Your comments starting at 9:11 brought this whole seminar into clear light. In the first part you override the O2 sensor signal with an external signal, to see if the PCM reacts correctly. Then, in the second test you feed the vacuum intake with propane or room air, to see if the sensor reacts correctly. I'm gonna have to make myself a little adjustable propane source like you have there. Thanks again for your effort!
That blend of practical experience and science is cool. I always thought the idea of replacing an O2 sensor without testing it was, well, disappointing. Thanks for going through this, Duane.
The guy's a master tech. The video is not misleading at all. He showed how to test the computer's response and the O2 sensors output. If you watched the video all the way through at first you would have known that. It defies logic that people post comments on these videos when they don't know what they are talking about.
Bob Kodadek, yep, trolls posting stuff they dont know, (probably never even worked on a vehicle) and saying the master tech is wrong, well...Im speechless!
@AutoTechHector thats what he said. there were 2 tests in this video, one seeing if the pcm is responding correctly (wires to the battery) and the 2nd test with the vacuum leak/propane determined if the o2 sensor itself is bad or good
I agree he is taking the sensor out of the loop and creating a maximum value negative or positive as the pcm sees it, basically bypassing the o2 sensor.
yes, you are correct, he did show how to test the computers response, but when he was doing that he was saying that he was testing the 02 senor-which he was not. also again you are correct at the end of the video he did correct himself in saying that he was testing the computers response. I was just saying that through out most of the video he was saying he was testing the 02, which he was not! I just wanted to clarify that so that some others would not get confused
@areskzc you don't need an expensive scanner, a 2 channel second hand scope (circa 50 to 100 sheckles from an online auction site) in good condition will do, all you are doing is tapping into the appropriate signal lines on a wiring harness.
Excellent lesson and tip! . I want to say that the person that states , he would just buy the new sensor cause they are cheap, did not grasp your lesson I think. May be he did , but let say he installs the new sensor and still the same problem ? Now he would have just spent money on a possible wire or computer problem..and there for is just a part changer. The object of the lesson is to test and see what the problem is before replacing parts...thanks
***** That is the object of the lesson . and I appreciate the lesson so that I can understand how to diagnose but I think Skilled Eddie , who just replaced the sensor was applying "cross discipline" problem solving
The video was good in showing appropriate ECU responses to various conditions. The quantified varying voltage signal from the O2 sensor reflects the sensor. the comments of anonymic79 and cyborgdale are appropriate.
I like this channel alot Duane gets down to the meat and potatoes of auto repair. The beginning of his videos the editorical and graphics I quess that's what call it is super pro. Man it looks like TV.
Aren't you just testing the car computer's response to the oxygen sensor, and not the oxygen sensor itself? Isn't the oxygen sensor the device that is generating the voltage on the line that you are probing? I.e., the oxygen sensor is not "reading" the voltage that you are manipulating. If you want to test if the oxygen sensor is working properly, don't you have to test that the voltage being generated on the line is varying appropriately, based on the amount of oxygen in the exhaust? Am I totally off base here?
yusuihang : I think you are right. The test by connecting the O2 sensor signal wire to ground does not verify if the O2 sensor is working properly, but verifies that the ECU is repsonding properly to the O2 sensor input. So in fact it is a test to see if the signal wire of the oxygen sensor is not shorted or broken.
He explained how fuel trim work inversely proportional to 02 sensor voltage= 02 sensor voltage near zero( 1mv)means lean condition , ECU see that raise positive fuel trim not over 10% to make 14.7 part of air to 1part of fuel ratio. In opposite, if 02 voltage go up near 1volt , fuel trim becoming negative taking fuel away due to rich condition.
I do like all your videos, just wanted to point this out because it may confuse some people if they dont really understand what was going on here. I am not knocking you at all, just wanted to clarify this, and say thanks for all your good and informative videos.
If you're unlucky and can't get the right resistance with your body, go to your local electronics store and buy a 12k and 1k resistor and a few alligator clip test leads. Connect them in series between battery plus and negative (12k to +, 1k to ground). At the junction between them you will now have about 1 volt, depending on your battery/alternator state. Measure with a multimeter to be certain.
