Service Done Right #13: Mass Airflow Sensor Testing - Is The Sensor Lying To The ECM?

[@theadorephaedon1691]

I wish you taught classes for Automotive, I’ll sign up in a New York minute! Very informative. Thank you for your time and for your best knowledge.

[@FieldmouseMechanix]

Loved the video, I watched it three times to take notes and still don't know how you fit that much information into such a short video. Well done. I found the download link for the VE spreadsheet in the comments. It is definitely going in my diag computer!

[@petar443]

I've read an article from your collegue Scott Shotton how to modify the VE calculator and get accurate number on turbo engine. If one works on a turbo engine you just need to gather what the pressure in the intake is while doing the VE test run. You can either use factory MAP sensor if equipped or install pressure transducer. Collect the map sensor data in "psi" reading. Then multiply the reading by 2 in order to convert in "inHg". Then add the calculated number to the current barometric pressure(inHg), at the altitude the test drive was performed. Then input this final calculated number in the VE calculator "barometric pressure" input. Man i love MotorAge 👍🎸🔧🥃

[@orvilledanvers315]

I've read and watch your videos...they are very interesting and informative...I really learn a lot from these videos

[@TheLoneWolf_andCoyote]

Thank you pete for this educational tuning video it's amazing how one individual sensor can make or break you.

[@MotorAgeMagazine]

Glad it was helpful!

[@oldschool9746]

Thank you Pete for sharing your time and knowledge.

[@yupcrazy...5465]

Now that's a new one I've never heard or even considered diagnosing specific sensors in global OBD2 because of the difference in the data...

[@MotorAgeMagazine]

You can diagnose and repair 95% of problems related to drivability with Global OBD II

[@bigdzx6r]

thank you for the spreadsheets which i will be using it for TS (trouble shooting) my sister in law 2012 Camry 2.5L with MAF (Low input) P0102

[@deankay4434]

Great explanation of what is happening and what to look for. If you scanner cost less than $100, most likely your are seeing "Global PIDs" as required by law. Fun fact? This was a value test we rigged with a voltage drop on the ground side at GM training centers in 2002, but even more relevant today as fuel prices increase. And never forget engine wear, compression, intake leaks, timing chain stretch and incorrect tire size will change load values! Great video... DK, ASE master, retired.

[@MotorAgeMagazine]

Thank you!

[@thinman8621]

Good diagnostic. Thank you.

[@mfreiher]

Very informative. The link for the VE calculator isn't working. Thanks

[@bobwhite1734]

Does this work the same with diesels? Like gen 4 Ram 6.7L. being a diy, I am trying to gain all I can about my engine. thanks for sharing your information.

[@Tattytyres]

Hi iv got one for you, iv got a discovery 2 4.0 v8 and the maf sensor shows 5.5 g/s with key on and engine not running , strange? Iv checked x4 discoverys all with similar results, can you share a bit of knowledge on this thanks

[@mfreiher]

Hi. My engine is 2.5L, i get maf 70g/sec, at full throttle. Would that be a bad maf or throttle not fully opening? Thanks

[@syncrosimon]

Great information that few seem to know, many thanks🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@donpaulk7436]

My original is 3 sensor. One sensor shorted and burned out. I replaced with new and truck dies when plugged in. What are causes?

[@JPRZ1]

How can I get the spreadsheet

[@w210onpoint2]

Amazing video very informative and professional hard to find on KZbin lol

[@firestorm59739]

I just purchased a RAM 1500 Rebel. The mileage is supposed to be 19-24 and I have watched several videos where they test the truck and get that mileage. My truck is lucky to show 15 MPG and recently the miles left to empty showed 100. The truck has a 33 gallon tank and still had 10 gallons in it. Based on this, the math says that it most likely is getting the 19 plus MPG, but the sensor is telling me only 15 mpg. Your opinion?

[@antonispapaioannou2705]

Superb explanation and testing . Thank you. Please send the maf testing sheet.

[@MotorAgeMagazine]

Email me at [e-mail] and I'll send it over.

