Logical scientific troubleshooting always wins. When logical diagnostics don't work look to find out what you have missed becasue it's science and it always works when applied correctly.
Thanks sir, I am from this part of the world, 🇳🇬 I am in interested in joining your quantum mechanics, Your serious lectures on FUEL trim helped me level up in troubleshooting engine issues, and I have used it to troubleshoot my vw and ford contour 98 2.5L duratec v6..👍🏾
I have both banks running lean warmed up or not. Some times worse then others. Both banks go to 15 to 25 percent long term and when you press the gas it gets better for a second and goes back to right about where it was. O2 sensors are fine and only a p0171 and occasionally a p0300. 2005 chevy silverado 5.3l
hey matt , you are right about vehicle engineers the toyota's engineers they need not just a punch on throat they don't put a schrader valves in many toyota vehicles for that you have to buy a (sst) special service tool to measure the fuel pressure :( . i take a fuel line from the junkyard and some 1/4" fittings and hoses and now i have my own sst .
Ah great question and thanks for reminding me. I have meant to do a video doing an experiment testing effect of fuel injector cleaner on valve deposits but I never got around to it. The challenge is having a scientific control- it’s easier to show it can reduce existing deposits but to show it prevents them would require two identical engines driven identically- one with treatment and one without.
@@SchrodingersBox that would be awesome, however I understand the intrinsic difficulty of doing such a study. Still, I regularly use fuel system cleaner, albeit knowing that it could be useless. However I know for a fact that my second hand car has been badly mistreated by the previous owner and using the product would, at worst, be a reasonable waste of money. However, if a P030x DTC should show up, fuel injector cleaner wouldn't be the first thing I'd throw into my tank thinking it would solve it. Oh no. Have a great day Matt and, as always, thanks for replying!
@@SchrodingersBox c'mon Matt..we have even spoken when I tracked you down to Danaher years ago Faithfully watched and enjoyed every video for prolly 11 yesar. 🙂
Excellent vids! From N/W Scotland. You guys are always on about using propane to force a rich condition. In the garage we already have OxyAcetylene. Could putting just Acetylene in the intake work just as well?
Love your channel! Alot to learn. You are the best on the internet by the way. What about a loose wire connection on the plug on the fuel injector being vibrated from the engine when running cause a intermittent condition. And could a coil on fuel injector over heat from input voltage causing issue. And what about mechanical issues with fuel injector of possible intermittent issues.
Awesome video series.... Off topic question....I feel a slight shake at idle that is intermittent but definitely there enough to bother me. I am starting to rule out engine performance after watching fuel trims for the last 300 start ups lol. I am learning so I am taking my time with this. In your opinion can a bad harmonic balancer cause a shake at idle that isn't too violent when it first starts going bad? I am just trying to rule out mounts and I just can't see how mounts would show up like this with the car in park and mounts I thought were more a vibration than a shake....I do see dryrotting/cracking of the rubber on the balancer....also when I pay very close attention when starting the engine and before it fires up I can feel this same shake as the engine is turning over.... I know this is hard for you to say without being in front of the vehicle but just curious if a bad balancer or a balancer that is just in the very beginning stages of going bad could cause these shakes at idle that is felt worse in park/neutral....going in gear seems to hide this shake. Thanx for all the videos you do. You help so many of us out. It really is incredible with TH-cam how you can affect so many lives. 250k subs but I bet you are even influencing many more than that! Again...thank you for everything you do. You really should know that we really do learn so much from you.
I had actually suspected a bad balancer when I was setting timing on a 92 camaro with an L03 305 TBI. I was concerned that the timing was off despite having set it to 0 degrees BTDC with the EST connector disconnected and I didn't want to make the assumption that the timing mark was actually correct. One theory was that, since the harmonic balancer is two pieces with rubber separating them, that rubber can go bad and the outer piece can slip. This would cause not only the timing mark to become inaccurate but also the balance would be off. So there's a test you can do. Engine off, pull the plug on the #1 cylinder, rotate the crank pulley to a few degrees BTDC on the timing mark, and what I did is I put my phone camera down next to the spark plug hole so I could see the piston moving, then I turned the engine to 0 degrees on the timing mark, stopped, made note of where i was to the camera, then continued past it. If the piston moves upwards before you hit 0 on the harmonic balancer and then downwards after you hit 0, the balancer has not slipped. If it keeps moving in the same direction or you see it change directions at any point that is not at 0 degrees on the balancer, the balancer has slipped and you can be absolutely sure that you need a new one. Turns out in my case it had not slipped and I was just making things up - the issue is something else entirely. And by the way, there was a point where someone had swapped plugs #1 and #2 (these are next to each other on the same bank in this car) causing a misfire on both cylinders and that made the car shake a lot. Since you said fuel trims seemed good that's probably not the problem.
@@polymetric2614 thank you for the detailed response. I formed a lot of rust on my balancer. Sounds crazy but I wonder if the extra weight of the rust buildup could cause it to be out of balance.
um I think it would be a good idea hear to add to the balance test. that putting it on a charger is always a good idea. false readings from a under charged or weak battery is possible and could lead to a bad diagnosis. I think your channel is leaning towards entry level technicians mid level wich I think is totally awesome but this was learned the hard way. its amazing what you will remember from a you tube teacher
Justin that's a great idea. I can see how this is possible especially considering you are in KOEO for the duration of the test- the last injectors done might be performed under weaker battery than the first ones.