I don't see how forcing the o2 sensor wire to gnd or 1v proves the o2 sensor is good or not. I think that is testing the PCM's response to the 2 voltages. Even if we did this test without a o2 sensor in circuit, the wave forms would behave the same way. Please comment.
I wish I had had someone like you to apprentice under before I became a licensed mechanic, wouldnt grounding/forcing to 1 volt the signal wire only test the integrity of the wiring harness and pcm's ability to respond, instead of the actual O2? I would like to see a module for wideband O2's in the future. Justin
Forcing the sensor wire to ground or to +1 volts only shows that the PCM is properly responding to the changes--not that the O2 sensor is good. Creating a rich condition with propane (and then a lean condition with a vacuum leak) while observing the sensor will show whether or not it is good. You must also test to see if it is sluggish. At 2500 rpms it should cycle 2-3 times per second for a single-port system and 5-7 times per second for a multi-port system. Engine must be at operating temp.
What good is it to add sensors to vehicles if now they are another thing you should first doubt and add to the trouble shoot? I'm no Mechanic but always here about people sending there cars in for a check engine light, sensors going bad, and costing folks $65 hr + parts + tax. Good for your Mechanic! Nice logical troubleshoot video mister.
I have had O2 sensors crash under load. Customer brings on a 93 toy truck failing smog. In bay the O2 was fine and made me test all sorts of things. Testing it on the dyno showed that the O2 was crashing lean. I had an 82 Mazda pu trowing a code 17. O2 went .450V AFTER 8 miles of freeway driving. CARB adopted testing with propane to test min/max and rise time which should be 100ms or less (most good O2 sensors will be aprox 50ms). Jim Eve's Automotive evesautomotivedotcom
Yours videos are awsome sir corecact me i am wrong when we convert a vihcles in CNG or we cut off fuel and runs car on CNG OR LPG i think the O2 sensor not much important in that case in easy way we can run a car in cng without o2 sensor
@vtecboy9 You should be able to, I have used the ELM on my diesel 54 plate (2004) UK citroen C5, and the free software shows live data, fault data and sensor data. For all it costs, give it a try.
I have a 98 dodge ram 1500 with 5.2. Pulls a po171 code lean bank one slow response. I have replaced every sensor , vacuum leaks,idle control valve, catalytic converter, gasket under throttle body. Mas sensor. Can undo battery put back on truck runs great for fifty miles engine light comes on idles up and down, gets 5 mpg and reads lean bank one code. There's nothing else to replace that I know of. Help. Short term fuel reads 32.5 long term 0.0.
thank you so much for the video. i have a question. is that torch with the propane tank home made? if not do you think its safe to cut a regular torch head off, put some tubeing like in the video and make is somewhat like yours
Here what you do. You give the customer two options. Option one toss an o2 in which will 99% of the time will fix the problem. And option two what your doing which will cost $109 an hour. No real shop is going to get that labor inventive unless there's a second visit for the same problem.
My problem with my BMW e90 320i 2009, 4 cylinder engine with 2 banks cylinder 1 & 4 is bank 1, 2 & 3 is bank 2. i am suffering from high mileage that is around 12 L/100km in the city and 8.5 L/100km highway (the standard is 9.3 L/100km in the city and 5.7 L/100km highway).I don't have any codes in the OBD II check tool, but using torque app i am getting a strange value of (fuel trim bank 1 / 2) that is +99.2% and this value is constant on idle and on high speed as well .the other fuel trim bank value (fuel trim bank 2 /2) is fluctuating normally from + to - as per the load and drive conditions. I will appreciate any help ideas.
man ...this is RIDICULOUS ... JUST TEST the O2 for switching below 0.2 and above 0.8 bad o2 sensors are in between that or are stuck mostly rich. if you have a leaky injector it will smell like it. if you have an electrical issue it will smell like it. if you have a plugged injector it will misfire clean. never touch any battery terminals with any wires ... YOU'LL BURN the ECU ... One more thing: In my OPINION people are obsessed with O2 sensors and unnecessarily replace them.
Mr. Duane, Do you think sometime in the near future we will see, 1 A/F ratio sensor per cylinder? for example, 6 cylinder engine with 6 A/F ratio sensors mounted on each exhaust runner? Over the years we have seen 1 injector per cylinder then 1 coil per cylinder (COP). Do you think this would make sense? could engines be more efficient this way? of course I suppose the pre-and post cat sensors would still be intact. anyway this is just an idea, wanted to throw it out there thanks?
