@aeligos It creates a vacuum leak which throws fueling out as the air flow sensor doesn't know that unmetered air is going into the engine. So in other words the engine gets air but not enough fuel as the computer doesn't know how much to add.
Thanks Duane! Nailed it in part 2. The O2 sensor not moving and the STFT not readjusting as a result was what I based my decision on. Knowing that the O2 sensor is the only thing that makes the STFT adjust is key knowledge. I did not know that if you pulled the plug on the sensor the computer substitutes a value of .5V! Thank-you very much for that useful bit of info as it may come in handy for future diagnostics. You're the man! Please keep the video's coming. This interactive format is great!
I wish I had you as my mechanic. I am pretty good at diagnosing my car problems, and have fixed many vehicles, but don't have the fancy computers to help me find the problem. Today you NEED computers to fix cars. Thanks for all the great videos. We need people like you to teach us the technology, as is changes rapidly.
I really appreciate the methodology used here. It's great to advocate such a thorough and meticulous investigation, to find the true problem, and not to guess or as you say, "throw parts at it". Thanks for a great series of videos!
@meiermotorsports The rear O2 sensor has no influence on fuel control. The reason it's there is to monitor catalyst efficiency, although I have compared front and rear O2 sensor readings on the same bank to solve a problem just like the one that was presented in this series before.
I was right, and I knew straight from the first video!!! Another way to test the O2 sensor would be to remove it from the vehicle, and grab a multimeter and monitor the output voltage as you apply and remove heat from the sensor. I think Duane has already covered this methon in a previous video. Great stuff Duane!
yah, thats why im a truck driver. I assumed the info on the scope was accurate and thats always a bad thing. well thanks again for all your videos I really enjoy watching them and there more fun to watch than anything on tv.
good job this i show people actually get taught unlike alot of the auto or mechanic classes that just run you through stuff without explaining how things actually work
I gotta admit, I have been checking for this video to post every chance I could. It really got me thinking. By the way, I got it right too. Thanks for taking the time to teach us this hard won knowledge. You're truly a gifted teacher.
wow, I was wrong at part 1 and part 2, good video Duane and proving the point that gathering information is essential to an accurate diagnosis and repair.
Great video please do more of these. I like these better than the normal videos because I get to make my own guess and find out if im right or wrong and why
This is why the engineers developed a misfire counter that would trigger that would signal the PCM to ignore the O2 sensor when there is a sufficient amount of misfires. I am sure you are around my age and can remember the early fuel injected cars that would come in with a miss and the O2 sensor was triggering lean so the ECM would leave the injectors on longer, dumping even more fuel making the problem worse.
@amjadama for the last time... O2 sensor is reading lean because sensor is stuck to 0 - 4 mV but you have P0300 random misfire and that's why it smell rich but the O2 sensor is not reading properly that's why he can't adjust to rich mixture cause by P0300 and that's why O2 sensor is still reading lean
@TheRick2130 yes but i was actually referring to what Duane said at 0:37, that is if the sparks were not firing and fuel and air were there and unburned, how would that create a rich mixture since most of the oxygen that got inside didn't burn, and the O2 sensor reads the flow of oxygen so why it won't read lean instead of what Duane said it will read rich?...or could it be that the oxygen will burn fully but it will burn unefficiently and so it will read rich coz there is still fuel?
wow i learned something new today. i had a Corsica that ran extremely rich.. i changed the fuel pressure regulator, egr, and all 6 injectors. stil ran the same so i sold it. i never thought once about checking the o2 sensor...smh
An ignition misfire ( coil or spark plug ) will cause a LEAN condition. Pcm will be adding fuel, sensors do not detect unburnt fuel only ignited mixture. You still have all that unburnt O2 in the exhaust.
@meiermotorsports Maybe I should've worded my comment a little better. The rear O2 wouldn't have any effect on how a car runs, so if it had misfires, it wouldn't be cause of the rear O2. I mentioned fuel control since the front O2 influences fuel control. It's really doesn't matter if the rear O2 sensor is a little low or high, as long as it's reading is a lot different than the front O2 reading. It's pretty rare that a rear O2 goes bad cause the converter protects it from a lot of bad stuff.