How to find out the expected range for mass airflow sensor if the manufacturer does not provide the figures? I have 1999 Golf IV with 2.0 petrol engine, I have rich fuel trim at 22% on load, there are no driveability issues. I tried to clean MAF as instructed, but the problem still persists, I thought to test the output values and find if they are reasonable. On idle they are 7.5 celsius, 3.5g/s airflow, but under load (3k rpm) it is 55g/s. I tried this formula Volumetric Efficiency Calculator | OTC Tools. It says that the output of this formula should be 75-90%, but putting my data it is about 60%. Does it mean that MAF is bad?
You proved that the filter isn't the cause of the pressure drop in a static situation. I agree that the pump is bad at this point, but a clogged filter could be responsible for the failure. A flow restriction at the filter would cause the pump to run at a higher than designed pressure/duty cycle which would shorten its life.
Dennis Rindlisbach That's OK. Fuel filter restriction is ruled out though, because I tested pressure from the pressure line before the fuel filter and got exactly the same reading. This eliminates any restriction in the entire fuel line.
i consider plugs and wires to be normal maintenance items that should be replaced anyways if you never have done it on the car. it may or might not fix the problem but if you never have done it to the car there is a good chance it needs it anyways. if i had a misfire code i would run the car at night to see if their is any arching
andrew donohue my wife's 1996 bonneville was throwing a P171 mis-fire code and yes i did replace the plugs and wires and yes it did fix the problem but we have driven the car 30K miles and never did plugs and wires to the car. if that had not fixed the problem i would have continued with some reasoning and logic. when i replaced the plugs and wires i used reason and logic to come to the conclusion that the car was stumbling really bad, was throwing a code and i never did plugs and wires to it so it was overdue anyways
Reason and logic requires that plugs and wires would be the ONLY possibility. How were other possibilities of all the other parts that also weren't changed out ruled out? How did you logically rule out fuel pump for example?
if i had done plugs and wires which had allot of miles on them anyways and i still had a problem of, course i would have continued on testing. it was a P0301 meaning only one cylinder was affected so its unlikely that would be the fuel pump as that would effect ALL 6 cylinders and would have been a P0300 generic misfire code. i would hook up a scantool. i would look at long and short term fuel trim. being that only once cylinder was effected it would probably be plug, wire, or injector. you could also hook up a niod light to make sure that injector is in fact getting its pulse. also if i moved the wires around the code would go away and the car would run better. other things you could do to check for a bad wire include spraying them with water, watching the car run in the dark. it will light up light a Christmas tree if the wires are bad, in fact i think i did that too
+Schrodingers Box i'm learning english and mechanic at the same time , thanks men from south america , we need more people like you in my country ,!!!!
Schrodingers Box of course we know that plugs and wires aren't a cure all for every problem, that's just un-reasonable and illogical. in that case i could hear snapping noise that was coming from the ignition wires, it was a pretty good indicator. one of my other vehicles was recently suffering from a mis-fire. that car also needed plugs and wires, it would act much worse when the weather was damp or wet. again my suspensions were correct plugs and wires. aged ignition wires are susceptible to moisture and engine load. if you have bad wires often times the symptoms will get worse when the wires get damp. they car also ran worse under a load, usually that's ignition related. had the $30 plugs and wires not fixed the problem, my next step would be a fuel system pressure test. when i buy a car relatively cheap and it has allot of miles on it, i will assume that eventually it will need wires. the car in question is a 2000 GTP and has 162K on it. the wires were the original ( i suspect) ac delco wires that were numbered for the cylinders. 162K i think they had a good run
Always love a good Kilmer channel jab. I get annoyed whenever I'm watching quality diagnostic videos and his trash gets recommended for me to watch. I always have to stop myself from clicking on the video just to comment.
@@charlesgould8436 I'm not convinced he was ever a mechanic. His videos are mostly opinion based and sometimes flat out wrong. It's always a good idea to avoid a video with a title on how to fix something. The good videos are titled, how to diagnose something.
1992 Voyager 3.3 Liter V6. Starts OK, Will Idle for about a minute until stalls as the IAC opens and the motor can not respond appropriately. No distinct miss at idle , just struggles to keep idling, notable heavy modulation of IAC trying to maintain idle, application of throttle brings about severe misses /missing, pops and sputters, intake back fire indicative of over lean condition at just barely above idle, very hard to gain any engine speed/ rpm, IF the engine does manage to get above 2000 to 2500 RPM ( estimated because there is no tach) THEN engine instantly smooths out and runs normally /revs aggressively in high contrast to horrible stumble in region of just above idle to 2000 RPM. (I admit that I already did the part swapping gambler approach that you do not like, with no remedy on my part) Already changed TPS (new) no remedy took it back (Thanks AutoZone) , Map Sensor (used from Wrecking yard) and ECM ( used from wrecking yard). No change noted as mentioned parts were replaced. Checked for vacuum leaks in area of Throttle body with unlit propane torch, no effect noted. Contemplated EGR problem. Checked engine for EGR. Apparently this engine has NO EGR system. At this point wondering about any possible IAC issues / suspect of Junk Yard MAP. I tried some stuff, with no success. Seeking outside input at this point before proceeding any further. Can a faulty fuel pressure regulator cause that kind/ degree of problem? I am doubting it. Can a faulty O2 sensor cause that degree of problem? I am doubting it. Crank Evac check valve ? I am doubting it. Anything else ? Thanks in advance. Up date: Watched the video on fuel pressure regulators on this youtube channel. I am doubting that is the problem. FPR are to drop fuel pressure, so if they fail there is no pressure drop resulting in a rich condition. It appears that I am dealing with a lean out condition. The My next planned move is to test the MAP sensor with a multi meter.