[@ВиталийЩербацкий-и8ю]

I ve read your article about low rpm problem with Scion Tc and very interested what the problem was? Or where can i read this. Thanks for help!

[@uvgot2bjoking]

What excellent knowledge, best on KZbin 👍. My maf on a 2.2 litre diesel saying at idle once at running temperature 7g/s and jumping to 12 g/s with an audible change in engine tone when switches from 7 to 12 by itself so definitely wrong reading straight away at idle. Going do test suggested first though too 👍

[@abdulbeany1894]

Hi i have a 2.0 diesel so should it read around 2 at idle thanks

[@shawndooglass9812]

Very nice n thorough

[@charlieahm6888]

I do have a question, how shoud I get the data from my mechanical transmission in the case stated in the video when shift from 1st gear to 2nd for auto transmission?. Thanks in advance. By the way, great video as always.

[@MotorAgeMagazine]

Good question! I would drive the car like I was running a drag race or passing a semi on a busy road. Rolling start, punch it, and shift into second when the RPMs got into the powerband.

[@robertfrancisco1193]

are you using both bank 1 and 2 STFT or one bank? thanks

[@MotorAgeMagazine]

Compare both to each other.

[@oluwatobikomolafe6626]

Very useful. Thanks for sharing. Will like it if you can share the excel document.

[@abdulwahedy5528]

My car skoda Octavia TDI 2018 shows 3 codes, P0103, P0341, P0113, what part should i replace?

[@rickyturner71]

😂😂😂

[@stuartsmith5633]

Using an Autel Mk808BT Pro, I am to do the driving test using the "generic or global obd2 mode" when testing my 2008 GMC 1500 5.3L LMG truck? Why, please explain?

[@russellnaj85]

Nice information, would i be able to get a copy of the mass air flow sensor calculations formula? it would be nice to have and to use it at the dealer. ive had fuel trim codes lately and im always second guessing when im looking at my mass air flow readings.

[@alexcoellor]

thanks for this video, and woul like to have access to de spreadsheet

[@wickedrobotwarrior6733]

Hi, I would like to get the VE spread sheet please.

[@AutoBioTech]

Thank you sir for sharing your knowledge

[@toshibahomeschool5704]

Leaking intake valves. Blow back into the intake manifold... Tight valve clearence? In hondas for example? Wich code will it be? 101/102/103???

[@7minnow]

GREAT Job🎃 keep them coming.

[@mundaJoel]

Can I please have the spreadsheet?

[@MotorAgeMagazine]

DOWNLOAD THE VE CALCULATOR AT docs.google.com/spreadsheets/d/1iaws3YdlXz3oz5v2kyupHtzveRhw_iaP/edit?usp=sharing&ouid=116905147516389752367&rtpof=true&sd=true

[@tanataur]

Hello , can i have the spread sheet ? Thanks Regards

[@sheerwillsurvival2064]

Can you tell me where this is on my 2013 Jeep Grand Cherokee. All I can find is a small air temperature censor . It’s a3.6 engine 🤷‍♂️

[@MotorAgeMagazine]

The MAF sensor is located between the airbox and the throttle body.

[@sheerwillsurvival2064]

@@MotorAgeMagazine yeah it’s not I’ve looked someone said it in the back side of throttle body going to look back there 🤷‍♂️

[@boomaf1620]

@@sheerwillsurvival2064 I just looked your car up in service data for you and your engine is a speed density engine design which uses a MAP sensor or manifold absolute pressure and not a MAF sensor. You can't find it because it's not there :-). Hope that helps. Cheers!

[@sheerwillsurvival2064]

@@boomaf1620 bless you though I was crazy 👊🏻👍🏻

[@sheerwillsurvival2064]

@@boomaf1620 thanks again for your help 👊🏻

[@rayman4102]

Thanks Pete! You said that the MAF should read about 1g/s per liter of displacement ( I am guessing per 1k RPM) is that correct? So on a 02 Corolla with a 1.8L motor at 700rpm I get 1.81g/s, does that seem about right? I have. P0171 with long term fuel trim at 25% (constant) and short term fluctuating between -10 to 12% when driving. Since trim doesn't get better with higher RPM I have moved on past a vacuum leak and suspect fuel side. Since it has also developed a harder time starting after sitting when hot (1/2hour sitting after running into a store). Any thoughts?