@dmorley100 Actually on some vehicles the computer uses the rear o2 senors to help with fuel control. Not supposed to happen, but because of some engineering flaw it can and will happen. I think this is on some European cars, not 100 percent sure. Someone help me out here.
@1PossumJenkins Interesting you say that... How would the computer know that the O2 sensor is really bad or that the problem is not a REAL lean condition caused by a faulty engine?
Just as I had stated on last post... A vacuum leak would affect BOTH banks yet only bank 1 is reporting lean, thus not suspected as a vacuum leak. And simply unplugging suspected O2 sensor would default to .5 volts and problem would go away. Simply reading the evidence and a little knowledge and some " been there done that " will help figure this out. Knew it wasn't secondary ignition due to that fact it runs fine when cold. Bad ignition would run poor ALL the time. I would still suspect cataly
I say that the engine needs a complete tune up also the map sensor needs to be replaced,the fuel filter could be going bad. TheO2 sensor needs to be,replaced.
I diagnose problems almost EXACTLY like this guy does. Too bad customers aren't willing to pay techs by the hour to fix their electrical problems. "OMG you mean my intermittent battery drain might take more than $100 to fix? f-that, I'll buy a battery jump box". So while this methodology is great, chances are techs in the real world don't have time to be Sherlock Holmes on Oxygen Sensors and what not because most customers aren't willing to pay for accuracy.
Brilliant series, Duane. I didn't see how you hooked up your scope. Did you back-probe the O2 sensor leads, or is that data available by tapping into the PCM or OBDII port?
My wife and I recently got Netflix and found that a very nice escape for our evenings. However, after watching Netflix I'm on the computer watching your videos on RUclips. This 3 part series was better than Perry Mason, NYPD or CSI rolled into one. Evidence and knowledge got it, Sherlock!
I wonder why a normal OBD2 code reader didn't come up with a code for replacing an O2 sensor? I would think it would have see that defect without going threw all that.
DUANE I HAVE QUESTIONS: 1- Why is O2 Sensor 2 reading the same like sensor 1 was?? 0-4 mv?? 2- How does this affect the car at WOT?? doesn't the car ignore the O2 at WOT and go into an open loop? so basically the O2 sensor should not affect it at hard acceleration, am i wrong or what? 3- Since O2 sensor reads the flow of oxygen, then when its unburned doesn't it mean that even there is lots of fuel then oxygen exists so it wont read rich? PLEASE ANSWER THOSE QUESTIONS... AND THANK YOU A LOT!
I am glad i thought O2 sensor faulty before part 2 and then part 2 confirmed it and the only other thing i would have looked at was vacuum pressure. Though, unlike in the video, i wouldn't have the tools to check the voltage to the O2 sensor so i would probably end up sending the car to a repair shop if this happened to me. Still glad i was right!
how would you diagnoses this without a computer? my guess would have been the EGR, I would have been wrong,because I don't have a diagnostic computer. should I have pulled the connector off the 02 sensor first? then see how it runs,then go from that point? thanks for the great video!! I;m just a do it your self er working under the oak tree? I have a OBD2 scanner with live data, however it is not a expensive on with graphs and what not, how would I diagnosis a problem like this with that machine
these interactive videos were a great idea. i really enjoyed them and as with all your videos, i learned something. for me, the lesson here was that you need to take a logical approach to troubleshooting and look for evidence as apposed to the "shotgun" approach or just throwing parts at a problem.
The definition of misfire is the absence of combustion. A misfire on an engine where the oxygen sensors are working will report a lean condition on the scan tool. The reason is simple: No combustion means the oxygen is still present; the oxygen sensor cannot detect hydrocarbon, it can only detect oxygen.
@TheRick2130 it seems you don't get what i am saying!!!! if the O2 sensor was OK, and the problem was a bad spark, then the mixture will NOT burn correctly so the oxygen will still exist and then Duane said it will read rich (again supposing O2 sensor was OK) so my question was: how it will read rich since oxygen is still there coz it didnt burn so how is reading rich possible when an O2 sensor reads only the flow of oxygen and doesn't care for how much fuel is there!!!!