I hooked up a Multi Meter to the wiring leads for the MAP sensor. It showed 5 volts supplied to the sensor. 4 volts at signal wire with engine not running but key on. Idling 1.5 volts, 2.5 volts shown on throttle blips. I did not take the engine into the RPM range where it smooths out and runs well, so no Signal Volt reading there. Maybe I should have. Problem still exists, as the MAP sensor appears to be functional as tested.
So I will watch your video on fuel trim, and try to get more savvy on the subject. I am trying to take the initiative. thanks for your attention thus far. You have been infinitely more helpful than the Chrysler Minivan Fans forum. I really want to solve this problem. It seems to me that I am working with a lean out condition being the problem as indicated by the intake popping opposed to an overly rich condition which would make heavy dark smoke with heavy gasoline smell and more even /general sluggishness.
The O2 sensors get dropped out of the loop when you go WOT as the PCM goes into enrichment mode. Whether or not the O2 sensor still report the correct value I'm not sure
I have Mercedes C180 model 1999 I have error P0170 my STFT is changing normal when I press the accelerator paddle from - to + but the LTFT is fixe on 0.8%please can you explain why and what will be the error
I am glad you realized that it was a joke!!! I LOVE your videos!!!! Keep up the good work. It truly reminds me of Arthur C, Clarke when he said: "Any sufficiently advanced technology is indistinguishable from magic" I feel most people consider modern auto mechanics as . . . "MAGIC". CHEERS!!! Uncle Duke
the bruthus on. In my case, I hope right now, is the damn engine either has a stuck open thermostat or NO thermostat. The engine is running at 130 F degrees, per what my tool says, and the temp gauge on the dash is barely reading off of low. The cabin air is not all that hot either. I cant fix my lean condition until that is correct, and maybe it will go away once proper temp is reached. I wish this guy was my neighbor. oh I failed because on another video I did say fuel injector cleaner. I only say it because I get better MPG if I put that stuff in once a year and I've cleaned many an IAC valve from garbage in fuels. Not looking for an argument, I know fuel injector cleaner isn't a fix all and should not be used as such.
Omg yes on the Schrader value. My friends 2005 kia sportage 2.7L needs a adaptor tool that cost $100. Fuk you kia! I rather throw in a new fuel pump assembly. Hear me out lol. It has the fuel pressure regulator and filter built into the assembly. It has never been changed and has 90k miles. I rather waste my money on that instead of a tool ill never use again lol.
Help plz. 2005 Corolla with p0171. So far have changed the maf with Toyota oem part. Replaced both o2 sensors with denso. Changed intake gasket. Changed catalytic converter due to a leak. Fuel pressure reads at 49 psi. Removed and cleaned fuel injectors. No vacuum leak. Car running very rough at idle. At idle, short term fuel at 0 and long at 25. At 2000 rpm, short at -4 and long jumps to 40. Any ideas plz.
What was the data you got that indicated you needed to change the MAF? What was voltage and frequency? What was the LTFT and STFT curves idle vs load? You need to start with that data because you clearly overlooked something causing false diagnosis.
How do you deal with someone who brings you a poor running car, that hasn't had service in a long time. Would you advise a service first before diagnoses or just go straight into looking for a specific problem?
Hahahaha not sure why you would do that but I can assure you than unless both banks were perfectly 100% tuned the car would run terrible. The reason being is think about it- one bank needs just a very slight fuel trim so the PCM adjusts fuel trim on that bank. BUT the OTHER O2 sensor sees the adjustment. So now THAT bank gets an adjustment which is seen by the first O2 sensor but it isn’t the adjustment called for which in turn calls for another adjustment which is again seen in the wrong bank and the procedure would repeat until both banks had their trims maxed out in opposite directions.
Hahahaha. I have never even once bought a can of that ish. or is it on a bottle. I don’t even know lol. SEA FOAM= Someone Else As Foolish Offered Advice Moronically.
P0171. And misfire codes Ltft at %40 Stft around % 0. I've changed ignition coils and maf I notice o2sensor bank 1 s1 is at 3.1v idle and bank 1 s2 is at .07v idle. Is it my oxygen sensor? I press gas and b1s1 moves normally but b1s2 graph is straight Most of the time Toyota Corolla 2007
@@SchrodingersBox I replaced the coils and maf sensor and thought it would help as they never been replaced. It improved performance a little bit but I'm still getting p0171 and misfires. I notice that my b1s2 voltage doesn't move at as quickly as b1s1 and looks very blocky on the graph
@@jaggerc.2017 Well thats a guess- not data. I need to see data such as induction metrics and the fuel trim data to make any judgements. Without the foundation of basic-level data you can't even get a direction on what the issue could be. I need a basic starting point.
I am sorry but if you are going to be fully methodical and scientific, the 2nd guy is completely wrong. The only thing he verified that the ignition cable had no continuity, so he knew the cable was faulty. BUT he did NOT check anything else. For all we know, more parts could have been wrong. Your second guy is "Scotty Kilmer" in desguise! Actually, I personally have no problem with him and appreciate his videos for the complete non-sense approach to fixing ones *own* car in less than 270 seconds or less :-) Heck, his clutch replacement video was the shortest video ever shown on youtube for any clutch replacement :-) If you want to take shots at others, then show the stuff where not only you diagnosis the bad part, you also rule out all the good parts. I hope when you work on the car, you are the 1st guy and NOT the 2nd one!
