Working on my friend's 2000 Tacoma truck today. Same P0171 code, plus a P1133 (A/F sensor circuit response). Drove around, long term FT topping out at +39% at higher engine loads, but negative at idle. This video instantly came to mind. Checked fuel pressure just to make sure, then went after the MAF. BINGO! A little electronics cleaner and a light brush...truck drives like new now! So why don't these sensors have a self-cleaning burn-off circuit like older MAFs? Once again,you're the man, Paul!
friend had a '01 Lexus GS300, P0171 and P0174. Did exactly what you showed on your video with my ETHOS Snap On and figured it out. Thank You!! Though I worked at a dealership for 7 years as a used car tech and graduated UTI, nothing compares to your skill. I hope I can get to your level. Next buy is your book. Thanks again.
Yes. The MAF sensor is actually a mini computer. All of the conversions are done inside of it. All computers need a main power and ground to work. So you can think of the 12v feed and ground on this MAF sensor as the same thing. IT is actually a MAF module.
Thank You Very Much. I just purchased a 2000 Corolla and after changing the spark plugs didn't fix the problem I guessed it was the oxygen sensor. So $85 dollars later I was feeling a little worried when I still had the same problem and not sure where to go. Your video saved me a lot of time, worry, and most likely money. Just removing that little bit of dirt made all the difference. Thanks for the video!
After clean the maf sensor the idle is fix and running good for a test drive but for second test the p0300 came back but is not misfire a lot LTFT --10 on both bank.. thank you for the time I know your are working hard every day. god bless you..
thanks man! keep at it bro you are at that threshold now where great things happen. experience is so critical isn't it? i have so much to learn still too. it never stops
just bought a 2001 Corolla with code PO171 thinking O2 sensor, reading some tech found more likely a dirty MAF - this video is awesome! I not only see the how and why it makes sense - but your explaination helped me understand data I have been logging on a racing V8 car as well with fuel problems. this is internet at it's best, thanks for sharing!
Thanks alot! My hilux has been missing and hesitating for weeks, I had done some AFM testing and given it the all clear. Your video made me go back over it and sure enough, it was filthy. Quick clean and it's back to normal. I was just a couple of days to taking it to a workshop and probably copping a $500 bill! Love your work!
This info is absolute gold! Best diagnostic videos on the web hands down. I highely recommend the ebook people, I will be buying the lecture videos also. Thanks for the wealth of info paul, keep up the good work!
this video is not for amatur mechanics. It is accurate and packed with infomation for trained professionals who may have missed or are trying to deepen there knowledge. You have to watch it a few times to gather all the info and check out other videos and spend some time studying. Great and accurate video as usual. thanks paul.
Good question, as for the vacuum leak issue. I have never seen that effect the baro calculation. Also after cleaning the MAF, you have to reset the KAM or disconnect the battery for awhile to clear the baro calculation in memory.
great videos scannerdanner lots of good info,i just graduated from ATS school in sacramento and i am getting ready to test soi am reading all my books and watching all your videos very helpful thankyou.
I've been watching your videos for years and have been a technician for 30 years.. When i started to be really interested in MAF sensors i was seeing a hell of a lot of hot film style here in Europe.
@GamingJediPwns you are mistaken on that comment. this style of hot wire maf is not damaged by the cleaner i used. its just a heated resistor with a glass covering. I've been cleaning them this way for 15 years with ZERO comebacks
The IAT is a thermistor and the "cold wire" is possibly a thermistor, but the "hot-wire" is a resistor. (technically a thermistor is a resistor) Thermistors are generally used in voltage sensing circuits. MAF circuits measure the current flow needed to maintain hot-wire (heated resistor) temperature above ambient, then convert this to an electrical signal (analog or digital) that is proportional to the current flow and therefor in-coming airflow
Cheers man. Just recently bought a Celica GT-S and suspect I'm having almost the exact same issue. Replaced Spark Plugs and put injector cleaner in, didn't help much with my lag. Figured it was a MAF Sensor issue. Going to clean it this afternoon and get back to you :) This vid helped a lot, cheers!