Great info,love it !!! My chev blazer 01 s10 4.3L v6 has same problem. my cheap code reader say upstream o2 is bad and maf replaced both and no fix engine still shakes and hard to start. what to do now???? gear head Stan the man.
@clcautotech: 02 sensors sense oxygen not fuel you're correct but so is Dwayne. if you have a lean condition and the 02 sensor senses too much oxygen it will keep adding fuel so will make it a RICH misfire, ya'll understand that?
Great series.I was wrong in my thought in what was wrong.I thought it was an intake leak of some type but after seeing this last part I understand now why it would make the car run that way. I learned something very valuable today. I need to get a good scan tool. I just thought intake leak of some type because of the extreme lean condition and the computer dumping fuel as much as it was to compensate. Do you think that my way of thinking was bad? Even though I know the real problem now.
Forgive my ignorance on this . Did the engine have a left and right bank O2 sensor? Why didnt the ecm recognize and set a code for bad O2 sensor if it wasnt giving voltages in the correct parameters?
@amjadama "how would that create a rich mixture since most of the fuel mixture go inside didn't burn?" first what is product of combustion is CO2 which mean if is not burned you still have O2 in it! and second O2 sensor reading LEAN not rich! he said if your coil/sparkplug is not firing you will have rich mixture. but the O2 sensor stuck at 0 - 4 mV which will cause lean mixture
The only thing that Duane did that I didn't state was to check that sensor for the ability to read lean or rich before unplugging it.... I just skipped right to what I would do first. And @sbaker... Your are correct, given that engine runs ok when cold would rule out all mechanical issues as well as EGR. MAC Tools carries a nice and cheaper code reader that does live data made by Launch for around $200... But that Verus is a bad dude! My shop has one and it does almost everything but red tailpi
@gratefuldead42022 Well, I guess that depends on the intelligence of the engineers programming the computer and on the amount of read only memory (ROM) space available to the computer to make those kind of interpretations.
@ktumbleweed Actually, now that you mention it, I think you're right. It's on a few fairly rare vehicles that they do this with. I know you mentioned European vehicles, but I think a rear O2 sensor has some fuel control influence on a Cadillac XLR as well.
@MrSoundQndn it will run but it will not be really fine because it will be "guessing" how much fuel to add using tables in its ecu/pcm so the burning process will not be ideal or perfect and the gas mileage will be bad and maybe with time it will damage the engine because some misfires may occur due to excess or few fuel the ecu/pcm provided based on "guessing"
This man is a real mentor and a great teacher to all who wish to learn the right way/ he has patience and explains things in such a way that anybody can understand / keep up the great work sir
@gratefuldead42022 well there is sense in what you are saying.... what is making me ask all those questions is that the sensor generates voltage using the ratio between oxygen in exhaust gases and oxygen in atmosphere as its reference, u can check this in wikipedia under oxygen sensor in the part of "operation of the probe"... i think i go it, using atmosphere reference it knows if the oxygen left in exhaust gas is sufficient for burning all the fuel or not hence adjusting the fuel
@qloopp the verus at 3.14 and 3.22 minutes in part 2 says HO2S1 meaning Heated Oxygen [O2] Sensor Bank1 and HO2S2, Heated Oxygen [O2} Sensor Bank2. The normal format for obd 2 is as follows. Heated oxygen [O2] sensor then Bank number followed by sensor number. In the example you cited the sensors displayed are bank one [ 0 to 4 mv] and bank two oscillating between [17 to 30 mv] This has confused me in the past. Its heated oxygen sensor HO2s then bank number, then sensor number
@studly48150 a rich condition could be caused by a number of things, id start by checking the ignition, plugs/leads/distributor pack, it could also be a central port fuel injection leak (if your vehicle uses this system), Dwane once showed a video of a fuel pressure regulator that was leaking inside the inlet manifold. Im not sure if a 1988 engine uses fuel injection (its a bit before my time). A lack of air flow can cause a rich condition so check out your air intake system.