But the second guy did rule out that the were no other causes. When he replaced the faulty wire and ther was again spark, it confirms there MUST also be coil control, coil spark, plug spark, fuel, and compression
OK, so he replaced faulty wire and then car ran OK, so obviously that was the only problem in *this particular* case. What if he had to order the $300 wire and had a week long wait on it? He needed to make sure that was the only problem before ordering the parts. Otherwise, how is he different from the Kilmer guy? No, he is a part swapper but at least least he is swapping a bad part after making sure the part was bad. Once again, I expect a logical person to make sure not only is he replacing bad part, he is making sure he has verified that there are no other bad parts before he replaces a known bad part. Yes, replacing the wire here was trivial and cheap but we are talking about principle of diagnosis here not how to get the car out of shop and make a quick repair. I would expect a competent person to verify bad part and also make sure everything else is working correctly before ordering the replacement. If the wire AND spark plug were both bad, he would have replaced the wire and then swapped the spark plug etc. Nothing wrong with that bad part swapping approach but let us call it what it is.
Yes I see your point- the whole idea was just to make a point with the moral of the story and not focus on the actual case study example. I should have pointed out the misfire example was strictly a no-spark one I guess lol.
Hello I have a problem with my 98 bonneville 171 code and multiple misfire code I have changed all spark plugs and wires and coil packs I checked the fuel trim short term is 25 at idle goes to 0 when 60 percent throttle long term is 16 percent I checked fuel pressure 48 psi fuel pressure regulator is working I have checked for vacuum leaks at intakes and all vacuum hoses no leaks detected I can not figure this out can you please help ?
hello I got a p0171 on a V6 engine bank one could a exhaust leak between the two O2 cause this problem that happen after cleaning the catalytic converter I was getting p0421 and p0431 that is fixed for now.
Yes by cleaning my catalytic converter got rid of the codes p0431/p0421 but after putting the catalytic converter back now I got code p0171 on bank 1 fuel trims are short trim at 13% and long at - 12 % there is a exhaust flange at the end of the catalytic converter between the two o2 sensors.
@@SchrodingersBox I have a mystery po171 131. I've replaced entire exhaust system manifold back. No vac leaks from. My test. Fuel pressure is good. New 02s good clean MAF new temp sensor. Only thing I haven't checked and can't is injectors. I have driveability issues. My fuel trims look good. 2 things I can't check ans not sure about is the Injectors and pcm. It's a chevy 6.0 vortec. Simple engine. But I'm lost. It's been to a Few shops and they just throw there hands up and say just run it it runs fine. Smh. It runs pretty good. But do have driveability issue. Just seems to struggle. Merry Christmas man
i am looking very good mechanic like you in arizona,please let me know if you have friend (mechanic) he do great job like you. i have same problem with my 2007 escalade esv. Thank you
Either way... if cleaning an O2 sensor worked- which it doesn't- the fact you would need to clean it indicates there is a A/F ratio condition requiring correction anyway. In other words- cleaning an O2 sensor will not fix the cause of a problem.
love your channel, very informative but lay off scotty im sure he forgot more than you can do with your computer and dry erase board. Ill keep watching for now. A man i once worked for told me anyone can be a mechanic as long as you have a computer. the key words are" once worked for"
I highly doubt scotty forgot more than I know since he wouldn't know how to diagnose a P0171 to begin with- he'd just change the O2 sensor. If he forgets how to that he's in big trouble since parts changing is all he does.
process of elimination. Saves money and educates.
Well done in teaching how to better diagnose a problem. I've seen many videos telling you the issue when it is not.
Good tutorial
Thank you very much! I agree. Too many videos focus oon parts changing on a guess.
Logical scientific troubleshooting always wins. When logical diagnostics don't work look to find out what you have missed becasue it's science and it always works when applied correctly.
Absolutely correct. If the “science” didn’t work it’s because a variable was overlooked.
A big thanks-- very clear and informative! Great for us DIYers keeping older cars!
Thanks sir, I am from this part of the world, 🇳🇬 I am in interested in joining your quantum mechanics, Your serious lectures on FUEL trim helped me level up in troubleshooting engine issues, and I have used it to troubleshoot my vw and ford contour 98 2.5L duratec v6..👍🏾
Most welcome. The quantum mekanix channel is at www.schrodingersboxqm.com
my personal enemies:
scotty kilmer viewers
engineers who make cars without schrader valves
Roger that!!! I wonder if they are the same people lol
@@SchrodingersBox Have you found an engineer that designs fuel systems?
Very advanced channel! love it, keep making more videos!
I have both banks running lean warmed up or not. Some times worse then others. Both banks go to 15 to 25 percent long term and when you press the gas it gets better for a second and goes back to right about where it was. O2 sensors are fine and only a p0171 and occasionally a p0300. 2005 chevy silverado 5.3l
It’s always easier to diagnose when both are lean. Only a few variables.
The GM’s of this era (4.3 as well) seem plagued with various vacuum leaks
hey matt ,
you are right about vehicle engineers the toyota's engineers they need not just a punch on throat they don't put a schrader valves in many toyota vehicles for that you have to buy a (sst) special service tool to measure the fuel pressure :( .
i take a fuel line from the junkyard and some 1/4" fittings and hoses and now i have my own sst .
Oh man, your dry sarcasm always gets me... it's so refreshing after a day of hard work
Ah great question and thanks for reminding me. I have meant to do a video doing an experiment testing effect of fuel injector cleaner on valve deposits but I never got around to it. The challenge is having a scientific control- it’s easier to show it can reduce existing deposits but to show it prevents them would require two identical engines driven identically- one with treatment and one without.
@@SchrodingersBox that would be awesome, however I understand the intrinsic difficulty of doing such a study. Still, I regularly use fuel system cleaner, albeit knowing that it could be useless. However I know for a fact that my second hand car has been badly mistreated by the previous owner and using the product would, at worst, be a reasonable waste of money.