[@alrifainidal]

Any engine under 2 liter not apply to this . from 1 to 2 liter it should be between 2 g/s to 2.5 g/s when the car is stationary raise the RPM to 2000 - 3000 and look at the fuel term if it goes down this means you have vacuum leaks make sour you don't have a misfire drive the car and do wide open and watch the o2 sensor what it reports if it goes lean it means starving for fuel

[@rayman4102]

@@alrifainidal thanks for the reply. I don't detect a misfire since it's a 4 cylinder it would be hard to miss. I drove it while monitoring some data PIDs so if there was a vacuum leak LT trims should have come down but doesn't. Fuel filter has been changed as a precaution as it was on the original one with 145k. I really do need to check fuel pressure but the set I have doesn't have the right adapter so I may have to cobble something together. I can however drive down long term trims with a wot run. Plugged injectors is a possibility I guess.

[@drjimjam1112]

Plugged injector would yield decreased cylinder egt?

[@fernandoborda]

Can I get the ve calculator, Pete?

[@MotorAgeMagazine]

DOWNLOAD THE VE CALCULATOR AT docs.google.com/spreadsheets/d/1iaws3YdlXz3oz5v2kyupHtzveRhw_iaP/edit?usp=sharing&ouid=116905147516389752367&rtpof=true&sd=true

[@bbmd2200]

Hey, Pete. Since the MAF sensor is the primary source for calculating absolute and calculated load, can you just look at the calculated load value pid and make a decision based on it? Over 85 % is what I heard is okay for non- turbo or supercharged engines.

[@MotorAgeMagazine]

Calculated Load is ok for a rough estimation, and if it is turbocharged, Absolute Load is even better. But yes, you can use these numbers to identify an engine that definitely has a breathing problem.

[@Fireneedsair]

Can we get this info on an 200$ actron obd reader?

[@112rorz]

Hi, I have a 2013 BMW with 2 MAF sensors. When they are plugged in, I have random misfires, vibrations, misfires usually after gear shift. When I unplug the sensors the car runs super smooth and not a single misfire.. I replaced with 2 brand new sensors and it made no difference Any ideas?

[@Fireneedsair]

Also Can you link me to a VE calculator ?

[@The77stevo77]

GREAT VIDEO! THANK YOU! 👍

[@josiahvonb3426]

Would if you have a rough idle to stall issue and while the engine is running, you disconnect the MAF sensor and the vehicle will idle almost perfect, you can plug it back in and the engine will remain idling good and drive good but as soon as you turn the vehicle off or disconnect the battery then restart it the rough idle returns until you disconnect the MAF sensor again. The vehicle is a 5.3 silverado 08, this is all happening with a new MAF sensor since I just replaced it when the engine started acting up. I have been chasing this problem for quite some time and have replaced sparkplugs wires, coils, tps and I decided to check out the MAF sensor again when I discovered this anomaly. I don't know whether to get another MAF sensor or chase down wiring.

[@MotorAgeMagazine]

Do you have any codes stored in the ECM, hard or pending?

[@wildwildflorida]

Could be a problem with the communication with the computer in ur car. I hear this common problem. I’m dealing with it as well with Nissan Sentra with turbo. Trial and error, wish u all the best.

[@danieledwards6944]

can i have a spreadsheet please

[@MotorAgeMagazine]

DOWNLOAD THE VE CALCULATOR AT docs.google.com/spreadsheets/d/1iaws3YdlXz3oz5v2kyupHtzveRhw_iaP/edit?usp=sharing&ouid=116905147516389752367&rtpof=true&sd=true

[@ahmedelzade3326]

VE spread sheet please 🙏

[@skee0310]

Hey Pete could I get that VE excel sheet?

