AFM vs. MAF vs. MAP - Air flow SENSORS - HOW they WORK and how they DIFFER from each other

[@d4a]

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[@FierceMotorworks]

Glad to see you getting sponsors and getting financial rewards for your amazing and incredibly helpful videos!

[@greekartvlog8712]

Where are you from? You sound and look like someone who grew up somewhere in northern Europe.

[@gawaynehackett6644]

@@FierceMotorworks aa

[@Cloakdasasin0]

Really love how you break down many of the finer points for enthusiast that a cursory internet search won't bring up.

[@mrzabie0138]

I worked in the electronics department for a leading auto parts remanufacturing company for many years, specifically on the mass airflow product line. I have experience with all these types of technology and can say that this guy gives a very accurate and comprehensive explanation of each type of device. This was well done!!!

[@NoahWL1]

The quality of your videos is always off the charts. Your explanations are excellent and the images and animations you show are super helpful. Thank you so much and keep up the amazing work!

[@theodoremarakas9899]

The chart would have to be as tall as the building I work for and it is 750ft tall. Simply impossible.

[@hjalmartorbjorn7523]

Yo, this is some serious gourmet shit. Love the abundance of information.

[@jasonanderson2876]

Well done sir💯👍🏼👌🏼, there are a lot of misconceptions out there.....thank you for the clarity, effort, & research that you put into these videos!!! Next video... correlation between O2 sensors and air meters to effectively correct air fuel mixture??🤞🏼🙏🏼

[@d4a]

O2 sensors will definitely be covered in detail in the future 😊👍

[@George.Andrews.]

Again fantastic. I have learned a lot In the last 2 hours watching your vids and nothing about them has pissed me off. No wazzup no excessive arm waving no annoying music or sounds no begging to be loved. Good speed good graphics good information good humour. Thanks again.

[@vintageaerodrome]

Great explanation! With so many "experts" on KZbin, it's nice to find someone who not only fully understands the subject but is an excellent teacher as well! Thank you!!!

[@steamdriver6964]

I got into the automotive industry after graduating a tech school in 91 and all you heard was oh these new cars with all that crap and today I can honestly look back and say it was the best thing that ever happened to the automobile I am no longer in the trade I left over 20 years ago best thing I ever did as it is not good well paying trade at least compared to what I'm in now but all the electronics in these vehicles today is honestly the best thing that could have happened

[@wiwidsetyo7086]

Hi, I am here in a developing country like your accent. Your English is clear to hear , so it is easy to understand the explanation. Before I was hard to understand the explanation from other channel because of the Europian accent which was unclear to hear for me. Thanks.

[@jimmcwhirter3798]

Awesome! I am a physicist, and I was looking for a "real" explanation of how MAF and MAP sensors work and until I found this, all I was finding was overly simplified (for what I wanted) explanations. And I got to learn about vane and vortex sensors as a bonus :-) Well done!

[@rickygomesz8973]

Damn right searching for a real explanation for a while

[@killer2600]

Very cool stuff, although I do think the temp sensor on MAF and MAP is necessary for accurate calculation. In the case of a MAF, whether air is cold or hot affects how it cools down a given object. As for MAP, the pressure combined with the temperature will give you the mass of a gas contained in a chamber of fixed and known size. As temperature decreases so does pressure so without measuring temperature you don't know if the mass has changed or if it's just a temperature change.

[@mojitocod]

Exactly what I thought! I would love an explanation as to why MAF and MAP sensors dont need temp sensor, if there is one

[@lastwithpaganblood87]

IAT sensor

[@davidcusick4739]

Agreed! PV = nRT

[@thomaseaton6142]

​@@mojitocodfor the MAF, cooler air is more dense (more air mass) and would cool down the hot wire more in the same way that simply have more less dense air flow would

[@kingstonzincfence]

You know when someone knows their stuff in how they make it so easy and enjoyable to watch. This is God given talent!! Thanks for sharing

[@d4a]

Thank you 😊

[@JazzbLu]

I've always had a general idea of how all of these air measuring devices work, but not the detail to which you descibe them in. I love your videos for this reason. Details details details! We all really appreciate you and you're knowledge! Thank you!