However, if a P030x DTC should show up, fuel injector cleaner wouldn't be the first thing I'd throw into my tank thinking it would solve it. Oh no. Have a great day Matt and, as always, thanks for replying!
Thanks for sharing your great experiences.
Bernie !! Ms Vikki and the Cat are missing here. MEOOOOOW. 😀
Goddammit who is this guy lol
@@SchrodingersBox c'mon Matt..we have even spoken when I tracked you down to Danaher years ago
Faithfully watched and enjoyed every video for prolly 11 yesar. 🙂
Real name?
Embrer. . can not you see that on Google ??
Nope. Seems I know you personally. You sure as hell seem to know me personally.
Ya know man, your channel is fantastic in general, but these interactive ones are really engaging and awesome
Thanks, they are my favorites too- its where you can really learn the fundamentals. Happy Thanksgiving man!
Excellent vids! From N/W Scotland.
You guys are always on about using propane to force a rich condition. In the garage we already have OxyAcetylene. Could putting just Acetylene in the intake work just as well?
Yes it would - have done it several times in fact
Love your channel! Alot to learn. You are the best on the internet by the way. What about a loose wire connection on the plug on the fuel injector being vibrated from the engine when running cause a intermittent condition. And could a coil on fuel injector over heat from input voltage causing issue. And what about mechanical issues with fuel injector of possible intermittent issues.
Awesome video series....
Off topic question....I feel a slight shake at idle that is intermittent but definitely there enough to bother me. I am starting to rule out engine performance after watching fuel trims for the last 300 start ups lol. I am learning so I am taking my time with this.
In your opinion can a bad harmonic balancer cause a shake at idle that isn't too violent when it first starts going bad? I am just trying to rule out mounts and I just can't see how mounts would show up like this with the car in park and mounts I thought were more a vibration than a shake....I do see dryrotting/cracking of the rubber on the balancer....also when I pay very close attention when starting the engine and before it fires up I can feel this same shake as the engine is turning over....
I know this is hard for you to say without being in front of the vehicle but just curious if a bad balancer or a balancer that is just in the very beginning stages of going bad could cause these shakes at idle that is felt worse in park/neutral....going in gear seems to hide this shake.
Thanx for all the videos you do. You help so many of us out. It really is incredible with TH-cam how you can affect so many lives. 250k subs but I bet you are even influencing many more than that! Again...thank you for everything you do. You really should know that we really do learn so much from you.
I had actually suspected a bad balancer when I was setting timing on a 92 camaro with an L03 305 TBI. I was concerned that the timing was off despite having set it to 0 degrees BTDC with the EST connector disconnected and I didn't want to make the assumption that the timing mark was actually correct.
One theory was that, since the harmonic balancer is two pieces with rubber separating them, that rubber can go bad and the outer piece can slip. This would cause not only the timing mark to become inaccurate but also the balance would be off.
So there's a test you can do. Engine off, pull the plug on the #1 cylinder, rotate the crank pulley to a few degrees BTDC on the timing mark, and what I did is I put my phone camera down next to the spark plug hole so I could see the piston moving, then I turned the engine to 0 degrees on the timing mark, stopped, made note of where i was to the camera, then continued past it. If the piston moves upwards before you hit 0 on the harmonic balancer and then downwards after you hit 0, the balancer has not slipped. If it keeps moving in the same direction or you see it change directions at any point that is not at 0 degrees on the balancer, the balancer has slipped and you can be absolutely sure that you need a new one.
Turns out in my case it had not slipped and I was just making things up - the issue is something else entirely. And by the way, there was a point where someone had swapped plugs #1 and #2 (these are next to each other on the same bank in this car) causing a misfire on both cylinders and that made the car shake a lot. Since you said fuel trims seemed good that's probably not the problem.
@@polymetric2614 thank you for the detailed response.
I formed a lot of rust on my balancer. Sounds crazy but I wonder if the extra weight of the rust buildup could cause it to be out of balance.
um I think it would be a good idea hear to add to the balance test. that putting it on a charger is always a good idea. false readings from a under charged or weak battery is possible and could lead to a bad diagnosis. I think your channel is leaning towards entry level technicians mid level wich I think is totally awesome but this was learned the hard way. its amazing what you will remember from a you tube teacher
Justin that's a great idea. I can see how this is possible especially considering you are in KOEO for the duration of the test- the last injectors done might be performed under weaker battery than the first ones.
How to find out the expected range for mass airflow sensor if the manufacturer does not provide the figures? I have 1999 Golf IV with 2.0 petrol engine, I have rich fuel trim at 22% on load, there are no driveability issues. I tried to clean MAF as instructed, but the problem still persists, I thought to test the output values and find if they are reasonable. On idle they are 7.5 celsius, 3.5g/s airflow, but under load (3k rpm) it is 55g/s. I tried this formula Volumetric Efficiency Calculator | OTC Tools. It says that the output of this formula should be 75-90%, but putting my data it is about 60%. Does it mean that MAF is bad?
You proved that the filter isn't the cause of the pressure drop in a static situation. I agree that the pump is bad at this point, but a clogged filter could be responsible for the failure. A flow restriction at the filter would cause the pump to run at a higher than designed pressure/duty cycle which would shorten its life.
I posted this on my phone, and I'm not sure how it ended up here. This reply was supposed to be for the jeep video with the bad fuel pump.
Dennis Rindlisbach That's OK. Fuel filter restriction is ruled out though, because I tested pressure from the pressure line before the fuel filter and got exactly the same reading. This eliminates any restriction in the entire fuel line.