@import0408 I hesitate to say all but most yes. The older vane airflow meters on some of the cars had high voltage at idle and it would drop under load, so opposite of the others in operating range.
I'm ok with the initial drop lean on a rapid snap to WOT(sometimes you see that, sometimes you don't). Just make sure it stays rich the entire time after that.
thank you , it was perfect answer, it clarified every question was in my mind. you know Paul I talked to my snap on dealer I made a letter for snap on he said he was going to handle to some one in chart there for diagnostic I told the guy you are teaching us how to use the verus and how to test the sensor with the tool on real vehicles problems I told the dealer guy you should get some credit for that I hope they do some thing you really deserve it.
This is so awesome man. My 98 camry was running lean base on my fairly new plugs having ash like build up and power reduction at increased RPM. found you video and it surely help me to understand a bit more of whats going on. dont have all your test equipment but now know the expected output voltage from the sensor when I do my volt meter test. As an electrician I know the benefits of the right test equipment. great job on the video.
don't worry about the STFT with the engine cold and in open loop. The numbers are irrelevant. So do you have positive or negative fuel trim numbers when warm. mainly the LTFT is what I need
i believe that is an analog type maf sensor and the signal should read more than 4 volts at wot redline. with a dmm you will need to drive it to see that number as the meter isn't fast enough for a wot snap test in park. You could also look at the stft and see if it tracks positive with a rise in the maf signal, this would also indicate a maf problem.
@03mazpro a dirty mass air flow sensor will not cause a catalytic converter trouble code. if all you have is a converter code and no exhaust leaks then you need to replace it. as for cleaning the mass air flow sensor as long as it is the style in this video then it is cleanable and brake or carb cleaner is fine
Low MAF grams per sec at WOT, also low voltage during a snap while we were testing it directly under the hood. These were the clues that the MAF was the problem and not fuel pressure.
@contagiousFX What numbers? Fuel trim should be +/- 10% MAF grams/sec and frequency will depend on year and engine size to name a few. For most of the GMs I look for at least 150 gram/ sec at WOT and a frequency of over 8500HZ, Idle would be around 2.3-2.4khz. But again there are variable.
The car most likely also had some fuel trim trouble codes too. If the MAF is reporting the wrong airflow the a/f ratio will be completely wrong and this can cause misfiring. Usually this is accompanied by lean or rich trouble codes as well.
Does the sensor under report or over report when it’s dirty? I get that the O2 shows lean and it’s dumping fuel, but it’s only reading lean because of what the maf is reading. So does that mean the maf is over reporting airflow? If that’s the case why are airflow numbers greater with the clean sensor? I’m just confused as to how the MAF causes the O2 to misread if the calculated air was less with the dirty sensor? Am I misunderstanding and the maf is under reporting and it’s fueling for what the MAF thinks is passing but the actual air charge still passes and leans out the mixture the MAF thinks it is dealing with? Then that causes the pcm to infinitely rich the mixture because it will never record absolute air flow
@@DDR233 a dirty MAF will under report airflow under loads. Some will over report at idle only, but both types will under report under loads. This causes the base fuel map to be skewed as the engine load is being under reported too. So positive fuel trim numbers result. Positive trim numbers does NOT mean rich!! It is a rich command caused by a lean condition.