[@rampentpanda]

really liking these component breakdown videos! the knowledge is so arcane, so specific... i always think i know pretty much everything there is to know and then you come in and tell me there are two other completely different kinds of airflow meter that i have never heard of in my life!

[@hassanjibril6245]

I love the quality in the presentation, I dig the delivery, so much knowledge in under 20mins, you guys are amazing. Keep up the good work👍

[@neetones]

I taught for many years and now work in online learning. You are an EXCEPTIONAL teacher. Keep it up.

[@annaplojharova1400]

The reason why modern cars have both MAF and MAP is not the turbocharger, but the use of EGR. The ECU in fact does not need to know the mass of air, but mass of the oxygen in it. So when the engine intake takes just the air (so where we can rely on the ~20% oxygen content), the MAP is the most accurate (is not influenced by contamination, nor by any leak,...). This stays even when you would use a turbocharger. But once you start using EGR, the premise of the "20% oxygen" is not valid anymore, so although the MAP will still measure the mass of the gas entering the cylilders, it does not have any clue about the amount of oxygen there. In fact for determining the fuel dose, only the MAF is used. The MAP serves as the feedback sensor to control the EGR valve, so it dilutes the intake exactly how tye ECU asks for.

[@robertrocheville7769]

I agree with you mostly. Honda also uses the combo, mostly the MAP, to help detect Evap flow.

[@udovdh]

So a modern TDI, with ERG and MAF removed, can run fine with only MAP sensor measuring air?

[@robertrocheville7769]

@@udovdh If the manufacture wrote the software to compensate. They would probably kill power a bunch to be safe.

[@lanaya6261]

Yep, exactly. Older cars don't have MAP. Just MAF and they don't care about EGR opening/resulting pressure in the manifold. Also the O2 sensor becomes important here. It allows to even be more accurate on the fuel to inject.

[@petarmiletic997]

@@udovdh I don't know how modern you are thinking about, but if emmisions equipment is removed and ECU SW modified then yes. Early 2000-s no problem. For example Mercedes CDI used purely MAP-IAT strategy for their diesels until Euro 4 (2006), MAF's ONLY purpose there was to control EGR flow. A reduced fresh air mass means the EGR is working. That's why purely blocking EGR didn't work, the MAF would detect no decrease in fresh air flow and put you in limp mode

[@MichaelLBreton]

This channel is amazing. I learned more in a day about things I have always wondered about. You are a natural trainer and make your videos fun and informative. I'm going to be on this channel for a while. Helping me make informed decisions helps me actually get the danged STI built without tossing money in the pond.

[@doomned1234]

It's crazy how good your videos are. I've been watching ''mechanic'' videoa on youtube for years and you definitely produce the most clear and precise video. So glad I found your channel, keep up the good work!!

[@blyndrotor]

Have you seen the work on agent Jay Z. Very educational.

[@SuperCookieGaming_]

This was great. you explained how they work with such detail and simplicity that some teachers could learn a thing or two from you.

[@84gssteve]

Love the tech heavy episodes! My 89-91 RX-7 uses another (pretty rare) type of AFM, the sliding cone style. Its actually pretty aerodynamic since the airflow is smooth over the central cone and the entire unit is no bigger than a modern MAF. I think they were used by a few other makers, but Mazda seems to be the primary one. BTW, despite being 30 years old the FC engines use AFM, MAP and BARO pressure sensors.

[@jojoargento]

This video is AWESOME!!! Totally explains the technical differences between the various components and sensors (which I was having a hard time figuring out on my own), their functionality and purpose and also goes into detail to explain the physics behind how each one works. Very, very well done indeed. Also, I love the hand AIR flow demonstration... hilarious :D THANK YOU!