Well this made me feel better of my 3 months diagnosing a problem with my friends kia lol
i consider plugs and wires to be normal maintenance items that should be replaced anyways if you never have done it on the car. it may or might not fix the problem but if you never have done it to the car there is a good chance it needs it anyways. if i had a misfire code i would run the car at night to see if their is any arching
andrew donohue my wife's 1996 bonneville was throwing a P171 mis-fire code and yes i did replace the plugs and wires and yes it did fix the problem but we have driven the car 30K miles and never did plugs and wires to the car. if that had not fixed the problem i would have continued with some reasoning and logic. when i replaced the plugs and wires i used reason and logic to come to the conclusion that the car was stumbling really bad, was throwing a code and i never did plugs and wires to it so it was overdue anyways
Reason and logic requires that plugs and wires would be the ONLY possibility. How were other possibilities of all the other parts that also weren't changed out ruled out? How did you logically rule out fuel pump for example?
if i had done plugs and wires which had allot of miles on them anyways and i still had a problem of, course i would have continued on testing. it was a P0301 meaning only one cylinder was affected so its unlikely that would be the fuel pump as that would effect ALL 6 cylinders and would have been a P0300 generic misfire code. i would hook up a scantool. i would look at long and short term fuel trim. being that only once cylinder was effected it would probably be plug, wire, or injector. you could also hook up a niod light to make sure that injector is in fact getting its pulse. also if i moved the wires around the code would go away and the car would run better. other things you could do to check for a bad wire include spraying them with water, watching the car run in the dark. it will light up light a Christmas tree if the wires are bad, in fact i think i did that too
+Schrodingers Box i'm learning english and mechanic at the same time , thanks men from south america , we need more people like you in my country ,!!!!
Schrodingers Box
of course we know that plugs and wires aren't a cure all for every problem, that's just un-reasonable and illogical. in that case i could hear snapping noise that was coming from the ignition wires, it was a pretty good indicator. one of my other vehicles was recently suffering from a mis-fire. that car also needed plugs and wires, it would act much worse when the weather was damp or wet. again my suspensions were correct plugs and wires. aged ignition wires are susceptible to moisture and engine load. if you have bad wires often times the symptoms will get worse when the wires get damp. they car also ran worse under a load, usually that's ignition related. had the $30 plugs and wires not fixed the problem, my next step would be a fuel system pressure test. when i buy a car relatively cheap and it has allot of miles on it, i will assume that eventually it will need wires. the car in question is a 2000 GTP and has 162K on it. the wires were the original ( i suspect) ac delco wires that were numbered for the cylinders. 162K i think they had a good run
Always love a good Kilmer channel jab. I get annoyed whenever I'm watching quality diagnostic videos and his trash gets recommended for me to watch. I always have to stop myself from clicking on the video just to comment.
Lol yeah he is the index case for parts changing mentality.
@@charlesgould8436 I'm not convinced he was ever a mechanic. His videos are mostly opinion based and sometimes flat out wrong. It's always a good idea to avoid a video with a title on how to fix something. The good videos are titled, how to diagnose something.
1992 Voyager 3.3 Liter V6. Starts OK, Will Idle for about a minute until stalls as the IAC opens and the motor can not respond appropriately. No distinct miss at idle , just struggles to keep idling, notable heavy modulation of IAC trying to maintain idle, application of throttle brings about severe misses /missing, pops and sputters, intake back fire indicative of over lean condition at just barely above idle, very hard to gain any engine speed/ rpm, IF the engine does manage to get above 2000 to 2500 RPM ( estimated because there is no tach) THEN engine instantly smooths out and runs normally /revs aggressively in high contrast to horrible stumble in region of just above idle to 2000 RPM.
(I admit that I already did the part swapping gambler approach that you do not like, with no remedy on my part) Already changed TPS (new) no remedy took it back (Thanks AutoZone) , Map Sensor (used from Wrecking yard) and ECM ( used from wrecking yard). No change noted as mentioned parts were replaced. Checked for vacuum leaks in area of Throttle body with unlit propane torch, no effect noted. Contemplated EGR problem. Checked engine for EGR. Apparently this engine has NO EGR system. At this point wondering about any possible IAC issues / suspect of Junk Yard MAP. I tried some stuff, with no success. Seeking outside input at this point before proceeding any further. Can a faulty fuel pressure regulator cause that kind/ degree of problem? I am doubting it. Can a faulty O2 sensor cause that degree of problem? I am doubting it. Crank Evac check valve ? I am doubting it. Anything else ? Thanks in advance.
Up date: Watched the video on fuel pressure regulators on this youtube channel. I am doubting that is the problem. FPR are to drop fuel pressure, so if they fail there is no pressure drop resulting in a rich condition. It appears that I am dealing with a lean out condition. The My next planned move is to test the MAP sensor with a multi meter.
Yes you actually have no data at this point. you need data to determine a direction.
I hooked up a Multi Meter to the wiring leads for the MAP sensor. It showed 5 volts supplied to the sensor. 4 volts at signal wire with engine not running but key on. Idling 1.5 volts, 2.5 volts shown on throttle blips. I did not take the engine into the RPM range where it smooths out and runs well, so no Signal Volt reading there. Maybe I should have. Problem still exists, as the MAP sensor appears to be functional as tested.
Yep- at this point you can rule out MAP sensor. Now you need to do a fuel trim analysis.