[@MotorAgeMagazine]

Email me at [e-mail] and I'll send it over.

[@Fireneedsair]

I have a 3.5 liter engine so are you saying my MAF should read around 3.5 g/s at operating temperature at idle? Mine is reading only around .6. Is it bad? Can something else be causing this reading besides the maf? I have a p0170 code. The car runs perfect no hesitation no variable idle. Stressing because I only have 3 weeks to get this to turn off CEL light and pass emissions .any help much appreciated

[@James-fs4rn]

👍 thank you

[@Screech-w2u]

I have a 2020 Nissan versa that’s popping a p0101 code, I looked up the bulletin for it and found that they actually had a bulletin for it that says just clear the code then do a IAVL that should clear it but wasn’t sure how likely that was to actually be the problem. Is the bulletins usually pretty spot on with its recommendations? The mechanic I’m seeing next Wednesday says they need to run the vin to see if it applies to my car.

[@wildwildflorida]

I have similar, delearship said 2800 to fix throttle body and MAF sensor pigtail require after paying over 1000$ to other mechanic. I change my throttle body, throttle relearn, changed my maf sensor, now I’m going to require the pigtail myself. Then use their scan tool reset my car. Nissan should do a recall

[@paulcoles9163]

pete if you do read this I was told by a tech that the mass airflow sensor was only there to check if and how much is added when the egr is opened as the ecu knows exactly how much air goes in based on engine rpm air temp and cylinder volume is this true , my 1400 deisel ran without mass af sensor , as had a broken lead in maf plug , only set a code

[@MotorAgeMagazine]

True on a diesel engine. The air entering is a constant as most diesels also don't use a throttle plate. RPM is controlled by the amount of fuel added.

[@paulcoles9163]

@@MotorAgeMagazine many thanks for your reply and your excellent training videos .i am currently improving my ecu knowledge with them

[@brunopecego5297]

i have a 1997 4.3 s10 with a severe rich condition negative trims -25. my MAF sensor reports 9gs at idle hot engine. i checked wires and didnt find a problem. i tried restricting the air by placing some rags in the air filter but it didnt change the sensor reading. i also dont get any blowback as seen by the MAP sensor which reads normal that could mess the MAF report. IAC valve closes and opens properly also. fouled spark plug sometimes after driving for longer periods. i take them out they are black so i know its not false rich. can you give me your opinion on what i should recheck?

[@SubePelayo928]

Mines doing the same thing. You figure yours out? I replaced the spider injector too. I was getting a rich reading on both banks and thought it was a leaking fuel regulator since the scanner showed -25 trims as well but had rich banks. Now that I switched the injector out. I’m still getting 9-10g/s

[@brunopecego5297]

@@SubePelayo928 still have the high MAF readings. they seemed to go down a bit after cleaning injectors but still higher than expected. i am suspecting my iddle air control valve system because i also have some irregular startup flare. i cant come up with any other explanation. i know it works but i cant check if how far in or out it its with engine running. let me know if you have any updates on your case in the future

[@brunopecego5297]

@@SubePelayo928 i also read in a couple forums that a restricted egr would cause a larger amount of air passing thru the MAF but I didn’t really understand how that would cause a constant high reading at idle where egr is supposedly closed. I did get a restricted egr flow code though but after a little bit of cleaning it got away and hasn’t comeback since

[@SubePelayo928]

@@brunopecego5297 I’ll update once i find a solution. It doesn’t make sense to me either. It could be faulty O2 Sensors sending a rich reading. Requesting more air and trying to reduce fuel trims too. But I’ll keep doing some research.

[@SubePelayo928]

@@brunopecego5297 I read that the IAC valve can cause the MAF to require more air. If the IAC valve is stuck or clogged. Giving a false reading of thin air/higher altitude. It can require more air to keep the air fuel ratio correct

[@stanley4089]

Hello sir I'm new to this I have ford f-150 5.0L 2013 it hesitates an shows code for mass air flow sensor P0113 circuit high input an IAT P0102 circuit low input an on scan tool mass air flow sensor reading is 2.36 -2.36 no changes Any help is highly appreciated

[@R.L.Thomas]

Third video about mass air flow sensors that call for replacement. In many cases the sensor is dirty and they make a special mass air flow sensor cleaner.

