haven't had lately) roads here in colorado. I also added lucas fuel system cleaner and all fluids have been changed/serpentine and plugs/air filters..also new tires..How often should the MAF be cleaned?

[bodhi_tree777]

Quote, originally posted by HORSESCO »How often should the MAF be cleaned?I do it every 3-4 oil changes. Gives you something to do while those last few drops are dripping out

[jkm311]

Considering I have the drop-in K&N filter (which is pretty easy to over-oil), I will end up doing this a couple times a year. I also suppose it depends on the air quality where you drive the most. I don't think it was a coincidence that I threw a CEL the first week it was somewhat "hot and humid," here in Michigan last summer. That oil was just WAITING to junk that thing up! Anybody that uses the standard paper-fiber filter might be able to get away with doing this one a year or every other, perhaps? I am destined to do this twice a year, I'm sure.

[HORSESCO]

I will stick with the paper air filter since this is my commuter car... already seeing a noticeable difference in gas mileage in a great way! Could be the MAF cleaning and/or the lucas fuel treatment, either way cool! I don't do my own oil but I can do the MAF cleaning 2x a year for sure!

[armandjones82]

That was a good write up in cleaning in the Mass Air Flow Sensor of a car. I have been trying hard to do that to really clean it properly. Now with your photos and explanation, I was able to understand more quickly how to do it. Great work and keep it up. Thanks for this one!

[ponta2147]

This is something else I should do, maybe it will help my mysterious disappearing gas mileage I posted in the other thread.

[jkm311]

Michelle, did you notice the drop BEFORE putting the CAI on? Seeing that you have a relatively new Vibe and only recently swapped in the intake, I'm curious as to why the MPG went down. How many MPGs are we talking? Do you mean highway, or mixed driving?

[ponta2147]

Yeah, I noticed the drop a few weeks before the intake, about 3mpgs on both highway and mixed driving. Adding the intake did not affect the mpgs either way. I was attributing it to using the AC more frequently, especially since I got about 3mpg less that Carrie on the way out to Indy when I was in a caravan with her, and the only difference was that I used the AC (on low). But then some other '09 vibers said they got mpgs in the 30s even with the AC on, so who knows.I'm just using some "quasi-scientific" methods here to see if there is a problem with the car, or just with my driving. I just worry since even though I got the car new, it already had 800 miles on it from the dealers shipping it around, I have no clue what they did to it for those miles. But ANYWAY what I did now is just put in some good fuel and added fuel injector cleaner, see if that makes a difference. Next tank I'm going to clean the MAF sensor, see if that makes a difference. If I do mostly hwy driving I'll compare to my hwy numbers, if I do mostly mixed I'll compare to my mixed numbers. If none of those things make a difference, it must just be me, or the AC and I won't worry about it anymore until the weather gets cooler. I know my tire pressure is fine.

[Wolfman213]

*edit* This posted right after your post before I read your mpgs dropped prior.*cough* lead foot *cough* I know for me, it was easier for the Vibe to breath and therefore higher speeds were easier to achieve and didn't feel as much of a strain on thing. I then notice a lower mpg. When I drive "normal" mine increased. But that is just my particular case, your's could be the MAF or something else.

[jkm311]

Quote, originally posted by Wolfman213 »*cough* lead foot *cough* Bwaaaa-hahahahahaha!Quote, originally posted by Wolfman213 »*edit* This posted right after your post before I read your mpgs dropped prior.As if said lead foot didn't exist prior...

[ponta2147]

Well, my first thought was my driving speed, but I've been driving my Vibe the same the whole time really (aka, always quickly, always at the top end of the speed limits or a little over) so I don't know why the mpgs would have suddenly dropped. I expected them to be lower the tank after I installed the intake because I *was* flooring it more often (partly to test it, partly because it was awesome) but they weren't really much different, and they didn't go back up again.I was also very disappointed in my numbers coming back from Indy, as I was making a conscious effort to stay on the cruise and not excessively accelerate. Didn't even hit 28mpgs. I'm just trying to rule out other things before I conclude it's just driver error!