Yes A MAF DTC with good MAF sensor usually sets a “range/performance” code and may be caused by the following: TPS problem Vacuum or air intake leak Oil cap or dipstick problems PCV system leaks Dirty/plugged air cleaner clogged exhaust
I've seen them set for only one bank but if you look at the trim numbers both banks are affected. It just flags one side because it is worse than the other. (sometimes)
Did you do the resistance check I showed in part 2 of the one video? This is your only option without a scope, unless you get lucky and the shorted injector is one of the two injectors you can get to without removing the intake. There are other causes of this condition on your car, but lets do a resistance check on the injectors first.
yes i did the resistance check and found one injector at 5 oms and 3 others at around 9 ohms so i did have shorted injector ,was my starting issue.hey thanks alot for your help i was going crazy with this hard to find issue for 3 weeks .thanks again for sharing knowledge i saved alot of money doing it myself. gm 2.8 fixed good day
Thanks to Paul danner I can't look at vehicals the same anymore. The book he put out is worth every $ your pay. My life has realy changed thank you paul. I can't wait to see more videos and I'm really hoping you put out an other book I know there is more you have discovered to teach us. I soon will have my L1 certificate. Thanks to you again. Keep up all your doing its great.
All new stuff right now is in the form of video lessons on my Premium channel. I may write another book someday, but for now, come join my classes! Thanks
Just subscribed to Your account,Your uploads are excellant,have learned so much in a short space of time.I will definitely buy your E Book,I've never had anyone to learn much from about diagnostics so i'm very impressed with Your information and delivery which is easy to understand.keep up the Good work from Paul in Ireland
@lesbirel91 A dirty MAF is not the only cause of a lean exhaust trouble code. If you have my book check out Section 5 page 5. The list on this page address the most common causes for P0171 and P0174 DTCs
There are two grounds because the PCM MAF signal circuit actually gets its ground through the MAF sensor. So one ground is PCM to MAF and the second ground is MAF to the block. If the MAF to the block ground is bad, BOTH grounds will be bad. No 5 v ref. on this design.
if the o2 is switching before the wot run then it is not an 02 problem. it is a fuel delivery problem. low fuel Psi and dirty MAF are the top two. a severe misfire can also cause this
If you're reading the values from a diablosport predator, I believe the output for the "baro hz" isn't the actual hz, its that number converted to "Hg based on a table. So a reading of 30Hz is actually 30"Hg...or approximately sea level.
haha I actually used a fine-tipped dental pick, but don't tell anyone! A little compressed air helped too. Those wires were pretty gunked up...not to mention his airbox was full of dry leaves lol
Great Video, I can barely see 1 Thermistor (Temperature Thermal Resistor) when it was dirty at 07:30, and you can clearly see both afterword's at 08:56, Everything looks Clean, Dry, and Tight.
The check engine light will set the other two lights. They are the traction and vehicle stability control systems. Fix the check engine light and you will automatically get rid of those other lights
Thank you for your response , so it receive 12 volts external the maf and some way inside the maf it is converted to 5 volts Out put sensir signalto PCM is that rigth?? Because on snap throttle I saw about 4 volts. Thank you , you are a great teacher
Paul, MAF air flow depends on HP. The 2000 Toyota has 125 HP so max air flow will be about 110 gm/sec. An E39 M5 has 400 HP so max air flow is 350 gm/sec.
not a dumb question. you cannot use the downstream sensor the same way because the cat catches and stores oxygen. there is some diagnostic advantage though but it is not used the same way. check out my o2 fixed lean case study
If it was a 2 bank system then yes, a dirty MAF would affect both banks. But this is only a 1 bank 4 cylinder engine. Bank 2 doesn't exist. Great question though, it means your thinking!
Great test i like the veruss min max capability however i always use my dvom when reading o2 signals ive just been burnt to much with false readings but overall that was a great test got straight to the root without even having to check fuel pressure
There are other causes of those lean exhaust codes. Sounds like you need to take it to a competent mechanic. It doesn't matter if he is an aftermarket guy or a dealer guy. Go to iATN and search for garages in your area. If they are iATN members you have a better shot at a good tech.
Yea, I know I should take it off as I am not showing proper safety procedures with it on. I am super careful of where I put my hand and truthfully I would rather take the chance than take my ring off. It is sacred to me. (I do take it off if I am reaching my hand near a starter motor or alternator that I cannot see very well)
that build up is call insulation and insulation traps heat. air coming in is designed to cool sensor but good insulation wont allow that. great case study.