[@theodoremarakas9899]

I've been to automotive school and Mercedes school. NONE of them were able to explain this so well in 18 minutes by removing all the junk information and make technicians understand it effectively by simplifying the process. The gentleman is not only knowledgeable but also a great teacher. Knowing something and explaining it are two different trades and very few people can combine both. Excellent video. I wonder....58 people gave it thumbs down....what was in this video so wrong that contradicted their knowledge?

[@hemnamin2317]

If you want to understand how MAF and MAP work easily and clearly so you in a right place. Thanks to this very useful video.

[@MAJDSHWIKAN]

I love how you always pay attention to the smallest details

[@boomerguy9935]

Another fantastic explanation that is not "dumbed down", but explained logically for everyone to understand. I always love the visual aids.

[@tommygogh4243]

best channel of 2022 for real car guys who work on their own car

[@BB-zi5wi]

Hands down one of the best channels out there in this segment!!! Thank you guys, much love from Germany ❤

[@Slaktrax]

Great explanation. Cars ran speed density for a few years around 1990 relying on a simpler MAP sensor. I converted my own car to run a Custom Operating System speed density tune (with twin spark tables) and used it as a daily driver. It never missed a beat during the 10 years I owned it. (MAF sensor removed and P0102 turned off). It gave better throttle response and gained 15 rwhp on a back to back dyno test.

[@federicogioachini653]

Great videos!! I have just a small consideration: ECU is not measuring the resistance of the metal film of a HFM. It usually regulates (and measure) the current passing through the metallic film to keep it at constant temperature. Depending on this current, knowing the air temperature, it is possibile to calculate the air mass. The raw value will be then corrected by the ECU through a couple of maps

[@ghostofsparta6579]

I won't get this information and delivery quality not even in engineering universitys!! the history fun break down the ultimate informative way demonstration the radar maps & heat detecting monitor readings that you use .. god am speechless.. WE ARE BLESSED TO HAVE YOU IN OWER LIVES❤ 🙌 hail to the KING👑

[@rickygomesz8973]

Best explanation recommended thanks buddy 😀

[@kendalljohnston977]

Really appreciate the quality and thoroughness of this video! Thank you!

[@oleksiifilippov68]

Oh, best air animation ever (where “air” is written on the hand)! 🤣😅

[@mantatrip9319]

one finger was not enough. She told him 3 is enough.

[@heatseeka14]

2:07 I thought this was a kid friendly channel

[@chapa435ify]

Netflix: are you still watching? Someone's daughter: 2:07

[@jameshaulenbeek5931]

Kids gotta learn some time!

[@joseramirez-hh2sw]

3 finger huh....

[@udovdh]

Sarcasm?

[@moffatk7948]

Yoh man, very informative, explained MAF and MAP in detail that most novice can comprehend, welldone keep up the good work👌👍

[@sahalin12345]

My E30 325e with LPG conversion use to have some occasional backfires, I remember glueing the VAF back together - happy days.

[@StrongFreeLovin]

6 mins in and with no hesitation I firstly sub then like. Incredibly well done narration, would love to see more videos like that on car systems. Cheers.

[@hashemmi24]

That was one of the most informative video on the subject.

[@jmer3536]

Man this is an extremely detailed and informative video. Excellent diagrams, animations and pics to illustrate your knowledge

[@benjaminchukwuma6744]

Thanks a lot, this video brought back memories of how I had to change the MAF on a C320 severally, was not experienced, mechanic said nothing about air filters. Much later, I noticed air filters were very bad and clip for locking engine cover which houses the filter onto the MAF casing was also missing...felt very bad. I am better educated now...👍🏾

[@jakubtrzpis2595]

perfect for a Sunday evening

[@LifenSantaBarbara]

Thanks for such a great explanation of the difference between the components and their methods of operation. I've been a master tech for 20 years and I've never heard it explained as well as you have done in this video.

[@osmargds]

Great explanation! You have the ability to make a complicated thing easy to understand. Love from Brazil!

[@Micksoffthings]

I leave this under every video I watched, it helps the algorithm...

[@bobsponge6609]

Thank you for doing these very informative videos. Finally someone who knows what he is talking about.