Hello Real fixes, I have a lean code p0171 check engine light is always on, the cr run fine and idles fine. air/fuel sensor fluctuates between 600 to 800 down to 200. the fuel trim long term is 15 + and the shorterm fuel is -14. Check for vacuum leak engine cold sprayed water all over intake manifold , vacuum hoses , exhaust manifold, its normal. The air/fuel sensor drop to zero volts when I pulled the vacuum hose from manifold . Does a zero volt reading point to a faulty o2 sensor , its a 4 wire , on Toyota corolla 2000 4 cyl CE 1.8l. Now today I will check spark plugs and injectors, its repeated ticking sound points to both injectors and spark. spark advance on the obd tool reads 15 with a G letter . What does it mean? I have not back probe the o2 sensor because I can not find its o2 specifications on voltage drop and I don't know if its a wide band or a narrow band sensor. I cant find the fuel regulator in the engine. And I need to inspect all the vacuum hoses too. Its like being a medical doctor, I only have 150 hours of training with certificate from the 70s and learning all this analysis with fancy digital scanners can be very expensive for just a do-it yourself-er. can I use a volt meter with an amp probe together on a o2 sensor signal wire, instead of back probing? Can I use the wave screen on the less expensive OBD scanner, to see wave forms along with amp probe and wire clip , How do I set this up?
nice video , how about the down stream 02 behind the CAT . Should it be switching as often as the up stream 02 . just did a reading on my scan tool and the down stream 02 is almost a straight line with no indication of switching .car is burning a lot of fuel . 2001 Olds Bravada 4.3.
Sears - actron cp9580 plus scan tool 179.00, i am certain there are other brnad scan tools with live data reading. They do a good job no need for the thousand dollar scopes the technicians need.
so weather it be sensor 1 or sensor 2 on either ban each sensor displays ltft and stft? I was under the impression sensor 1 is only for stft and sensor 2 is ltft.
Is it really worth testing 02 sensors? I got 2 Denso upstream sensors for my truck for a total of $50. I just replace them and be done with it. If they are original and the car has a lot of miles just change them. To me the part is too inexpensive to waste time diagnosing. Now stuff like a MAF sensor that can cost up to $300 that's something you take time to diagnose.
+SkilledEddie This is really and instructional video which shows how to test the sensors. In some cars it's very difficult to get to the sensors or the parts is really expensive in which case you really need to make sure you actually need the part before replacing it.
Even here in the states my Rav4 up and downstream o2's are over $100 and there are four! Definitely worth testing! Great video! I needed to know what the individuals wires did on my 4 wire o2's.
yes, i seem that he just added an extra wire to the sensor signal wire and ground it, the other test, he creates a very small millivolt by hand resitance , he just touched one end of the same extra wire and with other hand touch batter positvie post
thank u sir, u are a good teacher, i have a grand am gt, my oxygen sensor bank1 is broken, i cant take it out , pleae tell me how to remover and installing oxygen sensor on grand am gt please, thank u sir
Hi, I need help. I have a honda accord 02 which I put a new engine. the oxygen sensor upstream was bad but I have replaced 3 Times already and still have the engine light on. what can I do.
The oxygen sensor is just that, it senses and reports what it finds. It is very very unusual that 3 of them would be bad. More likely, they are actually reporting correctly and setting a code. You would really need to test the sensor instead of just assuming it's bad. Have a tech test it. If he knows what he is doing he should be able to force the sensor to read both rich and lean and watch the scanner data. If the do indeed respond correctly when forced rich or lean then the sensor itself is good. You then would need to see why your engine is running so rich and/or lean. Hope this helps.
