How to test a MAF sensor using a Picoscope - GM
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- Опубликовано: 26 авг 2024
- In this video I will show you how to test a GM 3-wire MAF sensor using a lab scope. GM uses a frequency or digital type of sensor which will produce signals ranging from 2000 to 10000 Hertz (cycles per second). I will also show you how to identify and clean a dirty MAF sensor.
Engine Performance Diagnostics chapter 12 page 7
Symptoms
- stalling
- poor acceleration
- check engine light (MAF sensor codes)
- low power
- surging or bucking
Tests shown
- how to test a digital type MAF on a lab scope
- how to graph a digital signal
- how to measure a variable frequency signal on a scope
- how to identify and clean a dirty MAF sensor
Playlist
- (Chapter 12) Mass Airflow Sensor Testing
• (Chapter 12) Mass Airf...
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- How to test a GM MAF Sensor (Part 2)
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Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.
You Know Paul i bought your book and i am so excited with ever lesson you present i think you are amazing you deserve a hug
Bench testing one of these I used a drinking straw to blow on each resistor individually, it's the 2 resistors in parallel on the bars that go all the way through that sense and the one on the shorter bar is the reference.
Also with the inlet and outlet capped so that there is 0 flow it's interesting how much the orientation and thus convection currents affect the frequency, with the connector facing up (like the one on the car in the video) or down so the resistors are vertical I see just above 100Hz, any other orientation so that the resistors are horizontal it's closer to 200Hz
With the ends open even the slightest of air currents in the room make the frequency go up.
That's awesome
great question! I am not 100% sure on that. I know that the throttle is limited in park on some models so I guess the answer is yes and no and will depend on the system.I'll have to do a few tests and get back to you.
Paul I played with the pico demo before buying and the Pico seems way better than the snap I scope I have. Thanks to your videos I am going out to buy the picocope 4425. Bummer that you can get access to scanner danner on ASE Wave without buying the upper scope package. Just wanted to thank you for all you do as always.
I bought recently a pico and this video is really helping in providing info how to use
So use the "approved" cleaner then. Close inspection of the hot-wire will show that spraying cleaner alone is not good enough at times. (no matter what you use) I have seen crap on the hot-wire that must be brushed or scraped off so there is a need to be more aggressive otherwise MAF replacement is necessary.
There are some that claim any type of cleaning is bad. To each his own. I've been using brake cleaner for over 15 years on hot-wire type MAFs with NO ISSUES!
One of the best channel in the world for learning.
PAUL, WHEN I CLEAN THAT TYPE OF MASS AIRFLOW SENSOR, I TAKE THE 4 BOLTS OFF AND HAVE PLENTY OF ACCESS ON THE AIR FILTER SIDE, I DO LIKE THE WAY YOU BEND THE BRUSH GREAT IDEA BRO!!!!!
on this hot wire type I've been using whatever kind of brake cleaner that is laying around. and I have been doing it for the past 15 years with no problems. that being said, however the "experts" say you must use a special Mass Air Flow cleaner, and I cannot argue with being cautious
I just cleaned mine, I found it was way easier to take the four Allen bolts out and clean it with a Q-tip.
Very good video. Always like learning the ins and outs other than just learning how to replace a part.
Keep up the good work.
I love these video's. I'm relatively new to the field, and the info is fantastic. Cheers Paul
A trick: watch series on flixzone. I've been using them for watching all kinds of movies recently.
@Zane Lucca yea, I've been watching on flixzone} for months myself =)
Ok good point on any type of cleaning. I will agree, possible risk damaging the MAF anytime you clean it, no matter what. Just a side note, I read the MSDS as I do on most solvents cause you never know what's in there. That brake cleaner contains Trichloroethylene or TCE, most brake cleaners do. So I would advise as the MSDS does to wear gloves. Preferable a nitrile type.
@contagiousFX On the red trace on this video you saw a really thick red line using a longer time base. This is how you will know it is digital. If it was an analog type it would look like the graphed frequency trace (blue trace)
Another great video! Curious though, why did you choose brake clean? I have always been told to use MAF cleaner only and that anything else will damage the sensor. But hey, if SD says it’s okay it’s more than likely okay! Thanks for all the excellent content Paul, you’ve made a very positive impact on this industry!
Paul, great video!!! I am not sure if you or anyone mentioned if the air filter was a ac delco/gm air filter or after market, I have seen some after market air filters cause MAF issues, and also the condition of the air filter, clean dirty etc.
@RUSS16V2 I'll check for you tomorrow when I get to work. You could also post this question in the pico forum. It is picotech dot com
Excellent video! It's like been sat in a real workshop classroom! Your
@TRcustomengineering I'll look into it for you
wow its so awesome how you explain in great detail. Live data is the key and the initial spike is what we are looking for. thanks for such a great video. now i see the importace of just sampling diferent cars to see whats happening and refreshing our memories.
한국어로 번역하면 좋겠습니다ㅠ
@RUSS16V2 The frequency graph I was using is only on the 4000 series pico. What model do you have? My older 3000 series couldn't do that test.
