Diagnose a Misfire LIKE A BOSS (DIY vs "Pro" Mechanic!)
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- Опубліковано 5 лип 2024
- Do It Yourselfer diagnosing a single cylinder misfire on a Chevy Suburban that a "professional" fired the parts cannon at by replacing plugs and wires (pretty much the status quo for hacks, ain't it?). Can a DIY diagnose it any better without playing the parts lottery?
See these other channels for more great auto diagnostics!
Stuzman (Automotive Electrical Engineering) / stuzman52
Spelunkerd (General fix it of just about anything)
/ spelunkerd
Schrodinger's Box website: www.schrodingersboxqm.com
#pnsearch - Авто та транспорт
Man, I wish I lived close to this guy so I could pay him to work on my car. What a great mechanic & a cool channel.
he didn't show where he clamped the stuff
Me to
I would happily pay him to just diagnose mine with his scanner, I can do the labor if I know what to replace
Where are you located
Denver colorado.
Got a cylinder 1 misfire on a 2010 challeneger v6, your videos really help me become a better technician and make sure I get the diagnosis right the first time. I'm definitely going to thoroughly test everything before just throwing plugs at it or something it's what my customer deserves. Thank you for these videos man I'm a huge fan of you work. I find the actual diagnosing part not only necessary, but extremely fun and engaging.
Thanks man!!
Matt, I greatly appreciate your gift for teaching and explaining the way things work, and how to properly diagnose problems. It’s good to know the “why” and not just the “how”. You don’t simply “shoot a parts cannon” at the problem. Your time and effort to provide information on this channel is exemplary. Thank you for all you do!
Qpa
Great teacher
Thanks for the shoutout, Matt. You showed another quality diagnostic video, what we're all looking for. The lean pattern jumped out with a snap throttle, great case.
0+0
Another great example of how science wins the day and clearly shown through your methodology. It was nice to see your dedication to the two channels at the beginning; a thoughtful touch. I’ll be sure to follow the links to their sites. Many thanks Matt.
Okay good one Matt! Glad to see you're excited and ready to go with the new channel.
Great info here! I learned a lot from this guy, so whenever possible, i watch the ads to at least give back to this helpful friend.
I have a misfire on #3 Mecanico replace spark plugs and coils; and nothing changed, I took the car to my house and this was a great profesional information.!! Thank you , you have your self a new follower.!
I’m going to check injectors next…😀
This is the type of professional work people need at shops. Great video thank you!!!
Fantastic video as always Matt, loved that you can see a fuel issue using the scope I didn’t know that! Cheers.
I, for one, very much enjoy scope based diagnostics, which i appreciate you doing matt. It covers everything, you can see the coil operating well, the oscillations at the beginning of the dwell segment and also at the end of the firing line. And the importance of establishing a baseline. Those are absolutely fundamental to secondary ignition waveform diagnosis. Keep em coming, great stuff. Maybe you'll indulge us to more scope based diagnostics, current ramping, primary and secondary waveform diagnostics, and maybe even in cylinder transducer compression waveform for those mechanical issues. It's be inferesting to see more of your take on these approaches.
Couldn’t agree more man! My original thinking of “most of my viewers don’t own a scope so i wont use it” was flawed. The scope is actually one of then best training tools because you can “see” the behavior of the voltage and amperage and how they are related to resistance variables. Yes i will be using it more, but mostly to explain principles.
Looking forward to it!
Nicely done Matt . Two terrific mentions and congrats on 100K , you have put in lots of hard work and have had lots of fun along the way too . Cheers 👍👍
Thanks my friend! Good to hear from you again!
Loved this video. Great method of diagnosis by process of elimination and logical reasoning. Brilliantly done.
I don't think anyone should have to pay a professional who's method of diagnosis is throwing parts at the problem and hoping. Anyone can do that. You pay a pro because they have the equipment but more importantly the skills and brainpower to identify and the positively isolate the problem first time. That's their trade after all.
If a pro replaced 4 spark plugs and all the wires and the car is still mis-firing, why should they be paid? Mechanics are hella expensive.
Absolutely agreed!!! Thats exactly why I made this channel, so people could have an option!