I enjoyed your video but I must point out something you said that was incorrect. When your cylinder is not firing and raw fuel and air are being pumped down the exhaust you are NOT going to read rich on your oxygen sensor, just the opposite . The oxygen sensor reads the amount of oxygen, not fuel. When you have combustion the oxygen in the cylinder is depleted and when there is a misfire and there is no combustion you are pumping oxygen into the exhaust and the O2 sensor reads that as a lean con
@aeligos It creates a vacuum leak which throws fueling out as the air flow sensor doesn't know that unmetered air is going into the engine. So in other words the engine gets air but not enough fuel as the computer doesn't know how much to add.
Thanks Duane! Nailed it in part 2. The O2 sensor not moving and the STFT not readjusting as a result was what I based my decision on. Knowing that the O2 sensor is the only thing that makes the STFT adjust is key knowledge. I did not know that if you pulled the plug on the sensor the computer substitutes a value of .5V! Thank-you very much for that useful bit of info as it may come in handy for future diagnostics. You're the man! Please keep the video's coming. This interactive format is great!
Excellent education, thanks
wow great videos
thanks for sharing your knowlege
this proves that knowlege is POWER
THANKS
Good video. Please have more of this series. Thanks
I wish I had you as my mechanic. I am pretty good at diagnosing my car problems, and have fixed many vehicles, but don't have the fancy computers to help me find the problem. Today you NEED computers to fix cars. Thanks for all the great videos. We need people like you to teach us the technology, as is changes rapidly.
I really appreciate the methodology used here. It's great to advocate such a thorough and meticulous investigation, to find the true problem, and not to guess or as you say, "throw parts at it". Thanks for a great series of videos!
nice doctor Dwanye! I diagnosed this from my den thanks to the great job on the video. keep them coming because they all are, shall we say, PERFECT!
@meiermotorsports The rear O2 sensor has no influence on fuel control. The reason it's there is to monitor catalyst efficiency, although I have compared front and rear O2 sensor readings on the same bank to solve a problem just like the one that was presented in this series before.
Awesome videos
Excellent direction. Very good video.
nice wway of proving the problem and repair, thats great knowledge thanks for sharing
Great video series
I love it. I learn a lot thanks guys
Great Video series!! Thank you for taking the time to make them!
Great way to get us invoved I really enjoy it thanks Duane.
thanks
I was right, and I knew straight from the first video!!!
Another way to test the O2 sensor would be to remove it from the vehicle, and grab a multimeter and monitor the output voltage as you apply and remove heat from the sensor. I think Duane has already covered this methon in a previous video.
Great stuff Duane!
As always I have learned from your videos. Thank You
I loved these videos the interaction part really makes you think. I love to releaen stuff that I forgot. Thank you for the video.
Great video series !
i was way off. these videos were a really great idea. and there a great teaching tool. i hope to see many more like them.
u guys are amazing thanks...
yah, thats why im a truck driver. I assumed the info on the scope was accurate and thats always a bad thing. well thanks again for all your videos I really enjoy watching them and there more fun to watch than anything on tv.
@sbakar It was thinking that the lean reading was because of a mechanical failure and not a sensor.
Great job
good job this i show people actually get taught unlike alot of the auto or mechanic classes that just run you through stuff without explaining how things actually work
absolutly fantastic videos, thank you for the knowledge
I gotta admit, I have been checking for this video to post every chance I could. It really got me thinking. By the way, I got it right too. Thanks for taking the time to teach us this hard won knowledge. You're truly a gifted teacher.
wow, I was wrong at part 1 and part 2, good video Duane and proving the point that gathering information is essential to an accurate diagnosis and repair.
@aeligos
Because the motor would suck a lot more air in through the booster line.
Simply outstanding 3-part video you have given us, please please I need to learn more.
Great video... im glad and happy you guyz helping us saves money on fixing to shops and we can fix our own car.
Thanks Detective Duane! Can't wait the other videos!
this is a good video for the aspiring mechanic and even a license mechanic! hope they get the message that don't just change the part :)
Great video and a good way to get the viewers involved... If I was in your area you would be my one and only mechanic...
Great video please do more of these. I like these better than the normal videos because I get to make my own guess and find out if im right or wrong and why
Fantastic vid as usual, I would have never been able to guess at all before I started to study your videos. Hope you have more of the same.
