One thing to note in the video: I gave a brief explanation of how the fuel injectors flow rate is regulated by the ECU. To simplify things I used a simple square wave and used positive side triggering which is used in older European vehicles. The most common is NEGATIVE side triggering. The waveform will look very similar to what was shown if you invert the image. Keep in mind, when the injector turns off, you'll also observe a brief spike due to the collapsing magnetic field of the injector.
Modern high impedance (multiport) Fuel injectors are not duty cycled (% on time) they are frequency modulated. They are either fully on or fully off, but the time they are on changes (time on either increased or decreased and in measured in milliseconds based on engine requirements). Older Throttle Body style injectors with low impedance (and subsequent high current flow) used PWM % on time) because full current was only required to initially open the injector, then a lower current can be used to hold the injector open. The lower “hold open” current was Pulse Width Modulated (PWM) to prevent the coils from overheating.
Nice video. Very informative. Yep been there and done that fighting an aftermarket mass air flow sensor for a Nissan truck. I would advise anybody to avoid the Chinese knock-offs just because not only are they not accurate but they don't insulate around the circuit boards and even temperature change on the circuit itself will throw it out of calibration. I've also seen issues with RFI where they did not protect the board from electrical noise which would cause the unit to malfunction also. Once again a very informative video. Thank you
splendid presentation. uncharacteristically so. Moderator sounds and presents material like a professor who could double teaching fairly high level English. how could I have missed this channel. gratefully
donald murray Thanks for the kind words Don! Be sure to check out my extensive video playlists, rate thumbs up, and share my channel with others. Thank you
Glad you enjoyed the video. Be sure to look over my extensive video playlists below for many other videos of interest to you, and share links to my videos with many others on social networking sites. Thank you, and stay safe! ruclips.net/user/electronicsnmoreplaylists
Glad you think so Jaime! Be sure to rate thumbs up, subscribe, and look over my extensive video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Thank you ruclips.net/user/electronicsnmoreplaylists
Glad you enjoyed it Tim! Be sure to look over my extensive video playlists below for many other videos of interest to you, use supplied Amazon links to support my channel when making purchases(No added cost to you), and share links to my videos with many others on social networking sites. Thank you! ruclips.net/user/electronicsnmoreplaylists
@@electronicsNmore Thank you. Bmw e46 320i m52 b20 tu engine airflow meter resistance repair but which material I will use is very expensive, so I need to fix it I'd appreciate it if you'd give me some information for him.
I recognize that MAF sensor anywhere you must drive a E46 or E39 bimmer, I'm currently have issues with my MAF, i so far bought 3 brand new from NAPA - refurbish, auto zones Duralast brand, then finally bit the bullet and bought the OEM from BMW dealership and all of these MAF's when plugged in where making my car stall on cold start, idle rough, accelerating issues etc., when unplugged my car drives fine. and i don't have any vacuum leaks i checked all those. I must be the luckiest person in the entire world to have bought 3 MAF sensors that are bad and faulty. I remember buying one from pelican parts few yrs back and my car ran perfect instantly!! So I might have that one again soon. these cars are really picky when it comes to buying sensors.. what are your thoughts on this??
Hi Doug. very well explained has always. I use an 8 channel scope that connects to my laptop the price was reasonable and it works great. It will save the wave-forms so they can be compared to the correct wave forms that you can find online. All my best. Bobby
You're welcome! Be sure to look over my Auto/Mechanical video playlist below for many other videos of interest to you. Thanks ruclips.net/video/hnd7P7O_vEQ/видео.html
A failure mode that has occurred two times for me where the MAF "died" both involved an attempted restart after a short stop. The engine would act as it was not getting fuel (it wasn't) but not because of the fuel pump. I suspect the burn off mode is what killed the MAF
nice video very rare to find someone go to this detail, would have loved to see the part numbers on that chip, maybe a voltage to frequency convertor using an quad op-amp, my guess is, its frequency is proportional to airflow which the determined by those blue x2 NTC resistors.
Most people don't know this but one way a mass airflow sensor fails is due to high voltage spikes on the 12V supply line and mainly due to a bad alternator regulator, the chip on that MAF device has no TVS or zener voltage clamps on the MAF PCB to clamp spikes on the vehicle's battery line, so any spikes destroys it or partially runes the calibration due resistor carbon being destroyed.
After getting an 'engine check' light on the dash of my 2015 eco-diesel (traced to a mass air flow sensor issue) I was able to clear the light simply by changing the air filter. I found a mouse nest build-up on the intake side of the filter and after vacumming the filter unit completely and changing the filter, the light cleared itself after about 5 miles of driving. Try this 1st - it costs little to nothing and should be done anyway.