COOL! All this stuff new to me. I like your confidence and explanation. A good teacher, one who know s the subject, makes teaching understandable to us tyros. Thank you.
Thx for being yourself.. one of the genuine folks out there
Awesome video! This mechanic is a expert and explains things clearly !
That was a great shout out for some exceptional channels. Now back to the video...
You're a mechanic people could trust you with their cars. Good job.
Great diagnosis Matt. To the point and no BS 😁 Thx! 👍
Brother! Gratitude, love and appreciation. Perfect example being the change we want to see.
Thank you!!
This video was the straw that broke the camels back for me. Thought I could avoid it for years but my jaw dropped when watching this one. I went and joined the pay channel. I would love to be this fluid, dynamic and precise with auto troubleshooting.
Now you will!!
Checking the coil that way would have saved me a trip to the part store and about an hour and a half laying comfortably across my grill and air box last night
Awesome channel keeps what learned fresh and picking up new knowledge.
In the beginning I thought I wasn’t gonna learn a thing. Yeah this dude is smart as shit. I’m impressed. Subscribed
yEAH, What he said.
Good work Matt! Looking forward to joining the new channel.
As Einstein once said "If you can't explain it to a six year old, you don't understand it yourself". Well Matt, you certainly understand what you're doing because I'm as green as it gets with auto fuel/electrical systems, and I understood everything you did. Exemplary Job!
Thanks, thats a great compliment!
Thank you for this video, as i have exhausted all my other options. Because I too just throw coils and plugs to fix this in the past.
'Yeah, I meant the coil in the injector was bad'. Great video Matt, looking forward to the pay channel.
Dang actually you know what- I wonder if it’s possible that is what he meant and the owner miscommunicated it??? Oh snap lol!
Love the channel. Checking the injector eliminates poor terminal tension between injector and connector, nothing like having a comeback a week later on something you were positive about.
Ah good point about the terminal connection- very true. The resistance test is not excessive after all!!
Love the shirt, only from a scientist! Oh yeah, great video too!
Nice work Matt! Super common on these GM's.
Nice video bro thank you makes it easy to understand your method of diagnosis! Great to the point diag
Anytime I've run across a single cylinder misfire, I've always swapped coils with an adjacent cylinder to see if the misfire follows the coil or not before deciding that the coil is suspect. Learned a different, more efficient way today, thank you! Also, feel the need for an oscilloscope!
Yes i normally do that as well but in applications where the coil is below the plenum it is way better to do testing like this.
I just want to thank you for taking the time to teach the average guy to get us to the next level
I have a 2000 Dodge Durango with the 4.7L v8. I had a single cylinder misfire on #1. I tested the resistance on the all the ignition coils and fuel injectors as well as the voltages on the harness. Voltage was good, but i went to do a continuity test on #1 injector, it was completely dead. I had an open circuit. I suspected it as i had a check engine light for cylinder 1 fuel injector circuit. I tested it because i didn't know if it was the injector or the voltage.
Fantastic as always Matt!
This freakin Dude is awesome. He's a trip. Featuring old school with new school applications.
Good information man ! Helpful for a growing diy guy
Awesome little learning gem & excellent coaching ! I’m binge watching ! 😃 Feeding the hunger ! Thanks !!
I know the feeling lol. Enjoy!!!
Matt, long time fan, lurker, and borderline on Quantum Mekanix. I DO really like your methods. I have the same truck, same motor. This might tip me over to being a paid sub to QM. Enjoyed your vid. Thank you!
Hi Matt my friend has a Renault Espace 2.0 turbo 2005 when he brought the car to the mechanic the windscreen wipers wers not working( no power to electricity connection to the wipers motor), fuses were and are good. so the new software to the UHC ( one of three contents od the Comfort Module ) was installed. After that the wipers are working, but there is no connection with climatronic now( not even a display). Shoud there be another software installed now, or should we check in other direction? Thanks
this is a really good video! people like this guy are genius appreciate the video!
Good Job Matt. Looking forward to your new channel
I just learned so much I think my head exploded all you need is a little product awareness logical and you rock man you just rock thank you so much
Needed this today. Great video and as always thank you for doing these and walking us through this...
You are so welcome!