[KNINE]

Why is it necessary to disconnect the negative terminal?

[jkm311]

My understanding was:Dealing with anything electrical, disconnect the negative. More likely:The system has learned the quality of the air, up to the point where you decide to clean the MAF. By cleaning it and NOT resetting the system (by way of battery disconnect) it will struggle and you'll throw codes. In theory, by resetting everything, the system learns the air quality with a clean MAF a lot easier.

[FaithHopeLove]

Just wanted to let everyone know...I finally got enough of gumption to do this procedure...and am I glad I did!!! I followed the procedure just as explained and when I took the unit out, it looked exactly like the bulb in the picture...DIRTY and GRIMY, totally, on one side...the other side was a little bit grimy. Gently handled it and sprayed it with a high quality carb & choke cleaner (Valvoline), that was recommended to me by A&A Auto Parts store nearby. It sprayed VERY clean, dried almost instantly, let it sit a few minutes, reconnected everything, double-checked...then started her up...set the clock on the dash...idled it a minute or two and drove off for a short ride at various speeds. As it started, I noticed it idled at a bit higher RPM...as I pulled out, I noticed an almost INSTANT DIFFERENCE in response and sensitivity in performance...am I glad I finally did this...it literally took about 10 minutes, if you take your time. Thanks folks...as the weather breaks in the next few weeks (hopefully), I'm sure I'll realize better performance and fuel mileage...Thanks again.

[A Psycho Martyr]

I may try this too, since my idle is so weird now with my CAI

[vibenvy]

I am planning on cleaning our MAF sensors when I next change our oil, so today I thought I'd disconnect the negative battery terminal and remove the MAF sensor to get an idea of what it looked like. Ours look nothing like the pictures jkm311 posted. Instead of the little "teardrop", ours have a flat "chip" looking piece. And I think I found the part that kevera posted is more important to clean, but I'm not sure since ours look so different . Unfortunately I couldn't get very clear, decent pictures with my little point-n-shoot camera, but here are the two pictures I took anyway:Perhaps someone can give me some insight on whether it would be safe to clean the "chip" part or not.

[Oskeewowow]

I just wanted to say that I'm new to this forum and am by no means a serious motorhead. I am trying to learn more about do it yourself projects. I'd like to thank the OP and all that have added insights here. I followed the instructions step by step and now have a smoother running 03 GT. Thank you all for your help. The pictures were awesome! Keep threads like this coming!!!

[vibenvy]

I cleaned our MAF/IAT sensors today. I picked up a can of CRC QD Electronic Cleaner at Walmart for less then $5.00.After doing a little more research online about cleaning the MAF sensor, I discovered the two most important things to look for in a cleaner are "quick drying" and "leaves no residue", both of which are stated right on the can of the CRC QD Electronic Cleaner . I haven't actually driven the Vibes yet, but I did start them up and they did seem to idle smoother. We'll see when I actually drive them and I am hoping to see at least a slight increase in our gas mileage.Quote, originally posted by J_TO_ENVY »I am planning on cleaning our MAF sensors when I next change our oil, so today I thought I'd disconnect the negative battery terminal and remove the MAF sensor to get an idea of what it looked like. Ours look nothing like the pictures jkm311 posted. Instead of the little "teardrop", ours have a flat "chip" looking piece. And I think I found the part that kevera posted is more important to clean, but I'm not sure since ours look so different . Unfortunately I couldn't get very clear, decent pictures with my little point-n-shoot camera, but here are the two pictures I took anyway:Perhaps someone can give me some insight on whether it would be safe to clean the "chip" part or not.After looking at the (what I was referring to as a) "chip" part again today I realized it's not a chip at all. It's actually two prongs with a wire between them and in the middle of the wire is what appears to be a tiny bit of glass (like the teardrop in jkm311's pictures), so essentially it's the same thing just a completely different shape, look, etc. I sprayed that a couple times with the cleaner and I made sure to spray the part that kevera said is most important as well. Everything turned out great. No warning lights, rough idle, etc. so I eased my own fears and thought I'd share with my fellow '09-'10 2.4L owners .