Dan , if you know you have a good MAF for sure. Is it possible for the computer for give a MAF fault code on a scan tool , even with a good MAF sensor . 1999 olds intrique 3.8. thank you
Danner,great channel buddy. As a hobby mechanic, and a guy who mostly tinkers with *gasp* carbs, I can only dream of having the diagnostic tools and knowledge that you've acquired over the years. But I appreciate you showing us how it really should be done by good, experienced mechanics. Quick question for ya. On my 96 Mustang I had a P0172, if I remember correctly. I chased it for months with new vac hoses, sensors, etc. Ended up being badly arcing plug wires. Does that sound right to you?
Higher than normal Co means the car is running rich. If you have my eBook, Section 5 page 4 gives a list of causes of richer than normal conditions. Here is the list:Higher than normal fuel psi Ruptured fuel psi reg. diaphragm Leaking fuel injector EVAP purge problems ECT or IAT sensor problems MAP/BARO or MAF sensor problems EGR valve stuck open at idle Fuel contaminated oil Head gasket leaking causing coolant contamination of the O2 Jumped timing chain/belt
The VVT-I configuration did not exist on the 98 Corolla, it started on the 00 model year. Check your fuel pump pressure. Had the same problem on my 98 Corolla at around 200,000 miles. New fuel pump cured the problem.
hi there mr. danner great videos BTW. i just have a quick question for you. i have a 2000 volkswagen passat with multiple misfire, the mechanic change the MAF sensor and run like a charm again.now how could a MAF sensor trigger a multiple misfire? thanks scanner danner keep up the work
I don't think there was a problem at all with the scan data. I think this was simply a small engine that doesn't "breath" the same amount as other engines do. Remember every car is different as far as what peak grams per sec will read.
Working on my friend's 2000 Tacoma truck today. Same P0171 code, plus a P1133 (A/F sensor circuit response). Drove around, long term FT topping out at +39% at higher engine loads, but negative at idle. This video instantly came to mind. Checked fuel pressure just to make sure, then went after the MAF. BINGO! A little electronics cleaner and a light brush...truck drives like new now! So why don't these sensors have a self-cleaning burn-off circuit like older MAFs? Once again,you're the man, Paul!
friend had a '01 Lexus GS300, P0171 and P0174. Did exactly what you showed on your video with my ETHOS Snap On and figured it out. Thank You!! Though I worked at a dealership for 7 years as a used car tech and graduated UTI, nothing compares to your skill. I hope I can get to your level. Next buy is your book. Thanks again.
A trick: you can watch series at flixzone. Been using them for watching a lot of movies recently.
@Lyle Andres Yea, I have been using flixzone} for since december myself :D
Yes. The MAF sensor is actually a mini computer. All of the conversions are done inside of it.
All computers need a main power and ground to work. So you can think of the 12v feed and ground on this MAF sensor as the same thing. IT is actually a MAF module.
you never over killed a single video on your channel cause your knowledge is priceless
thanks so much!
I have seen a bad MAP or MAF cause poor mileage,transmission issues, and even a no start. Good video.
Thank You Very Much. I just purchased a 2000 Corolla and after changing the spark plugs didn't fix the problem I guessed it was the oxygen sensor. So $85 dollars later I was feeling a little worried when I still had the same problem and not sure where to go. Your video saved me a lot of time, worry, and most likely money. Just removing that little bit of dirt made all the difference. Thanks for the video!