Today is the first video I saw, and right away I have subscribed your channel.
THEY'RE BOTH GREAT CHANNELS.
That is so cool to mention those guys. Both have awesome channels. Now as Wyatt said, back to the video!
Nice job for a DIY'er! Now I am going to have to give you that $3.99/ month. Damn! BTW-- good video! Congrats on the 100,000+ subs.
Thanks Matt for another fine video.
Great demonstration.
Hey nice find there Matt. Like a boss!
Thanks Ozz, good to see you back!
Awesome. Can't wait to learn more. Thank you for your work and channel.
My pleasure!
Nice video. Might want to mention though that it can be harmful to use test lights with low impedance on computer circuits. That's why I just like to use my multimeter. They do make high impedance test lights though.
Hello I have same issue with my dodge grand caravan . But how often do you need to replace cinlinder head ? When no fluid shown thanks in advance
I like the dedication and commitment to your beginning community. Subd outta respect. Keep it 💯 👊
So you could have made the same diagnosis by elimination alone. What sort of a mechanic must the first guy must have been. Another excellent video. My best from Scotland.
You always talk sense it makes you wonder how the “professionals” cope at all, keep up the good work 👍
It seems the only way to me lol! I mean- it's just so.... logical! How else can you know ANYTHING other than through logic!!
Guessing pisses me off lol!
I would guess that it should... LOL
BTW, great shirt, and great channel.
I feel like they bs you to keep up appearances and save face.
Thank you. Great information. Learned more on this video then my
AUTO CLASS
Glad it was helpful!
Great video, great knowledge!
Not too bad for a DIYer, just kidding,haha!! Nice diagnosis and follow up test to prove your theory. "Professionals" take note, this is how it's done.
Thanks ,i really appriciate you for such a simple and practical test and diagnostic method,
Just i 've been confuding when you're using the scope,i mean ,i don't know how to set up the scope and trigger to catch the wave form ,do me a favor with introducing a good surce to find out all the secret about how using the scope.
best wishes.
Your starting sound like professional 😂
Thanks for this super video :) I'm ready to your new webside from Copenhagen Denmark
Thank you Matt. Good job. Appreciate your videos. Bless you and your family.
If you find this useful please dont skip the ads so the guy gets a couple pennies atleast for the free info hes been giving to us so generously
Thanks bro am going to check it out
Great vid, looking forward to your teaching page.
I changed my ecu and 6 coils and still burning coils now after i changed last burnt coil car still hesitates what would be the problem and cause coils to keep burning any help please? G35 2004 manual
Very nicely done Matt with a clear and concise explanation. And great follow through with the procedures to coincide your explanation. Very nice of you Matt to give me a shout-out as it’s very much appreciated! The very best wishes to you and your family. And of course, I hope your new website will be a great hit. There’s going to be a lot of folks with vast amounts of new knowledge!!! 😀😀👍
Can't thank you enough Terry! I hope this brings you new viewership. It's true- I learned more about electrical from you than everyone else combined!
Schrodingers Box Always a pleasure to help Matt! Holler out if you ever need anything! 😀
Stuzman is the man with the electrical plan! Good to have great channel resources to get proper guidance and education from people that know what they are doing!
stuzman I wanted to make couple of questions on this video and since Matt don’t like stupid questions maybe you can help me with the following..
1) how did he know that the current draw of the test light was not going to damage the driver?
2) how base on spike on the scope he knew there was a fuel problem?
3) do you know where I can find information on how to read a scope?
Hi Tito and hope you're doing well! For question 1, most fuel injectors will run about one amp and most test lights are around 200mA. So the current draw of the test light is less than the current driver capability. So there is no problem in damaging the driver. For question 2, you noticed that the spark line was rising up significantly at the end when the RPM was increased. This shows that the cylinder was running out of fuel making the air-fuel mixture leaner. You also noticed that the spark line looked okay when the engine was idling. This is because the computer is able to compensate for a low fuel condition at idle. But when the engine speed is increased, the air will move much faster than the fuel. And by the time the O2 sensor sees the lean condition, the computer has to compensate. Of course with the air moving much faster, the scope is able to see this lean condition. And on question 3, it takes practice in learning to diagnose waveforms in what it's telling you. Some pretty good channels that uses a scope are here on UA-cam. Two channels that comes to mind are scannerdanner and south main auto. Of course there are quite a few others out there too. So a little searching and I'm sure you'll find them. Hope that answers your questions and good luck on your knowledge of learning systems.