Not to diminish your video by any means, I had watched this before I had removed the filter box and found the mouse nest. I had also purchased a can of MAF cleaner from the parts store fully expecting to have to clean the sensor - which I will still do if the engine check light comes back on and the filter is still clear. Good video.
Glad you enjoyed the video! Be sure to watch my other Automotive & Mechanical videos below, and most importantly share my channel with many others. Thank you! ruclips.net/p/PLQ6IOhUBblU3mBem9ImEgGzmqToW6SCJD
They both do the same thing for the fuel system, but how they do it is different. One uses a hot wire/sensor, and the other uses a different method. Look up an online service manual for your vehicle. Thanks for watching Don!
With the engine off I pulled the plug on the maf and engine runs fine took car for a spin and no issues car is a 911 996 02 model So what is at fault here no obd faults showing
One thing to note in the video:
I gave a brief explanation of how the fuel injectors flow rate is regulated by the ECU. To simplify things I used a simple square wave and used positive side triggering which is used in older European vehicles. The most common is NEGATIVE side triggering. The waveform will look very similar to what was shown if you invert the image. Keep in mind, when the injector turns off, you'll also observe a brief spike due to the collapsing magnetic field of the injector.
Modern high impedance (multiport) Fuel injectors are not duty cycled (% on time) they are frequency modulated. They are either fully on or fully off, but the time they are on changes (time on either increased or decreased and in measured in milliseconds based on engine requirements). Older Throttle Body style injectors with low impedance (and subsequent high current flow) used PWM % on time) because full current was only required to initially open the injector, then a lower current can be used to hold the injector open. The lower “hold open” current was Pulse Width Modulated (PWM) to prevent the coils from overheating.
Nice video. Very informative. Yep been there and done that fighting an aftermarket mass air flow sensor for a Nissan truck. I would advise anybody to avoid the Chinese knock-offs just because not only are they not accurate but they don't insulate around the circuit boards and even temperature change on the circuit itself will throw it out of calibration. I've also seen issues with RFI where they did not protect the board from electrical noise which would cause the unit to malfunction also. Once again a very informative video. Thank you
Glad you enjoyed and appreciated my video. Be sure to rate thumbs up, share with others, and watch my video playlists. Thank You!
splendid presentation. uncharacteristically so. Moderator sounds and presents material like a professor who could double teaching fairly high level English. how could I have missed this channel. gratefully
donald murray Thanks for the kind words Don! Be sure to check out my extensive video playlists, rate thumbs up, and share my channel with others. Thank you
Nicely explained with clear detailing. Thanks a million.
Glad you enjoyed the video. Be sure to look over my extensive video playlists below for many other videos of interest to you, and share links to my videos with many others on social networking sites. Thank you, and stay safe!
ruclips.net/user/electronicsnmoreplaylists
this was a perfect explanation, thanks 😊
Glad you think so Jaime! Be sure to rate thumbs up, subscribe, and look over my extensive video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Thank you
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nice explanation
This was very well done. Thank you.
Glad you enjoyed it Tim! Be sure to look over my extensive video playlists below for many other videos of interest to you, use supplied Amazon links to support my channel when making purchases(No added cost to you), and share links to my videos with many others on social networking sites. Thank you!
ruclips.net/user/electronicsnmoreplaylists
@@electronicsNmore
Thank you.
Bmw e46 320i m52 b20 tu engine airflow meter resistance repair but which material I will use is very expensive, so I need to fix it
I'd appreciate it if you'd give me some information for him.
I recognize that MAF sensor anywhere you must drive a E46 or E39 bimmer, I'm currently have issues with my MAF, i so far bought 3 brand new from NAPA - refurbish, auto zones Duralast brand, then finally bit the bullet and bought the OEM from BMW dealership and all of these MAF's when plugged in where making my car stall on cold start, idle rough, accelerating issues etc., when unplugged my car drives fine. and i don't have any vacuum leaks i checked all those. I must be the luckiest person in the entire world to have bought 3 MAF sensors that are bad and faulty. I remember buying one from pelican parts few yrs back and my car ran perfect instantly!! So I might have that one again soon. these cars are really picky when it comes to buying sensors.. what are your thoughts on this??
I really enjoy these very informative thumbs up videos you do. Thank you for sharing
Glad you enjoy them. :-)
Really informative and helpful, thanks!
Great to hear!
Hi Doug. very well explained has always. I use an 8 channel scope that connects to my laptop the price was reasonable and it works great. It will save the wave-forms so they can be compared to the correct wave forms that you can find online.