After clean the maf sensor the idle is fix and running good for a test drive but for second test the p0300 came back but is not misfire a lot LTFT --10 on both bank.. thank you for the time I know your are working hard every day. god bless you..
thanks man! keep at it bro you are at that threshold now where great things happen. experience is so critical isn't it? i have so much to learn still too. it never stops
@MrMratni Thank you very much and no problem. I am glad you liked it.
awesome diagnosing!!
just bought a 2001 Corolla with code PO171 thinking O2 sensor, reading some tech found more likely a dirty MAF - this video is awesome! I not only see the how and why it makes sense - but your explaination helped me understand data I have been logging on a racing V8 car as well with fuel problems.
this is internet at it's best, thanks for sharing!
Thanks alot! My hilux has been missing and hesitating for weeks, I had done some AFM testing and given it the all clear. Your video made me go back over it and sure enough, it was filthy. Quick clean and it's back to normal. I was just a couple of days to taking it to a workshop and probably copping a $500 bill! Love your work!
This info is absolute gold! Best diagnostic videos on the web hands down. I highely recommend the ebook people, I will be buying the lecture videos also. Thanks for the wealth of info paul, keep up the good work!
this video is not for amatur mechanics. It is accurate and packed with infomation for trained professionals who may have missed or are trying to deepen there knowledge. You have to watch it a few times to gather all the info and check out other videos and spend some time studying. Great and accurate video as usual. thanks paul.
Thanks mike r!
Good question, as for the vacuum leak issue. I have never seen that effect the baro calculation. Also after cleaning the MAF, you have to reset the KAM or disconnect the battery for awhile to clear the baro calculation in memory.
@chief455 Thats great! Thanks for your response. It helps to know that this video was clear and useful. It keeps me motivated to keep filming more.
great videos scannerdanner lots of good info,i just graduated from ATS school in sacramento and i am getting ready to test soi am reading all my books and watching all your videos very helpful thankyou.
Had an exact same problem on a 2001 Yaris and this gave me confidence to confirm my repair after I had cleaned the MAF, great videos!
I've been watching your videos for years and have been a technician for 30 years.. When i started to be really interested in MAF sensors i was seeing a hell of a lot of hot film style here in Europe.
El Paso TX right here... Keep it up ScannerDanner... this channel is music to my ears...
@GamingJediPwns you are mistaken on that comment. this style of hot wire maf is not damaged by the cleaner i used. its just a heated resistor with a glass covering. I've been cleaning them this way for 15 years with ZERO comebacks
The IAT is a thermistor and the "cold wire" is possibly a thermistor, but the "hot-wire" is a resistor. (technically a thermistor is a resistor)
Thermistors are generally used in voltage sensing circuits. MAF circuits measure the current flow needed to maintain hot-wire (heated resistor) temperature above ambient, then convert this to an electrical signal (analog or digital) that is proportional to the current flow and therefor in-coming airflow
This is the best MAF diagnostic video. All your videos are very informative, thank you so much sir for uploading..
Cheers man. Just recently bought a Celica GT-S and suspect I'm having almost the exact same issue. Replaced Spark Plugs and put injector cleaner in, didn't help much with my lag. Figured it was a MAF Sensor issue. Going to clean it this afternoon and get back to you :) This vid helped a lot, cheers!
@import0408 I hesitate to say all but most yes. The older vane airflow meters on some of the cars had high voltage at idle and it would drop under load, so opposite of the others in operating range.
Thank you so much. I truly appreciate the support
Awesome video, thank you for uploading! Always good to see the entire process explained properly, instead of just jumping to the fix. Very pro.
I'm ok with the initial drop lean on a rapid snap to WOT(sometimes you see that, sometimes you don't). Just make sure it stays rich the entire time after that.
thank you , it was perfect answer, it clarified every question was in my mind.
you know Paul I talked to my snap on dealer I made a letter for snap on he said he was going to handle to some one in chart there for diagnostic I told the guy you are teaching us how to use the verus and how to test the sensor with the tool on real vehicles problems I told the dealer guy you should get some credit for that I hope they do some thing you really deserve it.
These videos r really valuable information. This was six years ago! Thank u Paul Danner!!