[@bonzo9303204406]

veeeeery veeeery helpful insight on air sensors, as i watch more of your content, the more i understand why things happen with my cars... And you do it in such a simple way, that everyone could get what, why and when its happening ! Thank you !

[@tojiroh]

Ha! I found this video after cleaning the soot-covered MAF on my 1997 Audi wagon (ahem, Avant). I knew Google was watching me! X-D

[@blkdna748]

Informative. Knowing the Working of these sensor helps in diagnosis.

[@twotone_ra6558]

Heck yeah new video right as I wake up!

[@PushyPawn]

4:36 You certainly know how to pleasure your AFM, that technique from going from 3 fingers to 4 is proven and reliable.

[@MikeMBMr]

Nice explanation. One small correction however. MAP systems, also called "speed density" systems, calculate the mass of air filling each piston on the intake stroke by calculating (or estimating) the density of the air entering the cylinder with and equation the uses the absolute pressure and temperature of the air in the manifold. This density is then multiplied by the swept volume of the cylinder (full stroke x piston area) and by the volumetric efficiency (VE) for the engine at the particular rpm the engine is running at to estimate the mass of air entering the cylinder per intake stroke (hence "speed"). The ECU then calculates the pulse width to deliver the correct amount of fuel to achieve the desired fuel to air ratio for that particular intake stroke. If it is a throttle body system it multiplies the amount of fuel needed for a single cylinder times the number of cylinders for the engine and injects this with a single set of injectors in the throttle body.

[@fascistpedant758]

Exactly!

[@davehallier8584]

I love your videos bud... so so informative and interesting and really helpful to an old seasoned mechanic like me. Who thinks this stuff up eh! This knowledge now helps me better understand modern cars, cuz I work on a lot of newer models I.e. 2000 to 2016 most often. Thanks, now subscribed!

[@ПИПАЕ36]

Odličan i poučan video, šteta je što ne vidim više naših komentara! Inače za pravilno funkcionisnje map senzora pogotovo pri izmenama djelova motora potreban je senzor temperature(teoretski). Praktično radi bez toga(znam dosta 1.9/2.4 Jtd/mjet motora kod kojih "tjuneri izbacuju maf zajedno sa temp senzorom" i uz to postavljaju map senzore sa većim mogućnostima mjerenja(4 Bar map i sl).

[@MrAndrius12]

I don't recall hearing about the AFM :D I guess you learn something new every day :D

[@Mario_Marques]

Afm, also called "vaf" or "lmm" in german

[@MrAndrius12]

@@Mario_Marques good to know :)

[@deankay4434]

Used in 1976 Nissan 280Z without dampener but with an adjustable clock spring. A covered screw allowed a by-pass cavity around the flapper, was used to provided to fine tune the A/F ratio across the entire 7,000 RPM range of this well balanced inline 6 cylinder using a 3 gas engine analyzer. They were so precise that they required no catalytic convertor as no excess of unburned hydrocarbons or carbon monoxide out the tailpipe. With a five speed stick you could reach a top speed of 142 MPH via a divorced differential and half-shaft to both rear wheels. Not only did I own one, but was a technician at the dealership. Regular gas was a minimum fuel requirement but I ran Premium fuel. Only vehicles produced after July of 1979 required unleaded fuel and a catalytic convertor including imports that still met emissions standards without at cat. The 1976 was a high end compression and slightly more aggressive camshaft. That changed in 1977, they very next year. Identified by a gear reduction starter, camshaft part number and pistons. Resulting in lower HP output. The next year, 1978, the service manager offered 5 cents extra for each of these new test, made available in 1974 by the “National Institute of Automotive Service Excellence” or NIASE. It was 8 categories, 8 tests, multiple choice and 60 questions each. Techs at dealers and some corner shops, are paid by “Flat Rate” which is based on manufactures warranty. In 1977 customers paid $24 per hour except for “C” labor or coupon like oil changes. This meant 40 cents per hour extra. I took and passed all 8 test. Later, the name was shortened to “ASE”, certifying that you had book knowledge but hands on, as some questions could not be answered correctly if had not actually preformed this auto service. I hope this gives you information that will help as the vane airflow meter was used by Ford into the late 80’s. ASE Master Tech-Retired

[@MrAndrius12]

@@deankay4434 that's a lot of info in 1 comment! :D Thanks.