You are totally wrong. In LPG conversion(modern one) ECU is still regulating mixture using all sensors as normal. LPG computer is just "translating" fuel injector opening times to lpg injectors opening times.
let me see if i understand by you giving that wire 0 and 1 volts you are not forcing the sensor right? you only mimic the sensor signal ,but sensor still doing his job. I tought the 02 sensor produce "output" 0to1 volt signal not react to it ,computer reacts to it. o2 sensors read levels of o2 and report to the computer as 0 to 1 volt, sounds like 02 sensors read fuel, i tought 02 sensors were there to monitor the oxygen, rich o2 = no fuel,misfire or stuck injector
I don't think Duane properly explained what he was testing IN THE BEGINNING. He says to ground the O2 sensor output lead to ground, and then to the battery, to test the O2 sensor. That;s not correct. Doing that tests the computer to see if it's reacting, not the O2 sensor it self. His recap explanation is correct. The video needs some minor editing Great info. I was starting to worry about Duane .It's been a while since we've heard from him. Thanks.
some people dont know how to test them, that is why they may watch this. If you read some of the other posts you will see some people are trying to learn, which is good and I did not want them confused. I know already how to test and was just killing some time and looking to see what others do. So I guess you knew also that with the test light or by touching the battery, he was not testing the oxygen sensor at all!!
Very possible, however the sensor may be ok and the problem is you are stuck in open loop instead of closed loop. Check the loop status. If it is open loop, look for the reason the PCM is not managing fuel control. Possible things are open circuit on ECT sensor. Also, try forcing the Lambda sensor rich by adding fuel and lean by creating an air leak. See if it responds.
thanyou for that:) i also forgot to mention i have a code coming up 'catalysator breaking down process low' .i pulled a vac line to make it run lean, pre lambda about 0.1v and post lambda 0.35v. then connected so no lean condition pre is 01-0.9v and post 0.38-0.48v could the cat be blocked as im more confused as anything now lol but from what im seeing there working the post cat form what i understand measures the efficiency of the cat?as symptoms go ,pg isnt great and it being a 1.8 im not sure if its lacks a little power.
Авто/Мото
Your comments starting at 9:11 brought this whole seminar into clear light. In the first part you override the O2 sensor signal with an external signal, to see if the PCM reacts correctly. Then, in the second test you feed the vacuum intake with propane or room air, to see if the sensor reacts correctly. I'm gonna have to make myself a little adjustable propane source like you have there. Thanks again for your effort!
That blend of practical experience and science is cool. I always thought the idea of replacing an O2 sensor without testing it was, well, disappointing. Thanks for going through this, Duane.
The guy's a master tech. The video is not misleading at all. He showed how to test the computer's response and the O2 sensors output. If you watched the video all the way through at first you would have known that. It defies logic that people post comments on these videos when they don't know what they are talking about.
Bob Kodadek, yep, trolls posting stuff they dont know, (probably never even worked on a vehicle) and saying the master tech is wrong, well...Im speechless!
I am following your reports with great interest, and I am greatful and honored to be one of your students, thank you very much.
Very useful information and yes it does the sensor check and the computer test. Really good verbal explanation thankyou.
@AutoTechHector thats what he said. there were 2 tests in this video, one seeing if the pcm is responding correctly (wires to the battery) and the 2nd test with the vacuum leak/propane determined if the o2 sensor itself is bad or good
I agree he is taking the sensor out of the loop and creating a maximum value negative or positive as the pcm sees it, basically bypassing the o2 sensor.
Another very good lesson my friend. Great to see another video from you!
Mark Hicks
Wells Vehicle Electronics
yes, you are correct, he did show how to test the computers response, but when he was doing that he was saying that he was testing the 02 senor-which he was not. also again you are correct at the end of the video he did correct himself in saying that he was testing the computers response. I was just saying that through out most of the video he was saying he was testing the 02, which he was not! I just wanted to clarify that so that some others would not get confused
i wish i had you as my father :D i would have learned so much
This is a good test for old cars and a good teacher have used that test .now I would go to mode6 and check o2s
Good lesson helps auto techs understand better
Very informative for the new students beginner ❤
Awesome trick. This is good to know. Thank you
Brilliant and thank you so much.
Kind regards
Jay
@areskzc you don't need an expensive scanner, a 2 channel second hand scope (circa 50 to 100 sheckles from an online auction site) in good condition will do, all you are doing is tapping into the appropriate signal lines on a wiring harness.
Excellent lesson and tip! . I want to say that the person that states , he would just buy the new sensor cause they are cheap, did not grasp your lesson I think. May be he did , but let say he installs the new sensor and still the same problem ? Now he would have just spent money on a possible wire or computer problem..and there for is just a part changer. The object of the lesson is to test and see what the problem is before replacing parts...thanks
***** That is the object of the lesson . and I appreciate the lesson so that I can understand how to diagnose but I think Skilled Eddie , who just replaced the sensor was applying "cross discipline" problem solving
@realfixesrealfast Really impressive Duane u have it down to a science!! Excited to see u back.