[@The77stevo77]

It doesn't always fix the problem. Sometimes the maf is bad. No amount of cleaning is going to fix it

[@JSchwaderer]

HI Pete, have a question. 2001 f150 5.4, with my scanner had lean codes and noticed no voltage reading on the maf sensor. I have 12 v going to it and a good ground, but do not have and voltage at the signal wire. Hoping its not the ecm. Any ideas?

[@MotorAgeMagazine]

Which wire are you checking for the ECM signal? Any DTCs set?

[@JSchwaderer]

tan with blue i believe is the color. Signal wire does not have a 5 volt reading

[@JSchwaderer]

dtc is PO102 low voltage. I just checked wires to ecm and check to have good continuity...

[@MotorAgeMagazine]

@@JSchwaderer My first thought would be a failed sensor.

[@JSchwaderer]

@@MotorAgeMagazine that's what I thought. So far they ohm ok.. I cannot get five volts from the ecm or ecm ground. Any ideas there? Doesn't the ecm have a body ground?

[@backroadscamaro541]

Maf shows average variance out of range at idle when driving shows normal what does this mean when out of range shows 2.26

[@MotorAgeMagazine]

What vehicle/engine are we talking about?

[@backroadscamaro541]

@Motor Age at idle 2.26 when driving normal iam not sure what this data point is for really 2014 buick encore 1.4

[@MrCoda47]

Would be great if I had and expensive reader like you do but he wants to spend that kind of money to use it once a year or once every five years

[@salahkanaan2579]

Please send me the be sheet

[@VileMisanthropy]

Mass air flow on 5.6 nissa. Reading 38 g/s at idle...

[@wildwildflorida]

They need to do a recall on the cars bc most mechanics not using no reprogramming software and tools

[@coyotedes6886]

My maf says zero with no check engine light…

[@nedhirdouiri]

1g/s for 1 littre is not always true specialy with BMW engine and I don't know why .. in normal operation the 1.6 engine have 2 g/s in idle.. maybe the valvetronic system is affecting something

[@MotorAgeMagazine]

The 1 g/sec per liter is a minimum, not an exact number.

[@jac6158]

Hello, do you have an email you can provide to send you the problem I’m having? Thanks in advance.

[@nickayivor8432]

PROFICIENT Sir Pete Meier Motor Age My teacher Sharing it thank you very much helpful information video Take care and have a great Evening PROFICIENT Sir Pete Meier Motor Age ASE =Automotive Service Excellence Richard McCuistian was ASE Master Automobile Technician For over 50 years Certified by Automobile Service Excellence for over 50years he deserves a interview 🙏 please thank you Sir Pete Meier Motor Age From Nick Ayivor from London England UK 🇬🇧

[@DzenanA-m6h]

I used Delphi sensors on my Lexus! Absolute garbage

[@hermeltalastas7487]

Absolutely garbage .

[@themaverickmechanic7240]

So far all the aftermarket stuff I’ve gotten from Delphi Technologies has been crap. Thanks for the video but step up the quality.

[@KStewart-th4sk]

In this video by "The Car Care Nut", he states that Toyotas WILL NOT set a code about a malfunctioning MAF. Is there something different about Toyotas in this regard? I just posted a comment to that video referencing this video, asking the same question. kzbin.info/www/bejne/nmm1e2eZedyhjJI

[@becca3823]

ρяσмσѕм 💘

[@MetodiHristov-q8o]

thats absolute useless video no help at all

[@billsmith2212]

If the Cat is partially blocked , will it affect the reading ? That would restrict the air flow . Or you can get the E Scan Elite from ATS ( Bernie Thompson ) which has a VE calculator built in !

[@MotorAgeMagazine]

Yes, any restriction to breathing will impact the test. And I have the EScan. 😊