[@bradcogan8588]

I love your educational videos. You always put things in an easy to understand way.

[@benhowe2087]

Thank you for the best explanation ever. In continuation of this subject. Most modern aftermarket fuel injection systems use the MAP sensor. It has been found that with high lift and large over lap camshafts used in racing engines that all of these sensors loose accuracy with large reversion values at idle and low engine speeds on engines with no cam timing control. Correct air fuel mixtures are then controlled by blending TPS sensor input with MAP sensor overriding MAP sensor at high overlap situations.

[@802Garage]

Wow that air hand is getting a little out of hand. Gonna make me act up. Amazing video as always my dude! One of the best automotive channels on KZbin for sure. You've really gone next level.

[@d4a]

Thank you so much my man! I'm a joke compared to what you did to tiktok tho 😉

[@802Garage]

@@d4a Hahaha not even. TikTok is fun, but KZbin is still the big leagues. Race you to 1M subs. ;) Thanks dude!

[@billybobjoe198]

I had a Porsche with LJet with the AFM style you described here. You went out of you way to describe a strange style of MAF that I've never even heard of, but didn't explain the widespread Kjet AFM. I've had a Lotus, Mercedes, and BMW with Kjet. Kjet is great.

[@WouterB76]

Finally found a channel that goes in dept on car technics, thx a lot!

[@vusindlovu8897]

Blasted my mind with such beautifully informative and fruitful session👌

[@נתןאוחיון-ת6פ]

Thx for the great video.. also I just ordered the Carly after watching you introducing it.

[@nandzanasafaris5238]

This is an amazing video. Explained in 20 minutes what others take years. Well done!!

[@fernandoanatomia]

Complete guide on air mass measurement in engines. Thank you!

[@biffaozzie2373]

Great video- I learned a lot. As an aside, my motorcycle (BMW) doesn’t have a maf, map or what have you. It uses a throttle position sensor and intake air temperature sensor (along with engine rpm) to estimate air flow. At least it does this when it’s “open loop”- when the throttle position is changing, At cruise it goes closed loop and uses the oxygen sensor to adjust fuel flow, to get the stoichiometric ratio.

[@pradeepmina8364]

You just cleared my 2 year confusion ❤❤❤ thanks a lot

[@plamenpetkov7132]

A little clarification on MAF sensors. They have two thermal sensors, one on the heater, another aside. Electronic control aims at maintaning a constant temperature difference between the heated and unheated temp sensor. Flow rate is evaluated based on the selected temp difference and consumed power by the heater. The use of two temp sensors eliminates the inaccuracy related to air temperature variation. In steady flow this sensor works quite well, but under rapidly changing flow rate may have dynamic errors.

[@ashishacharjee8018]

Your videos are very helpful n explanatory. They clear up lot of doubts n questions.....thanks

[@ramonruilopezv.9457]

Great video. Very thorough explanation of a very complicated topic. Chapeaux

[@jerico5660]

As always, some of the best automotive explanations on the internet ;)

[@timothyball3144]

Today I finally learned what mass is. And something about AMFs and FAMs or something like that. Thank you.

[@d4a]

😂

[@martinneumann7783]

Wonderful! Even though I only drive a Citroën C1, all the informations about engine tech is very interesting for me. Knowing my vehicle better means recognizing errors better and how to react on those. That's the reason I like this channel very much! Dankeschön! 🚗💛🚗

[@Fransenn]

since i replased my maf sensor on my saab 9-5 1999 a few months ago i have been wondering how it works. but i was to lazy to search how it worked but thanks to the amazing youtube recommendations! good video!

[@MikkoRantalainen]

VW TDI engines use both MAF and MAP sensors and their measurements must match or the ECU will cut down the power. They can only detect leaks in turbo boost pipes if both sensors work correctly because in that case MAF sensor will show all the air going to turbo but MAP sensor will see some of the air missing. Broken EGR valve can also mess the manifold pressure which is measured by MAP sensor.