The video was good in showing appropriate ECU responses to various conditions. The quantified varying voltage signal from the O2 sensor reflects the sensor. the comments of anonymic79 and cyborgdale are appropriate.
I like this channel alot Duane gets down to the meat and potatoes of auto repair. The beginning of his videos the editorical and graphics I quess that's what call it is super pro. Man it looks like TV.
Hurlburton only thing wrong with his channel is that he doesn't have enough of these good videos.
i really like how you explained things in this video, thank you so much for taking the time!!
It would be even better if he knew what he was talking about!
steve c that's easy to say.. but why don't you explain why you think he doesn't know what he's talking about?
Great teaching
Always enjoy your vids, very informative. Thanks.
Aren't you just testing the car computer's response to the oxygen sensor, and not the oxygen sensor itself? Isn't the oxygen sensor the device that is generating the voltage on the line that you are probing? I.e., the oxygen sensor is not "reading" the voltage that you are manipulating. If you want to test if the oxygen sensor is working properly, don't you have to test that the voltage being generated on the line is varying appropriately, based on the amount of oxygen in the exhaust? Am I totally off base here?
yusuihang : I think you are right. The test by connecting the O2 sensor signal wire to ground does not verify if the O2 sensor is working properly, but verifies that the ECU is repsonding properly to the O2 sensor input. So in fact it is a test to see if the signal wire of the oxygen sensor is not shorted or broken.
Exactly what I was thinking and scrolled down to see this comment.
He explained how fuel trim work inversely proportional to 02 sensor voltage= 02 sensor voltage near zero( 1mv)means lean condition , ECU see that raise positive fuel trim not over 10% to make 14.7 part of air to 1part of fuel ratio. In opposite, if 02 voltage go up near 1volt , fuel trim becoming negative taking fuel away due to rich condition.
That is very clever, the human resistor!
Excellent video a lot of info from a pro.
body resistance, neat trick.
thx for sharing
I do like all your videos, just wanted to point this out because it may confuse some people if they dont really understand what was going on here. I am not knocking you at all, just wanted to clarify this, and say thanks for all your good and informative videos.
Good instructional and test video.
If you're unlucky and can't get the right resistance with your body, go to your local electronics store and buy a 12k and 1k resistor and a few alligator clip test leads. Connect them in series between battery plus and negative (12k to +, 1k to ground). At the junction between them you will now have about 1 volt, depending on your battery/alternator state. Measure with a multimeter to be certain.
Always good stuff , I really like your video ,pls keep it up
perfect , good explanation. love it
I don't see how forcing the o2 sensor wire to gnd or 1v proves the o2 sensor is good or not. I think that is testing the PCM's response to the 2 voltages. Even if we did this test without a o2 sensor in circuit, the wave forms would behave the same way. Please comment.
Terry Gee his scope showed the sensor working properly but maybe the vid should have been titled more accurately.
Wayne is a Instructor at a local College. He's an expert at Automotive Repairs. He's one of the best. Some people are idiots.
Good video! Now if I can only check out my short term fuel trim =) Nice tool.
I wish I had had someone like you to apprentice under before I became a licensed mechanic, wouldnt grounding/forcing to 1 volt the signal wire only test the integrity of the wiring harness and pcm's ability to respond, instead of the actual O2?
I would like to see a module for wideband O2's in the future.
Justin
@AutoTechHector agreed. I believe that's what he meant to say or was the test's purpose
Forcing the sensor wire to ground or to +1 volts only shows that the PCM is properly responding to the changes--not that the O2 sensor is good. Creating a rich condition with propane (and then a lean condition with a vacuum leak) while observing the sensor will show whether or not it is good. You must also test to see if it is sluggish. At 2500 rpms it should cycle 2-3 times per second for a single-port system and 5-7 times per second for a multi-port system. Engine must be at operating temp.