Great video and series, hope you make more of these! Very helpful!
This is why the engineers developed a misfire counter that would trigger that would signal the PCM to ignore the O2 sensor when there is a sufficient amount of misfires. I am sure you are around my age and can remember the early fuel injected cars that would come in with a miss and the O2 sensor was triggering lean so the ECM would leave the injectors on longer, dumping even more fuel making the problem worse.
@amjadama for the last time... O2 sensor is reading lean because sensor is stuck to 0 - 4 mV but you have P0300 random misfire and that's why it smell rich but the O2 sensor is not reading properly that's why he can't adjust to rich mixture cause by P0300 and that's why O2 sensor is still reading lean
great video series i hope you do more in the future!
Excellent !! More "What's wrong with it" videos, Please!!!!!
@TheRick2130 yes but i was actually referring to what Duane said at 0:37, that is if the sparks were not firing and fuel and air were there and unburned, how would that create a rich mixture since most of the oxygen that got inside didn't burn, and the O2 sensor reads the flow of oxygen so why it won't read lean instead of what Duane said it will read rich?...or could it be that the oxygen will burn fully but it will burn unefficiently and so it will read rich coz there is still fuel?
I was thinking vacuum leak, but you had the right order of steps. Verify that the information you have is accurate and not the result of faulty parts.
thanks for the great video and Informative too..good work guys>>
I knew it lol.
Thanks you made my day!
Great video, i hope to see more like this! :)
You're a great mechanic Dwayne, hope one day I can be like you. You don't throw parts , you narrow in the problem.
Good video..
@dmorley100 never said anything about the rear o2 and fuel control. the rear o2 signal looked low. possibly going bad or just not yet warmed up yet.
Thank you very much for all the trouble taken to record this.
I WISH I HAD FANCY EQUIPMENT LIKE THAT :(
wow i learned something new today. i had a Corsica that ran extremely rich.. i changed the fuel pressure regulator, egr, and all 6 injectors. stil ran the same so i sold it. i never thought once about checking the o2 sensor...smh
An ignition misfire ( coil or spark plug ) will cause a LEAN condition. Pcm will be adding fuel, sensors do not detect unburnt fuel only ignited mixture. You still have all that unburnt O2 in the exhaust.
@meiermotorsports Maybe I should've worded my comment a little better. The rear O2 wouldn't have any effect on how a car runs, so if it had misfires, it wouldn't be cause of the rear O2. I mentioned fuel control since the front O2 influences fuel control. It's really doesn't matter if the rear O2 sensor is a little low or high, as long as it's reading is a lot different than the front O2 reading. It's pretty rare that a rear O2 goes bad cause the converter protects it from a lot of bad stuff.
well done
COOL
@dmorley100 Actually on some vehicles the computer uses the rear o2 senors to help with fuel control. Not supposed to happen, but because of some engineering flaw it can and will happen. I think this is on some European cars, not 100 percent sure. Someone help me out here.
yah, thats why im a truck driver. I assumed the info on the scope was accurate
Wouldn't think a bad O2 sensor would effect the engine THAT much. Good to know.
Even though I was wrong :( I so enjoyed your Vids and today I learned something new. Nice work Dwayne
@1PossumJenkins Interesting you say that... How would the computer know that the O2 sensor is really bad or that the problem is not a REAL lean condition caused by a faulty engine?
It appears the scanner was very helpful after all. That’s how you acquired most of your evidence.
Just as I had stated on last post... A vacuum leak would affect BOTH banks yet only bank 1 is reporting lean, thus not suspected as a vacuum leak. And simply unplugging suspected O2 sensor would default to .5 volts and problem would go away. Simply reading the evidence and a little knowledge and some " been there done that " will help figure this out. Knew it wasn't secondary ignition due to that fact it runs fine when cold. Bad ignition would run poor ALL the time. I would still suspect cataly
great video.....nice mellow learning music lol;)
I say that the engine needs a complete tune up also the map sensor needs to be replaced,the fuel filter could be going bad.
TheO2 sensor needs to be,replaced.
I diagnose problems almost EXACTLY like this guy does.
Too bad customers aren't willing to pay techs by the hour to fix their electrical problems.