So I will watch your video on fuel trim, and try to get more savvy on the subject. I am trying to take the initiative. thanks for your attention thus far. You have been infinitely more helpful than the Chrysler Minivan Fans forum. I really want to solve this problem. It seems to me that I am working with a lean out condition being the problem as indicated by the intake popping opposed to an overly rich condition which would make heavy dark smoke with heavy gasoline smell and more even /general sluggishness.
The O2 sensors get dropped out of the loop when you go WOT as the PCM goes into enrichment mode. Whether or not the O2 sensor still report the correct value I'm not sure
they do. They will accurately report rich at WOT.
What happened to part 3? Just watched parts 1 & 2, would love to watch the conclusion. The link doesn't work.
lmao at 25:40 re shrader valves - yes, I find this very frustrating as well, my car lacks one
Scotty Kilmer... I understand now.
Right!!!!!!!
I have Mercedes C180 model 1999 I have error P0170 my STFT is changing normal when I press the accelerator paddle from - to + but the LTFT is fixe on 0.8%please can you explain why and what will be the error
Scotty Kilmer told me to swap out my plugs and ignition wires!!
HAHAHAHAHA--- Yes he is the index case for why everyone that walks into an AUtozone buys plus, wires, and O2 sensors.
I am glad you realized that it was a joke!!! I LOVE your videos!!!! Keep up the good work.
It truly reminds me of Arthur C, Clarke when he said:
"Any sufficiently advanced technology is indistinguishable from magic"
I feel most people consider modern auto mechanics as . . . "MAGIC".
CHEERS!!!
Uncle Duke
hmmm, my Sports Doctor said I need more parsley. What that has to do with the car I have no idea.
the bruthus on. In my case, I hope right now, is the damn engine either has a stuck open thermostat or NO thermostat. The engine is running at 130 F degrees, per what my tool says, and the temp gauge on the dash is barely reading off of low. The cabin air is not all that hot either. I cant fix my lean condition until that is correct, and maybe it will go away once proper temp is reached. I wish this guy was my neighbor. oh I failed because on another video I did say fuel injector cleaner. I only say it because I get better MPG if I put that stuff in once a year and I've cleaned many an IAC valve from garbage in fuels. Not looking for an argument, I know fuel injector cleaner isn't a fix all and should not be used as such.
If you play cool, you can develop a training diagnostics simulator i think
Omg yes on the Schrader value. My friends 2005 kia sportage 2.7L needs a adaptor tool that cost $100. Fuk you kia! I rather throw in a new fuel pump assembly. Hear me out lol. It has the fuel pressure regulator and filter built into the assembly. It has never been changed and has 90k miles. I rather waste my money on that instead of a tool ill never use again lol.
Link to next video is broken- Copying the video-ID - 5WHih2X-WS8 - and search for it on youtube gets you to part 3.
Thanks! Will fix that!
There's my very handsome man...
I like that Trans Am, though.
Help plz. 2005 Corolla with p0171. So far have changed the maf with Toyota oem part. Replaced both o2 sensors with denso. Changed intake gasket. Changed catalytic converter due to a leak. Fuel pressure reads at 49 psi. Removed and cleaned fuel injectors. No vacuum leak. Car running very rough at idle. At idle, short term fuel at 0 and long at 25. At 2000 rpm, short at -4 and long jumps to 40. Any ideas plz.
What was the data you got that indicated you needed to change the MAF? What was voltage and frequency? What was the LTFT and STFT curves idle vs load? You need to start with that data because you clearly overlooked something causing false diagnosis.
10:44 I think you jinxed the no misfire a little too much, there is indeed a misfire in cylinder #3 ;)
Hahaha never even saw that!
How do you deal with someone who brings you a poor running car, that hasn't had service in a long time. Would you advise a service first before diagnoses or just go straight into looking for a specific problem?
it is completely irrelevant. I simply gather and interpret it independently without bias like I do any diagnostic.
Thanks
thank you. always
What will happen if you swap O2 sensor leads. Not the sensors. Just only O2 sensor leads..
Hahahaha not sure why you would do that but I can assure you than unless both banks were perfectly 100% tuned the car would run terrible. The reason being is think about it- one bank needs just a very slight fuel trim so the PCM adjusts fuel trim on that bank. BUT the OTHER O2 sensor sees the adjustment. So now THAT bank gets an adjustment which is seen by the first O2 sensor but it isn’t the adjustment called for which in turn calls for another adjustment which is again seen in the wrong bank and the procedure would repeat until both banks had their trims maxed out in opposite directions.
A test failed is not a failed test!
Oh man I like that!
Sea foam didn't fix it?
Hahahaha. I have never even once bought a can of that ish. or is it on a bottle. I don’t even know lol.
SEA FOAM= Someone Else As Foolish Offered Advice Moronically.
P0171. And misfire codes
Ltft at %40 Stft around % 0.
I've changed ignition coils and maf
I notice o2sensor bank 1 s1 is at 3.1v idle and bank 1 s2 is at .07v idle. Is it my oxygen sensor? I press gas and b1s1 moves normally but b1s2 graph is straight Most of the time
Toyota Corolla 2007
You didn't include the data that indicated the coils and MAF were bad... where is that?
@@SchrodingersBox I replaced the coils and maf sensor and thought it would help as they never been replaced. It improved performance a little bit but I'm still getting p0171 and misfires. I notice that my b1s2 voltage doesn't move at as quickly as b1s1 and looks very blocky on the graph
@@jaggerc.2017 Well thats a guess- not data. I need to see data such as induction metrics and the fuel trim data to make any judgements. Without the foundation of basic-level data you can't even get a direction on what the issue could be. I need a basic starting point.
spot on!
i have ran across carbon build up cause the fuel stream to form a drip at high end load
The data clearly shows this cannot be an injector fault though. Look at the fuel trim and also where is the misfire count?