My Buick LaCrosse 2010 cxs 3.6 direct injection. Downstream O2 sensors are both running at 0.75 I know it goes through fuel 13 mpg
What good is it to add sensors to vehicles if now they are another thing you should first doubt and add to the trouble shoot? I'm no Mechanic but always here about people sending there cars in for a check engine light, sensors going bad, and costing folks $65 hr + parts + tax. Good for your Mechanic!
Nice logical troubleshoot video mister.
I didnt understood how you connected your wires to sensor ones. You havent disconected it, just added extra wires to it?
this is not testing the o2 sensor !! THIS IS TESTING THE PCMs RESPONSE TO THE O2 VOLTAGE !!! the o2 sensor itself could still be broken
Very Very Nice.. Thanks
Awesome and no B.S ! thanks.
Never thought about peggin an O2 sensor rich by holdin a jumper wire in one hand and the B+ terminal in the other.
How did you figure your body is 11 volts resistance?
I was dead when he did that
I have had O2 sensors crash under load. Customer brings on a 93 toy truck failing smog. In bay the O2 was fine and made me test all sorts of things. Testing it on the dyno showed that the O2 was crashing lean. I had an 82 Mazda pu trowing a code 17. O2 went .450V AFTER 8 miles of freeway driving. CARB adopted testing with propane to test min/max and rise time which should be 100ms or less (most good O2 sensors will be aprox 50ms).
Jim
Eve's Automotive
evesautomotivedotcom
Yours videos are awsome sir corecact me i am wrong when we convert a vihcles in CNG or we cut off fuel and runs car on CNG OR LPG i think the O2 sensor not much important in that case in easy way we can run a car in cng without o2 sensor
you can do this with a GMM and code reader with live data. about $200 in equipment
@vtecboy9 You should be able to, I have used the ELM on my diesel 54 plate (2004) UK citroen C5, and the free software shows live data, fault data and sensor data. For all it costs, give it a try.
I have a 98 dodge ram 1500 with 5.2. Pulls a po171 code lean bank one slow response. I have replaced every sensor , vacuum leaks,idle control valve, catalytic converter, gasket under throttle body. Mas sensor. Can undo battery put back on truck runs great for fifty miles engine light comes on idles up and down, gets 5 mpg and reads lean bank one code. There's nothing else to replace that I know of. Help. Short term fuel reads 32.5 long term 0.0.
thinking that using the test light or touching the battery is testing the 02 sensor. also please see the above response from anonymic79
Interesting ,good post
Very informative, thanks for the info.
thank you so much for the video. i have a question. is that torch with the propane tank home made? if not do you think its safe to cut a regular torch head off, put some tubeing like in the video and make is somewhat like yours
good stuff I always learn on here
GOD BLESS YOU SIR...THANK YOU !!
hey duane is there another way to analyzing the fuel reacting to the o2 sensor without a scanner?
Everytime I see one of these videos I feel like "Let's do it" then I realize I don't have that expensive scanner... (poker face)
Here what you do. You give the customer two options. Option one toss an o2 in which will 99% of the time will fix the problem. And option two what your doing which will cost $109 an hour. No real shop is going to get that labor inventive unless there's a second visit for the same problem.
thank you very much.
can u also perform this task with a snap on modis or solus scanner and view the data on the monitor during testing this procedure.
has to respond in a certain amount of time as well, from .1 volt to .9 volt in 100 ms
My problem with my BMW e90 320i 2009, 4 cylinder engine with 2 banks
cylinder 1 & 4 is bank 1, 2 & 3 is bank 2. i am suffering from high mileage that is around 12 L/100km in the city and 8.5 L/100km highway (the standard is 9.3 L/100km in the city and 5.7 L/100km highway).I don't have any codes in the OBD II check tool, but using torque app i am getting a strange value of (fuel trim bank 1 / 2) that is +99.2% and this value is constant on idle and on high speed as well .the other fuel trim bank value (fuel trim bank 2 /2) is fluctuating normally from + to - as per the load and drive conditions.
I will appreciate any help ideas.
man ...this is RIDICULOUS ... JUST TEST the O2 for switching below 0.2 and above 0.8
bad o2 sensors are in between that or are stuck mostly rich.
if you have a leaky injector it will smell like it.
if you have an electrical issue it will smell like it.
if you have a plugged injector it will misfire clean.
never touch any battery terminals with any wires ... YOU'LL BURN the ECU ...