"OMG you mean my intermittent battery drain might take more than $100 to fix? f-that, I'll buy a battery jump box".
So while this methodology is great, chances are techs in the real world don't have time to be Sherlock Holmes on Oxygen Sensors and what not because most customers aren't willing to pay for accuracy.
Brilliant series, Duane. I didn't see how you hooked up your scope. Did you back-probe the O2 sensor leads, or is that data available by tapping into the PCM or OBDII port?
My wife and I recently got Netflix and found that a very nice escape for our evenings. However, after watching Netflix I'm on the computer watching your videos on RUclips. This 3 part series was better than Perry Mason, NYPD or CSI rolled into one. Evidence and knowledge got it, Sherlock!
what about that rear o2. looked kinda low also. still have misfires??
love the video!!!!
Damn I was wrong. I've never had an O2 sensor cause misfires. Crazy. Good to know!!
I wonder why a normal OBD2 code reader didn't come up with a code for replacing an O2 sensor? I would think it would have see that defect without going threw all that.
DUANE I HAVE QUESTIONS:
1- Why is O2 Sensor 2 reading the same like sensor 1 was?? 0-4 mv??
2- How does this affect the car at WOT?? doesn't the car ignore the O2 at WOT and go into an open loop? so basically the O2 sensor should not affect it at hard acceleration, am i wrong or what?
3- Since O2 sensor reads the flow of oxygen, then when its unburned doesn't it mean that even there is lots of fuel then oxygen exists so it wont read rich?
PLEASE ANSWER THOSE QUESTIONS... AND THANK YOU A LOT!
I am glad i thought O2 sensor faulty before part 2 and then part 2 confirmed it and the only other thing i would have looked at was vacuum pressure.
Though, unlike in the video, i wouldn't have the tools to check the voltage to the O2 sensor so i would probably end up sending the car to a repair shop if this happened to me.
Still glad i was right!
how would you diagnoses this without a computer? my guess would have been the EGR, I would have been wrong,because I don't have a diagnostic computer.
should I have pulled the connector off the 02 sensor first? then see how it runs,then go from that point?
thanks for the great video!! I;m just a do it your self er working under the oak tree?
I have a OBD2 scanner with live data, however it is not a expensive on with graphs and what not, how would I diagnosis a problem like this with that machine
nice your a good tech
these interactive videos were a great idea. i really enjoyed them and as with all your videos, i learned something. for me, the lesson here was that you need to take a logical approach to troubleshooting and look for evidence as apposed to the "shotgun" approach or just throwing parts at a problem.
The definition of misfire is the absence of combustion.
A misfire on an engine where the oxygen sensors are working will report a lean condition on the scan tool.
The reason is simple: No combustion means the oxygen is still present; the oxygen sensor cannot detect hydrocarbon, it can only detect oxygen.
@TheRick2130 it seems you don't get what i am saying!!!! if the O2 sensor was OK, and the problem was a bad spark, then the mixture will NOT burn correctly so the oxygen will still exist and then Duane said it will read rich (again supposing O2 sensor was OK) so my question was: how it will read rich since oxygen is still there coz it didnt burn so how is reading rich possible when an O2 sensor reads only the flow of oxygen and doesn't care for how much fuel is there!!!!
Great info,love it !!! My chev blazer 01 s10 4.3L v6 has same problem. my cheap code reader say upstream o2 is bad and maf replaced both and no fix engine still shakes and hard to start. what to do now???? gear head Stan the man.
@clcautotech: 02 sensors sense oxygen not fuel you're correct but so is Dwayne. if you have a lean condition and the 02 sensor senses too much oxygen it will keep adding fuel so will make it a RICH misfire, ya'll understand that?
Great series.I was wrong in my thought in what was wrong.I thought it was an intake leak of some type but after seeing this last part I understand now why it would make the car run that way. I learned something very valuable today. I need to get a good scan tool. I just thought intake leak of some type because of the extreme lean condition and the computer dumping fuel as much as it was to compensate. Do you think that my way of thinking was bad? Even though I know the real problem now.
Forgive my ignorance on this . Did the engine have a left and right bank O2 sensor?