[star_deceiver]

Here's my 2 cents:I used Gunk Mass Air Flow Cleaner from Cambodian tire, $8.It idles a little quieter now. We'll see if there's any difference in fuel economy... got a full tank after I cleaned it, we shall see.

[CAMOGIRL]

Quote, originally posted by J_TO_ENVY »I cleaned our MAF/IAT sensors today. I picked up a can of CRC QD Electronic Cleaner at Walmart for less then $5.00. I grabbed this tonight because I think I'm going to do this tomorrow. It didn't come with a straw...would you recommend using one or not? I can surely find one tomorrow at the hardware store. I'm excited about my first real under the hood endeavor!

[CAMOGIRL]

DID IT! My Vibe used to idle around 2k right after start up and never calm down... it worried me a bit. It also sounded a little rough, and I'd get a little bit of a hot exhaust smell if I romped the car around town.... all of the above has been cured with a little spray! I DID have to put the whole assembly back on and screw it down in order to pull the electronics plug off, I have poor strength in my fingers due to CTS and I had to use both hands to tug it off and hold the clip at the same time.Happy MAF:Happy Vibe:Proud of myself on this one Tomorrow my sister and I are tackling her spark plugs.

[csxt8058]

Nice job!! I'm liking your outside temp. display a whole lot more than the temps. here right now. JR

[vibenvy]

Quote, originally posted by CAMOGIRL »I grabbed this tonight because I think I'm going to do this tomorrow. It didn't come with a straw...would you recommend using one or not? I can surely find one tomorrow at the hardware store. I'm excited about my first real under the hood endeavor!DID IT! My Vibe used to idle around 2k right after start up and never calm down... it worried me a bit. It also sounded a little rough, and I'd get a little bit of a hot exhaust smell if I romped the car around town.... all of the above has been cured with a little spray! I DID have to put the whole assembly back on and screw it down in order to pull the electronics plug off, I have poor strength in my fingers due to CTS and I had to use both hands to tug it off and hold the clip at the same time.Mine came with a straw but for some strange reason I couldn't get it to stay in the hole on the can. The straw seemed too small for the hole . I ended up just holding the sensor a little ways away from the can and spraying it without the defective straw. Congratulations on successfully completing your first under-hood endeavor ! Glad to hear your Vibe is happy as well !

[CAMOGIRL]

I went to the parts store today and he just ripped one off a can of a nother CRC product. It fit tough but worked! I was glad I had the straw.

[Beer Belly]

I recently noticed my gas mileage has decreased and the car has been a little sluggish. I think cleaning the MAF sensor will be the first thing I try. Any other suggestions that may help? It's a 2007 and at close to 93,000km. Have done oil changes ritually every 5,000 to 6,000km and am pretty much due to replace the transmission fluid.

[vibenvy]

Quote, originally posted by Beer Belly »I recently noticed my gas mileage has decreased and the car has been a little sluggish. I think cleaning the MAF sensor will be the first thing I try. Any other suggestions that may help? It's a 2007 and at close to 93,000km. Have done oil changes ritually every 5,000 to 6,000km and am pretty much due to replace the transmission fluid.I'm willing to bet just cleaning the MAF sensor will make a very noticeable improvement .

[06pvibe]

Set your point and shoot to MACROS on next time and those close-ups will be clear.

[jkm311]

Did the procedure again, right before a 780-mile car trip this weekend. And man, am I glad I did. The Vibe wasn't down-shifting on slight inclines with cruise engaged (even with the AC on), and I generally enjoyed better performance at various speeds/conditions.However...I'm wondering if cleaning the MAF really had anything to do with the gains. I say this because when I pulled my MAF out, it looked to be much cleaner than when I wrote this how-to. The amber temp "bulb" was shiny, and the thin wires up into the actual MAF looked shiny as well. Not dull with residue. I think this has a lot to do with me getting better at cleaning and re-oiling my K&N drop-in filter.Could just disconnecting the negative on the battery and re-setting the ECU produce the same results (with a clean MAF)? Hmmm...No matter what, the lower RPMs at all times = smoother ride, and most likely a few less drops of gas used up.