[@GaurdianAzzar]

Another great video! I really appreciate how thorough your research is and how well organized your delivery is. Keep it up!

[@JP-ib2iz]

You're a brilliant teacher, well done ♡♡♡♡

[@kimaq7236]

I was waiting for this video. Finally!

[@riceburner4747]

Wow! ALOT different than the "ole" carburetors when I was in auto shop as a teenager. Very interesting! Thank u! Love "air" written on your hand, a great teaching tool. 😂👍🇺🇸

[@aussietaipan8700]

Mate, I love your channel and the knowledge you share. A great knowledge source for apprentice mechanics.

[@fascistpedant758]

If, as you say, the vane type sensor is sensitive to velocity and density then it is a MAF sensor. Manifold volume isn't used in MAF calculations. MAP and IAT are used in conjunction with engine speed to calculate MAF, usually referencing tables specific to the engine.

[@stevesloan6775]

So good dude! Love your work!! 🇦🇺🤜🏼🤛🏼🍀🍀🍀😎

[@JanMessersmith]

Great presentation, nice sense of humor. BRAVO!

[@abeda.aldisi5168]

Great explanation . Congratulations and thanks. Couldn't be better.

[@brendonthomas2555]

Dude, this was excellent! Thank you

[@DucatiPaso750]

You just gave me a clear understanding of these devices. 👍

[@gembox12]

Love your brief explanation 👍👍

[@codymoncrief8478]

The only guy on youtube that makes me smarter

[@andreatheflyer]

To be precise on the MAP sensor: air density is function of pressure and temperature so to estimate exactly the density, an intake temperature sensor is always needed. The main drawback of MAP sensor is that it can't detect airflow, so even if the calculation of density is correct, he doesn't know how much of this air is sucked into the cylinders, so the engine ECU must also rely on the TPS (throttle position sensor) and a "volumetric efficiency map" loaded into the firmware. All of this may be less precise than direct mass airflow measurement with the MAF sensor.

[@asharma9345]

Excellent video Brother. Keep it up. P.S love the technical, scientific and engineering parts covered by you. I am an engineer too.

[@chandrakantindapurkar8738]

Good knowledge in simple words definately clear doubt about Maf and Map sensors Thank you Sir,

[@TheRnwood]

Great breakdown of these devices. Thank you!!!!

[@Chrissurfs]

THANK YOUUUUUUUUU !!!! :) Subscribed

[@rishijai]

Fantastic video. I was looking for a channel like this.

[@3800S1]

When it comes to tuning MAP is the easiest to learn and easy to transition from NA to boost without having to learn anything you already know from NA tuning. That said, it's hard to find good quality 2 and 3 bar MAP sensors that aren't complete garbage but luckily there are some OEM ones that work the same as the common aftermarket types. Also one of the big advantages of MAP over the flow meter type sensor is it's a lot faster in response, only limited by the speed of sound where as vane type takes some time to swing open and hot wire takes time for the resistor to cool in response of air flow. MAF has PE functions built into the ECU program to estimate the amount of air rushed in on sudden throttle openings based on TPS movements while the dead band of the MAF passes. Although MAP also has a similar thing but called AE its not anywhere to the same extent, usually only a few ms of extra fuel injected.

[@ricosam3347]

Very informative and clearly explained. Thanks.

[@uptownsamcv]

one thing I learned is that it's best to hook up the waste gate hose after the intercooler near the throttle body. pressure drops after the intercooler and having the waste gate hose on the turbo itself doesn't compensate for the pressure drop that occurs in the intercooler.

[@SkywalkerTibor]

Your explanatios are worth gold

[@jozsefizsak]

Very interesting, useful and greatly appreciated. You're a prince, my good man.

[@alextepozteco3681]

Ughhh my L28ET with a stupid AFM its so inaccurate when you start raising the boost that's why I ended up changing to a megasquirt ecu