One more thing: In my OPINION
people are obsessed with O2 sensors and unnecessarily replace them.
Mr. Duane,
Do you think sometime in the near future we will see, 1 A/F ratio sensor per cylinder? for example, 6 cylinder engine with 6 A/F ratio sensors mounted on each exhaust runner? Over the years we have seen 1 injector per cylinder then 1 coil per cylinder (COP). Do you think this would make sense? could engines be more efficient this way? of course I suppose the pre-and post cat sensors would still be intact. anyway this is just an idea, wanted to throw it out there thanks?
My car, has 2 o2 sensors, i took off tha catalitic so, should they be working the same?
Your are very good mechanic . Good explanation and understanding . I will subscribe and follow
i have a solus ultra, i can still do that test with that scanner right, and also how do i know wich cable can i tap into from the oxygen sensor,
duane have you ever come across a repeat P0133 on a 2003 hyundai elantra gt ? my last option is to test the O2 grounds .
Welcome back Duane!
Great video. Makes sense
Hello Real fixes,
I have a lean code p0171 check engine light is always on, the cr run
fine and idles fine. air/fuel sensor fluctuates between 600 to 800 down
to 200. the fuel trim long term is 15 + and the shorterm fuel is -14.
Check for vacuum leak engine cold sprayed water all over intake manifold
, vacuum hoses , exhaust manifold, its normal. The air/fuel sensor
drop to zero volts when I pulled the vacuum hose from manifold . Does a
zero volt reading point to a faulty o2 sensor , its a 4 wire , on Toyota
corolla 2000 4 cyl CE 1.8l.
Now today I will check spark plugs and injectors, its repeated ticking
sound points to both injectors and spark. spark advance on the obd tool
reads 15 with a G letter . What does it mean?
I have not back probe the o2 sensor because I can not find its o2
specifications on voltage drop and I don't know if its a wide band or a
narrow band sensor.
I cant find the fuel regulator in the engine. And I need to inspect all
the vacuum hoses too. Its like being a medical doctor, I only have 150
hours of training with certificate from the 70s and learning all this
analysis with fancy digital scanners can be very expensive for just a
do-it yourself-er.
can I use a volt meter with an amp probe together on a o2 sensor signal
wire, instead of back probing?
Can I use the wave screen on the less expensive OBD scanner, to see wave
forms along with amp probe and wire clip , How do I set this up?
my o2 sensor is bouncing up and down all over the place does it mean it's bad ..the second sensor is more stable at almost a steady number
David it sounds like your sensors are working as they should .
nice video , how about the down stream 02 behind the CAT . Should it be switching as often as the up stream 02 . just did a reading on my scan tool and the down stream 02 is almost a straight line with no indication of switching .car is burning a lot of fuel . 2001 Olds Bravada 4.3.
keving52002 the post 02 sensor should be steady while pre should bounce all over
awesome video
Can a map engine with 02 bias circuits be tested the same way?
Sears - actron cp9580 plus scan tool 179.00, i am certain there are other brnad scan tools with live data reading. They do a good job no need for the thousand dollar scopes the technicians need.
false air from cylinder with plugged injector may cause false 02 reading and other sensors to misfire rich due to additional unneeded fuel...
real teacher realmechanic
so weather it be sensor 1 or sensor 2 on either ban each sensor displays ltft and stft? I was under the impression sensor 1 is only for stft and sensor 2 is ltft.
Jesse Ruiz sensor one uses both trims
Duane , is your tool for propane enrichment still avail? thanks rick
Is it really worth testing 02 sensors? I got 2 Denso upstream sensors for my truck for a total of $50. I just replace them and be done with it. If they are original and the car has a lot of miles just change them. To me the part is too inexpensive to waste time diagnosing. Now stuff like a MAF sensor that can cost up to $300 that's something you take time to diagnose.
+SkilledEddie This is really and instructional video which shows how to test the sensors. In some cars it's very difficult to get to the sensors or the parts is really expensive in which case you really need to make sure you actually need the part before replacing it.
+SkilledEddie in Europe a o2 sensor can be $300-350 for a mazda 3 while in the US a guy bought one for
$25
Even here in the states my Rav4 up and downstream o2's are over $100 and there are four! Definitely worth testing!