This is so awesome man. My 98 camry was running lean base on my fairly new plugs having ash like build up and power reduction at increased RPM. found you video and it surely help me to understand a bit more of whats going on. dont have all your test equipment but now know the expected output voltage from the sensor when I do my volt meter test.
As an electrician I know the benefits of the right test equipment. great job on the video.
@mechanic4yourcar Thank you! With your creditials that means alot. I am glad you liked it. Thanks for watching.
don't worry about the STFT with the engine cold and in open loop. The numbers are irrelevant.
So do you have positive or negative fuel trim numbers when warm. mainly the LTFT is what I need
i believe that is an analog type maf sensor and the signal should read more than 4 volts at wot redline. with a dmm you will need to drive it to see that number as the meter isn't fast enough for a wot snap test in park. You could also look at the stft and see if it tracks positive with a rise in the maf signal, this would also indicate a maf problem.
Great diagnostic strategy, Using just the scanner to narrow down on the fault, that's a show of in dept knowledge on auto-diagnostic.. Thumps Up......
Thank you Kevin!
@03mazpro a dirty mass air flow sensor will not cause a catalytic converter trouble code. if all you have is a converter code and no exhaust leaks then you need to replace it. as for cleaning the mass air flow sensor as long as it is the style in this video then it is cleanable and brake or carb cleaner is fine
@JohnMcClane99 Awesome! I'm glad it worked out for you. Extra money in our pockets this time of year is a good thing.
Low MAF grams per sec at WOT, also low voltage during a snap while we were testing it directly under the hood. These were the clues that the MAF was the problem and not fuel pressure.
Thank you Paul for this, my ‘11 Cruze LS has P0171 code. Will be testing this method on my way to work tonight.
@contagiousFX What numbers? Fuel trim should be +/- 10% MAF grams/sec and frequency will depend on year and engine size to name a few. For most of the GMs I look for at least 150 gram/ sec at WOT and a frequency of over 8500HZ, Idle would be around 2.3-2.4khz. But again there are variable.
The car most likely also had some fuel trim trouble codes too. If the MAF is reporting the wrong airflow the a/f ratio will be completely wrong and this can cause misfiring. Usually this is accompanied by lean or rich trouble codes as well.
Does the sensor under report or over report when it’s dirty?
I get that the O2 shows lean and it’s dumping fuel, but it’s only reading lean because of what the maf is reading. So does that mean the maf is over reporting airflow?
If that’s the case why are airflow numbers greater with the clean sensor?
I’m just confused as to how the MAF causes the O2 to misread if the calculated air was less with the dirty sensor?
Am I misunderstanding and the maf is under reporting and it’s fueling for what the MAF thinks is passing but the actual air charge still passes and leans out the mixture the MAF thinks it is dealing with? Then that causes the pcm to infinitely rich the mixture because it will never record absolute air flow
@@DDR233 a dirty MAF will under report airflow under loads. Some will over report at idle only, but both types will under report under loads. This causes the base fuel map to be skewed as the engine load is being under reported too.
So positive fuel trim numbers result. Positive trim numbers does NOT mean rich!! It is a rich command caused by a lean condition.
Absolutely fabulous video. I can't imagine this video being done better. Great info and great presentation.
Yes
A MAF DTC with good MAF sensor usually sets a “range/performance” code and may be caused by the following:
TPS problem
Vacuum or air intake leak
Oil cap or dipstick problems
PCV system leaks
Dirty/plugged air cleaner
clogged exhaust
I've seen them set for only one bank but if you look at the trim numbers both banks are affected. It just flags one side because it is worse than the other. (sometimes)
Thanks! I was having trouble getting a clear shot with this design. Sorry about that
Did you do the resistance check I showed in part 2 of the one video? This is your only option without a scope, unless you get lucky and the shorted injector is one of the two injectors you can get to without removing the intake.