I agree you with at 7:01
I am sorry but if you are going to be fully methodical and scientific, the 2nd guy is completely wrong. The only thing he verified that the ignition cable had no continuity, so he knew the cable was faulty. BUT he did NOT check anything else. For all we know, more parts could have been wrong. Your second guy is "Scotty Kilmer" in desguise! Actually, I personally have no problem with him and appreciate his videos for the complete non-sense approach to fixing ones *own* car in less than 270 seconds or less :-) Heck, his clutch replacement video was the shortest video ever shown on youtube for any clutch replacement :-)
If you want to take shots at others, then show the stuff where not only you diagnosis the bad part, you also rule out all the good parts. I hope when you work on the car, you are the 1st guy and NOT the 2nd one!
But the second guy did rule out that the were no other causes. When he replaced the faulty wire and ther was again spark, it confirms there MUST also be coil control, coil spark, plug spark, fuel, and compression
OK, so he replaced faulty wire and then car ran OK, so obviously that was the only problem in *this particular* case. What if he had to order the $300 wire and had a week long wait on it? He needed to make sure that was the only problem before ordering the parts. Otherwise, how is he different from the Kilmer guy? No, he is a part swapper but at least least he is swapping a bad part after making sure the part was bad. Once again, I expect a logical person to make sure not only is he replacing bad part, he is making sure he has verified that there are no other bad parts before he replaces a known bad part.
Yes, replacing the wire here was trivial and cheap but we are talking about principle of diagnosis here not how to get the car out of shop and make a quick repair.
I would expect a competent person to verify bad part and also make sure everything else is working correctly before ordering the replacement. If the wire AND spark plug were both bad, he would have replaced the wire and then swapped the spark plug etc. Nothing wrong with that bad part swapping approach but let us call it what it is.
Yes I see your point- the whole idea was just to make a point with the moral of the story and not focus on the actual case study example. I should have pointed out the misfire example was strictly a no-spark one I guess lol.
Hello I have a problem with my 98 bonneville 171 code and multiple misfire code I have changed all spark plugs and wires and coil packs I checked the fuel trim short term is 25 at idle goes to 0 when 60 percent throttle long term is 16 percent I checked fuel pressure 48 psi fuel pressure regulator is working I have checked for vacuum leaks at intakes and all vacuum hoses no leaks detected I can not figure this out can you please help ?
See my video "secret of engine proble. diagnosis:fuel trims" and it will clearly show how to properly collect and interpret the data.
mark hernandez dgk
Fuel pump
Damn! I love this guy. No homo.
hello I got a p0171 on a V6 engine bank one could a exhaust leak between the two O2 cause this problem that happen after cleaning the catalytic converter I was getting p0421 and p0431 that is fixed for now.
dany ordonez No a leak between the O2s would not cause this. Did you confirm from your rear O2 sensor trace that cleaning the cat actually fixed it?
Yes by cleaning my catalytic converter got rid of the codes p0431/p0421 but after putting the catalytic converter back now I got code p0171 on bank 1 fuel trims are short trim at 13% and long at - 12 % there is a exhaust flange at the end of the catalytic converter between the two o2 sensors.
By the way I drove the car for 80 miles and ran the engine to the next day and they only code keeps coming up is P 0171 Bank One
dany ordonez What did your static vs load fuel trims show?
Didn't check I'm still learning started working on cars last year
Good video
Why is part 3 video not available?
it is- see the video description for the continuation link.
I got it. I was looking in the video description and that one is gone
@@SchrodingersBox ty I absolutely love your videos. Your the only one that's been able to teach me this stuff.
I do get that a lot. glad we connected!!
@@SchrodingersBox I have a mystery po171 131. I've replaced entire exhaust system manifold back. No vac leaks from. My test. Fuel pressure is good. New 02s good clean MAF new temp sensor. Only thing I haven't checked and can't is injectors. I have driveability issues. My fuel trims look good. 2 things I can't check ans not sure about is the Injectors and pcm. It's a chevy 6.0 vortec. Simple engine. But I'm lost. It's been to a Few shops and they just throw there hands up and say just run it it runs fine. Smh. It runs pretty good. But do have driveability issue. Just seems to struggle. Merry Christmas man
you loooove scoty;D
Hahahaha that guy is a lizard. He preys on the ignorant.
@@SchrodingersBox yeouch. 😀
I cleaned maf sensor I thought I should say
i am looking very good mechanic like you in arizona,please let me know if you have friend (mechanic) he do great job like you. i have same problem with my 2007 escalade esv. Thank you
I travel to arizona for business every few weeks. I'd be happy to look at your car. PM me.
thank you
thank you for this videos i want to ask about cleaning O2 sensor is it right is it work any one test this before
Either way... if cleaning an O2 sensor worked- which it doesn't- the fact you would need to clean it indicates there is a A/F ratio condition requiring correction anyway.
In other words- cleaning an O2 sensor will not fix the cause of a problem.
thank you sir for your reply
👊 in the throat! 😆
Try using seafoam!
or a steam machine
love your channel, very informative but lay off scotty im sure he forgot more than you can do with your computer and dry erase board.
Ill keep watching for now. A man i once worked for told me anyone can be a mechanic as long as you have a computer. the key words are" once worked for"
I highly doubt scotty forgot more than I know since he wouldn't know how to diagnose a P0171 to begin with- he'd just change the O2 sensor.
If he forgets how to that he's in big trouble since parts changing is all he does.
check exhust bolt broken mouth of the u tube