Great demo Paul,love your videos
@Bushougoma Thanks for the part number, I knew they made it but I've never used it. Not saying that I shouldn't be, but I have never hurt this type of MAF with brake clean...ever. Maybe some of the newer style MAFs would be more sensitive and we should use the special cleaner. I noticed snap-ons troubleshooter was updated to recommend the use of MAF cleaner. For over 10 years it used to say brake cleaner. So maybe there is some truth to it or everyone is just trying to cover there ass.
@ScannerDanner it's a 4000 series. I can see the frequency scale in the preset notes but when I press the space bar and go live the scale is then a 100V.?
thanks Sam
Paul, I've just tried to have a go at work with my pico but when I select the preset,channel A is set to 100v and there is no frequency option? I've looked in the AC/DC coupling but nothing there. Am I missing something?
@kruno45 Of course
can graph be used on a road test to check for linearity instead of g\s during acceleration
What would it look like of the sensor was defective?
Love your vids Paul,Ian going to upgrade to a pico soon
nice video Paul, that this principal apply to Toyota VAF sensor I understand that works as potentiometer the point is this at idle is about 5 volts , when I do quick snap it should drop close to 0?? thanks
At 4:10 there was a spike line going of the scale. Does that indicate MAF faulty? (It didn't happen after cleaning). I think I seen that in one of your other vids showing difference between scope and multimeter.
Edit: It was at 5:57 on "How to test GM MAF sensor part 1". You failed the sensor there but not here. Why?
Excellent vid.
What not separate the mass air flow sensor from the aluminum housing to clean it easier.
Fantastic,Thanks !!
Nice video,is there special cleaner for MAF sensor ? And which one you recommend ,thx
Another excellent video
Man do I really want a pico.
What do you think of the pico 2202 vs the snapon vantage I asked you about the other day?
I think I can get my hands on a pico 2202 for a pretty good price.
Thanks
@chamosvin That works too thanks:)
Great video. One question: is there a possibility that the MAF sensor could produce a signal on a not running engine? Buick LaCrosse with a 3.6L engine, the digital MAF displays about 2 kHz square wave signal even if the engine is not running.
Yes, some will produce a signal with just the key on. Not sure of 2k hz but I've definitely seen a few hundred hz
@@ScannerDanner Thanks, Paul. So, it could be normal to see some signal with the key on? On a scaner, I have seen 4 g/s. Seems high to me for the not running engine.
@@74santon yes, this could be completely normal. It is not uncommon to see ABS wheel speed sensors all read 3 mph with all the wheels sitting still. My point is that sometimes scan data can be misleading
lol thank you my friend
@ScannerDanner Thank you, much appreciated.
Helpful video!
thank you
i see you are using non clorinated brake cleaner on it , I was told never use that but i guess is ok! thanks!
Thank you.
Great videos and explanation.
How do you have the giant pico with touchscreen on the projector setup ?
+bbogdanmircea it's called a smart board and I teach at a technical college
does the hantek 1008c have the capability of graphing the frequency?
no idea, sorry
So why would it get worse after cleaning? Just curious
It was worse in this video? Not from memory it wasn't.
@@ScannerDanner yeah if you look at the beginning graph before you cleaned it and after it actually got a little worse. Unless I'm missing something
@@tensecondbuickgn no improvement on the cleaning on this one. I even said that in the video. It certainly wasn't worse. Thanks!
Some of these are wired this way and it's normal
Hey there I just Purchased ur book and I no u changed it to use 5kohm resistors for some test cant find 15kohm resistors only 10kohm is that ok to use for those test ???
you can use your test light as a buffer instead
Thank u I'm a part changer looking to be able to Diagnose a problem I wach ur RUclips and I got ur ebook thanks for putting up these videos to show how to
@@Ryan-pm9le you won't be for long :-) (a parts changer) thank you!
@TRcustomengineering With the new features and scope protection in the Pico 4000 I would say save your money a bit longer and get a Pico 4423 from Autonerdz they have great training material, support, and member forums. That's where I bought my 4423 best $2300 I've spent. And like I said go for 4 channels because if you go with 2 you will just be spending your days wishing you had 2 more channels.
what do you mean "re-post" this is the original video
Hi Paul,is the test for a hot film afm the same as for a hot wire afm.....Many thanks
👍
So using brake cleaner and touching the sensitive sensors with a screwdriver is optimal? CRC makes an approved MAF cleaner. $8.
hi. what can be used to change the frequency of this type of maf sensor to lean the a/f mixture?
+Guy de vries nothing I am aware of, sorry
Don't MAF sensors clean themselves? My late 80s car's ECU makes the MAF do a burn off after a certain volume of air has passed through it.
very very great work but please i have jeep liberty 2007 how i can test the maf sensor its digital one too ? how i can test it ? i clean it but its a same problem i have start delay issue please if you help me ?
+amjad amj there is no MAF on a 2007 Jeep liberty. I'm pretty sure this is a speed density engine (MAP sensor with no MAF)
thanks friend well try to find the map sensor
@frosty9595 Go to my website listed on my channel page. I cannot post a web link in here. Or send me a private message and I can get you more info. on it that way