Great video! I needed to know what the individuals wires did on my 4 wire o2's.
yes, i seem that he just added an extra wire to the sensor signal wire and ground it, the other test, he creates a very small millivolt by hand resitance , he just touched one end of the same extra wire and with other hand touch batter positvie post
That voltage must be doing something to his body
dcomputers Not really. It's not volts that can cause damage. It's the amperage. He's just acting as a resistor with low voltage and amperage.
It's actually both. Voltage is the pressure, but I agree. This won't hurt you.
thank u sir, u are a good teacher, i have a grand am gt, my oxygen sensor bank1 is broken, i cant take it out , pleae tell me how to remover and installing oxygen sensor on grand am gt please, thank u sir
Hi, I need help. I have a honda accord 02 which I put a new engine. the oxygen sensor upstream was bad but I have replaced 3 Times already and still have the engine light on. what can I do.
The oxygen sensor is just that, it senses and reports what it finds. It is very very unusual that 3 of them would be bad. More likely, they are actually reporting correctly and setting a code. You would really need to test the sensor instead of just assuming it's bad. Have a tech test it. If he knows what he is doing he should be able to force the sensor to read both rich and lean and watch the scanner data. If the do indeed respond correctly when forced rich or lean then the sensor itself is good. You then would need to see why your engine is running so rich and/or lean. Hope this helps.
You are totally wrong. In LPG conversion(modern one) ECU is still regulating mixture using all sensors as normal. LPG computer is just "translating" fuel injector opening times to lpg injectors opening times.
Duane, whose wire tap are you do you use ? thanks rick
let me see if i understand
by you giving that wire 0 and 1 volts you are not forcing the sensor right? you only mimic the sensor signal ,but sensor still doing his job.
I tought the 02 sensor produce "output" 0to1 volt signal not react to it ,computer reacts to it.
o2 sensors read levels of o2 and report to the computer as 0 to 1 volt,
sounds like 02 sensors read fuel,
i tought 02 sensors were there to monitor the oxygen,
rich o2 = no fuel,misfire or stuck injector
Can u show us how to do this with a digital voltmeter
you should have a wiring diagram so you know which wire is the signal wire going to the computer
If you are testing a wide band sensor will the results be different than a narrow band??
Yes, they are completely different
Can you explain the differences if you can on a video
@DiyMech
Hello,
Can i use the cheap ebay ELM327 to do this test???
Good video!
nice video
engine light on ho jati hai aur catlyst converter kharab hona shuru ho jata hai. pata kerne k liye Code reader lagana parta hai
@Cummscott Read the video description.. it says the same thing as he says in the video. He's wrong isn't he.??
I don't think Duane properly explained what he was testing IN THE BEGINNING. He says to ground the O2 sensor output lead to ground, and then to the battery, to test the O2 sensor. That;s not correct. Doing that tests the computer to see if it's reacting, not the O2 sensor it self. His recap explanation is correct. The video needs some minor editing
Great info. I was starting to worry about Duane .It's been a while since we've heard from him. Thanks.
some people dont know how to test them, that is why they may watch this. If you read some of the other posts you will see some people are trying to learn, which is good and I did not want them confused. I know already how to test and was just killing some time and looking to see what others do. So I guess you knew also that with the test light or by touching the battery, he was not testing the oxygen sensor at all!!
I have a Bmw e46 with the rear lambda stuck at 0.45v I presume that means there is a issue with the lambda sensor ?
Very possible, however the sensor may be ok and the problem is you are stuck in open loop instead of closed loop. Check the loop status. If it is open loop, look for the reason the PCM is not managing fuel control. Possible things are open circuit on ECT sensor. Also, try forcing the Lambda sensor rich by adding fuel and lean by creating an air leak. See if it responds.
thanyou for that:) i also forgot to mention i have a code coming up 'catalysator breaking down process low' .i pulled a vac line to make it run lean, pre lambda about 0.1v and post lambda 0.35v. then connected so no lean condition pre is 01-0.9v and post 0.38-0.48v could the cat be blocked as im more confused as anything now lol but from what im seeing there working the post cat form what i understand measures the efficiency of the cat?as symptoms go ,pg isnt great and it being a 1.8 im not sure if its lacks a little power.
I was taught this in class many many years ago. Old school.
Jim
Eve's Automotive
evesautomotivedotcom