That was a great video... and a great shirt as well.... Rock on mate!!!!
Great Video very informative
You are a really good Mechanic
THX! for the ideas on troubleshooting. outstanding.
Great video and analysis Matt, what backprobes do you recommend for these plugs?
The ones I used are from Hantek. You want to be extremely careful not to bypass the load in the circuit so as not to fry the PCM so i use these for extra protection.
Thank you Matt
Way above my head. This must be for people who are experienced at scanning. Thanks for posting though. I will check out the other channel.
Great shoutout at the begining. Dave has some excellent videos, I wish he made more of them.
Yes he does. and damn the quality of the video and audio kick your ass don’t they! It’s like blu-ray quality lol!!
Will you be producing any literature for the paid channel that follows the instruction?
.........Since, you know, you don't have another full-time job or anything.
I'm excited for Quantum Mekanix to go live!!
Thinking about it!
I had the same thing. Bright light on the constant 12volt side of injector but a barely seen filament on test light for the pulse side. Thank you!
That is what would be expected. The pulsewidth in the control side is just a few milliseconds so filament doesn’t ever heat up enough to light fully.
Hi I’m new to the channel you’re extremely knowledgeable I like your style Of teaching and explaination
Subcribed!
Great video!
Hey man loved the video very thorough and very good job explaining the situation. Question I have a 2020 Ford F250 and it had a misfire on cylinder seven took it into the dealership they are telling me The engine needs to be replace. Before I took it to the dealership I replaced all the spark plugs The spark plug wire and the ignition coil on cylinder seven still having the same issue. My question to you is have you ever heard of a misfire being a symptom of a dead or dying engine especially a 2020 Ford F250. 7.3 L with 75,000 miles and proper maintenance. Thank you
All…. The… Time. Usually I diagnose that a new engine is needed when I find low compression in the cylinder and I determine it’s a bottom end issue.
I would ask what specifically they found that suggests engine replacement. If it’s low compression in that cylinder then yeah, you have a major problem. If it’s anything else though, I can’t see that you need a new engine.
I subbed bc I learned about using electronic gadgets to troubleshoot electromechanical systems. Nice!❤
that vid made me subscribe, and I don't even have a misfiring engine. superb! thanks Matt
Hahaha well if you ever run into one you’re prepared!!
Nice very good info 👍
A 194 bulb with the leads pulled out makes a great noid light for injectors. Great Diag !
Yep that would also have been a perfectly good way to evaluate the circuit!! In fact that's how I normally do it, but I had a lot of requests for the testlight which is essentially the same thing (except I split it into feed and control side instead of one test across the connector like a Noid light would).
This dude's a genius
Great example of using all your senses to troubleshoot. They can all come in handy. Well, except maybe for taste.
Great diagnosis
Is fluke the only way to go. And is there waveform function useful while I save up for a pro scope I see it and it looks really difficult to use
wouldn’t know. i don’t own any fluke meters. My DVOM’s probably cost like $12.
Nice explanation
Very good Matt
What if it's a 4.3 engine fuel spider,how does one go about testing that system?
Nice troubleshoot! Thanks
You're welcome!
Great video bud
Nicely done. I woulda thought corroded terminal on the distributor cap.
8-D
Thanks Matt.
Good show, thanks for sharing!
Glad you enjoyed it
Excellent one.
How did you read the oscilloscope as fuel line problem?
Yes this was asked earlier, I definitely should have pointed it out in the video, sorry.
It’s because the spark line uses fuel as a conductor. without fuel, resistance across the air gap increases multiplicatively. If resistance increases, then voltage must increase as per Ohm’s Law. The “spike” on the spark line is the voltage increase.
Great video ,now who put 2 thumbs down? This is great information for the diy .
One of them was probably the mobile mechanic. The other was probably Scotty kilmer.
this assumes of course that he wasn’t the mobile mechanic lol