There are other causes of this condition on your car, but lets do a resistance check on the injectors first.
yes i did the resistance check and found one injector at 5 oms and 3 others at around 9 ohms so i did have shorted injector ,was my starting issue.hey thanks alot for your help i was going crazy with this hard to find issue for 3 weeks .thanks again for sharing knowledge i saved alot of money doing it myself. gm 2.8 fixed good day
great info as always...love the ending with long and short term relearning....bob
Thanks to Paul danner I can't look at vehicals the same anymore. The book he put out is worth every $ your pay. My life has realy changed thank you paul. I can't wait to see more videos and I'm really hoping you put out an other book I know there is more you have discovered to teach us. I soon will have my L1 certificate. Thanks to you again. Keep up all your doing its great.
All new stuff right now is in the form of video lessons on my Premium channel. I may write another book someday, but for now, come join my classes! Thanks
@lucky51762 Sorry, it was a snap-on verus and not all MAFs can be cleaned. Just the hot-wire type. Thanks for your comment.
Just subscribed to Your account,Your uploads are excellant,have learned so much in a short space of time.I will definitely buy your E Book,I've never had anyone to learn much from about diagnostics so i'm very impressed with Your information and delivery which is easy to understand.keep up the Good work from Paul in Ireland
@lesbirel91 A dirty MAF is not the only cause of a lean exhaust trouble code. If you have my book check out Section 5 page 5. The list on this page address the most common causes for P0171 and P0174 DTCs
There are two grounds because the PCM MAF signal circuit actually gets its ground through the MAF sensor.
So one ground is PCM to MAF and the second ground is MAF to the block.
If the MAF to the block ground is bad, BOTH grounds will be bad.
No 5 v ref. on this design.
typically not but it is possible. you need to start by checking your fuel pressure and checking for a ruptured fuel pressure regulator diaphragm
Thanks man! i just bought your book, this is my first video from it, thanks man!!
Hope you enjoy it! Thank you so much!
if the o2 is switching before the wot run then it is not an 02 problem. it is a fuel delivery problem. low fuel Psi and dirty MAF are the top two.
a severe misfire can also cause this
Superb video and very informative. To get rid of glare on your screen get a polarizing filter for your camera, cheers.
If you're reading the values from a diablosport predator, I believe the output for the "baro hz" isn't the actual hz, its that number converted to "Hg based on a table. So a reading of 30Hz is actually 30"Hg...or approximately sea level.
Thank you Joel!
The whole video is very good filled with good information.
Really good tutorials, keep up the good work, we need more like these.
Wow i cleaned the wrong part the whole time. I'm going to try again. thank you very much.
thank you
@Gizmopflege Thank you!
haha I actually used a fine-tipped dental pick, but don't tell anyone! A little compressed air helped too. Those wires were pretty gunked up...not to mention his airbox was full of dry leaves lol
Great Video, I can barely see 1 Thermistor (Temperature Thermal Resistor) when it was dirty at 07:30, and you can clearly see both afterword's at 08:56, Everything looks Clean, Dry, and Tight.
Excelente estudo de caso. Obrigado!!
Yes as a matter of fact. Does this have a vane type airflow meter?
You are awesome I just brought your book and send me here you're the man I'm learning a lot thank you so much
Awesome! Thank you so much!
The check engine light will set the other two lights. They are the traction and vehicle stability control systems.
Fix the check engine light and you will automatically get rid of those other lights
God dam ...this guy needs all the newer tools....scanner your the man
@RUSS16V2 Thank you very much and I will!
thanks tony!
@MJRPerformance Thank you!
Thank you for your response , so it receive 12 volts external the maf and some way inside the maf it is converted to 5 volts Out put sensir signalto PCM is that rigth?? Because on snap throttle I saw about 4 volts. Thank you , you are a great teacher
Paul, MAF air flow depends on HP. The 2000 Toyota has 125 HP so max air flow will be about 110 gm/sec. An E39 M5 has 400 HP so max air flow is 350 gm/sec.
not a dumb question.
you cannot use the downstream sensor the same way because the cat catches and stores oxygen. there is some diagnostic advantage though but it is not used the same way. check out my o2 fixed lean case study
If it was a 2 bank system then yes, a dirty MAF would affect both banks. But this is only a 1 bank 4 cylinder engine. Bank 2 doesn't exist.