Why didnt the ecm recognize and set a code for bad O2 sensor if it wasnt giving voltages in the correct parameters?
i have a 88 ford ranger it is running rich , you think u could give me a place to start . new plugs and wires . Thanks . it runs good till worm .
@amjadama "how would that create a rich mixture since most of the fuel mixture go inside didn't burn?" first what is product of combustion is CO2 which mean if is not burned you still have O2 in it! and second O2 sensor reading LEAN not rich! he said if your coil/sparkplug is not firing you will have rich mixture. but the O2 sensor stuck at 0 - 4 mV which will cause lean mixture
The only thing that Duane did that I didn't state was to check that sensor for the ability to read lean or rich before unplugging it.... I just skipped right to what I would do first. And @sbaker... Your are correct, given that engine runs ok when cold would rule out all mechanical issues as well as EGR. MAC Tools carries a nice and cheaper code reader that does live data made by Launch for around $200... But that Verus is a bad dude! My shop has one and it does almost everything but red tailpi
Try a retorque on the intake if the port is leaking air that would make it run lean too and create a misfire or backfire .
@gratefuldead42022 Well, I guess that depends on the intelligence of the engineers programming the computer and on the amount of read only memory (ROM) space available to the computer to make those kind of interpretations.
@ktumbleweed Actually, now that you mention it, I think you're right. It's on a few fairly rare vehicles that they do this with. I know you mentioned European vehicles, but I think a rear O2 sensor has some fuel control influence on a Cadillac XLR as well.
@MrSoundQndn it will run but it will not be really fine because it will be "guessing" how much fuel to add using tables in its ecu/pcm so the burning process will not be ideal or perfect and the gas mileage will be bad and maybe with time it will damage the engine because some misfires may occur due to excess or few fuel the ecu/pcm provided based on "guessing"
This video really got thru to me. Thank you for reinforcing the evidence based reasoning for parts replacement, rather than hunches.
Thank you so much for sharing your knowledge and experience. Definitely makes finding my way around these computerized motors easier!
This man is a real mentor and a great teacher to all who wish to learn the right way/ he has patience and explains things in such a way that anybody can understand / keep up the great work sir
@gratefuldead42022 well there is sense in what you are saying.... what is making me ask all those questions is that the sensor generates voltage using the ratio between oxygen in exhaust gases and oxygen in atmosphere as its reference, u can check this in wikipedia under oxygen sensor in the part of "operation of the probe"... i think i go it, using atmosphere reference it knows if the oxygen left in exhaust gas is sufficient for burning all the fuel or not hence adjusting the fuel
Damn, I didn't know an o2 sensor could cause so many misfires.
@qloopp the verus at 3.14 and 3.22 minutes in part 2 says HO2S1 meaning Heated Oxygen [O2] Sensor Bank1 and HO2S2, Heated Oxygen [O2} Sensor Bank2. The normal format for obd 2 is as follows. Heated oxygen [O2] sensor then Bank number followed by sensor number. In the example you cited the sensors displayed are bank one [ 0 to 4 mv] and bank two oscillating between [17 to 30 mv] This has confused me in the past. Its heated oxygen sensor HO2s then bank number, then sensor number
Can you tell me what is the little device is in this video that adjust the propane flow?
@studly48150 a rich condition could be caused by a number of things, id start by checking the ignition, plugs/leads/distributor pack, it could also be a central port fuel injection leak (if your vehicle uses this system), Dwane once showed a video of a fuel pressure regulator that was leaking inside the inlet manifold. Im not sure if a 1988 engine uses fuel injection (its a bit before my time). A lack of air flow can cause a rich condition so check out your air intake system.
Where can I find one of those propane wands? I can not find it for sale anywhere.
I enjoyed your video but I must point out something you said that was incorrect. When your cylinder is not firing and raw fuel and air are being pumped down the exhaust you are NOT going to read rich on your oxygen sensor, just the opposite . The oxygen sensor reads the amount of oxygen, not fuel. When you have combustion the oxygen in the cylinder is depleted and when there is a misfire and there is no combustion you are pumping oxygen into the exhaust and the O2 sensor reads that as a lean con