All my best.
Bobby
Great for watching all injectors at the same time.
Thank you. Useful video.
You're welcome! Be sure to look over my Auto/Mechanical video playlist below for many other videos of interest to you. Thanks
ruclips.net/video/hnd7P7O_vEQ/видео.html
A failure mode that has occurred two times for me where the MAF "died" both involved an attempted restart after a short stop. The engine would act as it was not getting fuel (it wasn't) but not because of the fuel pump.
I suspect the burn off mode is what killed the MAF
Possibly, I had one fail just like that in the past.
Very good, I wonder what the failure rate in manufacturing is why do these things cost so much?
OEM units usually use platinum heating wires instead of thermistors, and of course you always pay more at the dealer. :-)
Keep up the good work, greatings from Denmark
Thank you! Be sure to check out my extensive video playlists, rate thumbs up, and share my channel with your friends.
very good explanation about MAF sensor thanks
Glad you like it! Be sure to rate thumbs up and share. Thanks
But does removing the mesh in the sensor, in a diesel engine, make a difference in the efficiency?
nice video very rare to find someone go to this detail, would have loved to see the part numbers on that chip, maybe a voltage to frequency convertor using an quad op-amp, my guess is, its frequency is proportional to airflow which the determined by those blue x2 NTC resistors.
Most people don't know this but one way a mass airflow sensor fails is due to high voltage spikes on the 12V supply line and mainly due to a bad alternator regulator, the chip on that MAF device has no TVS or zener voltage clamps on the MAF PCB to clamp spikes on the vehicle's battery line, so any spikes destroys it or partially runes the calibration due resistor carbon being destroyed.
Can you hep me which resistance should I take
After getting an 'engine check' light on the dash of my 2015 eco-diesel (traced to a mass air flow sensor issue) I was able to clear the light simply by changing the air filter. I found a mouse nest build-up on the intake side of the filter and after vacumming the filter unit completely and changing the filter, the light cleared itself after about 5 miles of driving. Try this 1st - it costs little to nothing and should be done anyway.
Lucky for you that's all it was. :-) Thanks for watching! Be sure to look over my extensive video playlists and share my channel.
Not to diminish your video by any means, I had watched this before I had removed the filter box and found the mouse nest. I had also purchased a can of MAF cleaner from the parts store fully expecting to have to clean the sensor - which I will still do if the engine check light comes back on and the filter is still clear. Good video.
Can these sensors be used to take readings into Arduino and then calculate the amount of Volume output from a system?
I never tried.
@@electronicsNmore Oh okay :/
Was this maf running rich ?
I forgot the exact symptom, but it triggered O2 sensor codes, and caused my transmission to not shift properly. Thanks for watching!
Cool Video!
Thanks Bob
very good from iraq
Glad you enjoyed the video! Be sure to watch my other Automotive & Mechanical videos below, and most importantly share my channel with many others. Thank you!
ruclips.net/p/PLQ6IOhUBblU3mBem9ImEgGzmqToW6SCJD
Would you be interested in working on an MAF based flow meter for us.
Thanks for the offer, but I'm already too busy.
What if my car does not have a mass air flow sensor but it does have a mass air flow meter
They both do the same thing for the fuel system, but how they do it is different. One uses a hot wire/sensor, and the other uses a different method. Look up an online service manual for your vehicle. Thanks for watching Don!
great
Glad you enjoyed it! Be sure to watch and share my "Auto/Mechanical" video playlist below. Thank you
ruclips.net/video/hnd7P7O_vEQ/видео.html
mine experiences hesitation while accelerating, mostly up an incline..
What is Blue component name sir
thermistor
The blue packaged device are thermisters
They looked like axial PTC's initially, but then I thought I saw very fine wire wrapped under the blue coating.
My honeycomb is all crushed and bent and my engine hesitates and cuts out power on boost
Sounds like a faulty TPS. Also sounds like you need to replace the MAF.
I hate resin coated circuit boards - it ruins the fun of reverse engineering things
Yes, definitely a problem.
With the engine off I pulled the plug on the maf and engine runs fine took car for a spin and no issues car is a 911 996 02 model
So what is at fault here no obd faults showing
Try resetting the computer. Could be a faulty MAF, another sensor, or ECM problem.
I don't think the air outlet is a honeycomb. They look like little squares to me.
Yves Baggi
Does it make any difference to the video?
No, the air inlet is always the honeycomb. I'm sure you saw the arrow in the video.
I thought MAF stoud for Massive A$$ Flow J-king 😆