Great question though, it means your thinking!
This very informative. Thanks! Have a VW and waiting to get my OBD II Pro to get real data
holy Crap. that could be the lowest baro reading I've ever seen on a ford. it should be running ultra lean with that number. you have any codes
Great and thorough video
Great test i like the veruss min max capability however i always use my dvom when reading o2 signals ive just been burnt to much with false readings but overall that was a great test got straight to the root without even having to check fuel pressure
nice thanks bro
I believe it is a hot wire type but you should pull it out and inspect it first
There are other causes of those lean exhaust codes. Sounds like you need to take it to a competent mechanic. It doesn't matter if he is an aftermarket guy or a dealer guy. Go to iATN and search for garages in your area. If they are iATN members you have a better shot at a good tech.
Close. Low fuel pressure will also be an under load lean condition just like a dirty MAF
Sweet man, nice job!
Good explanation, thanks!
Yea, I know I should take it off as I am not showing proper safety procedures with it on. I am super careful of where I put my hand and truthfully I would rather take the chance than take my ring off. It is sacred to me. (I do take it off if I am reaching my hand near a starter motor or alternator that I cannot see very well)
that build up is call insulation and insulation traps heat. air coming in is designed to cool sensor but good insulation wont allow that. great case study.
No the hissing is tank vapor psi not fuel psi and will have nothing to do with your lean exhaust code. An EVAP code maybe but not a lean exhaust.
Dan , if you know you have a good MAF for sure. Is it possible for the computer for give a MAF fault code on a scan tool , even with a good MAF sensor . 1999 olds intrique 3.8. thank you
I am not sure. I know some guys use this initial spike to determine if the MAF sensor is dirty. I am just not familiar enough with the procedure.
Danner,great channel buddy. As a hobby mechanic, and a guy who mostly tinkers with *gasp* carbs, I can only dream of having the diagnostic tools and knowledge that you've acquired over the years. But I appreciate you showing us how it really should be done by good, experienced mechanics.
Quick question for ya. On my 96 Mustang I had a P0172, if I remember correctly. I chased it for months with new vac hoses, sensors, etc. Ended up being badly arcing plug wires. Does that sound right to you?
I've had this issue before and although I fixed it with a clean, the sensor eventually failed down the line. I just prefer to replace the sensors now.
Higher than normal Co means the car is running rich. If you have my eBook, Section 5 page 4 gives a list of causes of richer than normal conditions. Here is the list:Higher than normal fuel psi
Ruptured fuel psi reg. diaphragm
Leaking fuel injector
EVAP purge problems
ECT or IAT sensor problems
MAP/BARO or MAF sensor problems
EGR valve stuck open at idle
Fuel contaminated oil
Head gasket leaking causing coolant contamination of the O2
Jumped timing chain/belt
The VVT-I configuration did not exist on the 98 Corolla, it started on the 00 model year. Check your fuel pump pressure. Had the same problem on my 98 Corolla at around 200,000 miles. New fuel pump cured the problem.
haha, Paul's voice sounds like it's straining sometimes, but that's just b/c he's passionate about his work and wants you to hear over the shop noise.
hi there mr. danner great videos BTW. i just have a quick question for you. i have a 2000 volkswagen passat with multiple misfire, the mechanic change the MAF sensor and run like a charm again.now how could a MAF sensor trigger a multiple misfire?
thanks scanner danner keep up the work
I don't think there was a problem at all with the scan data. I think this was simply a small engine that doesn't "breath" the same amount as other engines do. Remember every car is different as far as what peak grams per sec will read.