[Beer Belly]

Cleaned the MAF this weekend, haven't really noticed a difference in performance as of yet. Maybe on a long trip it will be more noticeable in the wallet.

[rAERRK]

finally got around to doing this and i definitely notice a difference. idle has dropped well below 1k while stopped, transition between shifts seems smoother, and the kick from lift is more noticeable now obligatory pic

Attached files

[jasonvibe]

OK, since October I have had poor idle after fully warm YET when the air temp is below 45F..SHe used to idle very smooth. Using the OEM Matrix Manual trouble shooting...I have been around the moon changing intake gaskets, checked fuel pressure , valve clearances and changed spark plugs. Everything so far checks good. COULD THIS BE the Magic cure. Ground wire disconnect- I guess So it relearns new perameters?? Also , couldn't I clean this by simply removing the Air cleaner top and use a few careful squirts??? well IT'S EITHER this MAF, the ISC (IDLE SPEED CONTROL VALVE) OR THE DAMN emissions plumbing UNDER THE CAR. The guy at autozone did not think it will help because I have the standard paper air filter. What do you guys think??? should I try this soon? I have 70kmiles

[rAERRK]

Quote, originally posted by jasonvibe »OK, since October I have had poor idle after fully warm .SHe used to idle very smooth. Using the OEM Matrix Manual trouble shooting...I have been around the moon changing intake gaskets, checked fuel pressure , valve clearances and changed spark plugs. Everything so far checks good. COULD THIS BE the Magic cure. Ground wire disconnect- I guess So it relearns new perameters?? Also , couldn't I clean this by simply removing the Air cleaner top and use a few careful squirts??? well IT'S EITHER this MAF, the ISC (IDLE SPEED CONTROL VALVE) OR THE DAMN emissions plumbing UNDER THE CAR. The guy at autozone did not think it will help because I have the standard paper air filter. What do you guys think??? should I try this soon? I have 70kmileshave you ever used sea foam?

[jasonvibe]

Yes, I have used Seafoam. Having soaked carbs in Seafoam. It is simply a detergent, like WD40. It does NOT break down varnish typically in a carb or fuel system. You will get the same results pouring WD40 or Kerosene into your fuel.I have nothing good to say about it. I think it's snake oil. I use Techron or Berryman's . Both really work...I used Seafoam, Berrymans and Techron when this started. The Seafoam was laying around from another job I bought it for motorcylce carb cleaning. Useless.. So I emptied it. Techron and Beryman's actually can see it desolve the bad crud. Seafoam...nothing happens. Seeing is believing

[rAERRK]

well its worked for me and plenty of other people

[jasonvibe]

I am not saying it does nothing. It's just not as good as many other items around. I did tests with Seafoam. It really is just a detergent. And with fuel systems a SOLVENT is what is really needed. At least it helped you.

[jasonvibe]

I cleaned it with the CRC "QD" stuff. For what it is worth. I believe it runs better. Seems to idle better, smoother too. And the rough idle has been the main problem when air temps are cold. But now it's almost summer and cold days are behind. But, I still have other things to check. So, I guess next tank of gas may be be the overall proof. I was also thinking of getting an OEM Denso air filter. I was told by a mechanic , "some cars are sensitive to what brand air filter is used." And these small 4 cyl. engines can be just that, sensitive. Also, I did change the air filter last year. Though it's still paper type. 2 things I noticed. (1) reinstalling the MAF...worry about the wire to it last. I would hate for someone to hold the MAF in mid-air and DOAH...drop it trying to connect the plug. (2) warm idle in "N" or "P" should be one click below 1000rpm...I think that's 750. And in gear just under that, maybe 650

[A Psycho Martyr]

bump