Diagnose a Misfire LIKE A BOSS (DIY vs "Pro" Mechanic!)
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- Опубликовано: 27 июл 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 
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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!!
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.
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
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.
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
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…😀
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!
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.
Fantastic video as always Matt, loved that you can see a fuel issue using the scope I didn’t know that! Cheers.
This is the type of professional work people need at shops. Great video thank you!!!
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!
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!
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.
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!
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
Great diagnosis Matt. To the point and no BS 😁 Thx! 👍
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...
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!!
You're a mechanic people could trust you with their cars. Good job.
Thx for being yourself.. one of the genuine folks out there
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.
Brother! Gratitude, love and appreciation. Perfect example being the change we want to see.
Thank you!!
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.
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!
Awesome channel keeps what learned fresh and picking up new knowledge.
Good work Matt! Looking forward to joining the new channel.
Nice video bro thank you makes it easy to understand your method of diagnosis! Great to the point diag
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.
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.
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!!
Nice work Matt! Super common on these GM's.
Love the shirt, only from a scientist! Oh yeah, great video too!
This freakin Dude is awesome. He's a trip. Featuring old school with new school applications.
Fantastic as always Matt!
'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!
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.
Good information man ! Helpful for a growing diy guy
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.
Good Job Matt. Looking forward to your new channel
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
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
I just want to thank you for taking the time to teach the average guy to get us to the next level
Needed this today. Great video and as always thank you for doing these and walking us through this...
You are so welcome!
Awesome little learning gem & excellent coaching ! I’m binge watching ! 😃 Feeding the hunger ! Thanks !!
I know the feeling lol. Enjoy!!!
I have a 2014 Dodge Grand Caravan SXT in the repair shop as I’m writing this for a Cylinder 5 misfire which is not intermittent, you can feel it at idle but not so much when driving. The shop replaced the fuel injector because the ohms reading was 3.6 compared to the 3.0 on the others they suspected a bad spray pattern could be the fault. That didn’t solve the problem. Next they removed the valve cover to inspect the camshafts and lifters they claimed that this particular engine has a high failure rate. All the lifters, camshafts and springs appeared fine, they used borescope to inspect the valves and no damage was found. They reassembled and test drove the van and they say misfire disappeared after hard driving and said that indicates carbon buildup on the valves causing the misfire. They did a carbon of the van with a “BG” product. They test drove the van and said all was good. I picked up the van and after just about two miles the check engine lamp came on and I stopped the van and plugged in my basic check engine tool and it had the same P0305 code! Now the shop is telling me that the cylinder head may be bad and needs to be sent to a machine shop for inspection and repair. I’ve lost all confidence that they can fix the root problem at this point so I need a second opinion. Do you think this cylinder head could be the problem? P.S. I forgot to mention they did a leak down test on the #5 cylinder and it passed, and said valves were sealing.
not sure what to say but before all of that, they should be able to narrow it this is a fuel, spark, or compression issue. that is the very first step. they have to determine which of these it is before proceeding. if they can’t do that, someone else needs to look at it.
Today is the first video I saw, and right away I have subscribed your channel.
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.
this is a really good video! people like this guy are genius appreciate the video!
Thanks Matt for another fine video.
Awesome. Can't wait to learn more. Thank you for your work and channel.
My pleasure!
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.
Hey nice find there Matt. Like a boss!
Thanks Ozz, good to see you back!
I like the dedication and commitment to your beginning community. Subd outta respect. Keep it 💯 👊
Great demonstration.
Great video, great knowledge!
Thank you Matt. Good job. Appreciate your videos. Bless you and your family.
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.
Thanks for this super video :) I'm ready to your new webside from Copenhagen Denmark
Great vid, looking forward to your teaching page.
THEY'RE BOTH GREAT CHANNELS.
Good evening sir just another Mastertech with my two cents good thing to tell the DY is you can pull a single injector wire off on each unit without the risk of hitting 10,000 KV from dis ignition, continue to pour each injector wire to listen for change and when you pull in injector wire with no change that is your cylinder misfire. All the basic diagnosis fuel compression injector pulse which is the grounding signal from the PCM flashing injector for on-time same thing happens for the coil I’ll call Elsa hot from the PCM they are used as a ground sink from the powertrain control module have fun guys.
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 RUclips. 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.
Thanks bro am going to check it out
That was a great video... and a great shirt as well.... Rock on mate!!!!
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!
Hi I’m new to the channel you’re extremely knowledgeable I like your style Of teaching and explaination
Subcribed!
This dude's a genius
Great Video very informative
Thank you. Great information. Learned more on this video then my
AUTO CLASS
Glad it was helpful!
Thank you Matt
Matt, hello been long time first want to congrats you on 100K sub and thanks for loading such suburb video full of excellent info for diyer always waiting for the next one thank you and cheeeeeeers.
Thanks man, and thanks for your years of support! You're always one of the first to watch new releases!
THX! for the ideas on troubleshooting. outstanding.
Nice very good info 👍
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.
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.
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).
Good show, thanks for sharing!
Glad you enjoyed it
Much better video than last time. I'm glad you got rid of it. This is more like you. Thanks.
I loved that last video! It was hilarious!
I know you had fun with it and you always have intelligent replies to the haters. It just wasn't why I signed on to your channel and recommend to others.
Understood bro. Actually my advertisers felt the same way apparently as they let me have it and threatened to pull back from the channel so I definitely had to remove it lol.
You are a really good Mechanic
Great video!
I subbed bc I learned about using electronic gadgets to troubleshoot electromechanical systems. Nice!❤
Your starting sound like professional 😂
Great video. I'm currently searching a misfire on my 90 GT Safari. Brand new engine one year old. Lots of new things also like water pump yada yada yada. I'm almost positive out of laughs that it's being just almost exactly the day of a year of the repairs that something failed because it had a year warranty😅😅😅
If it was under warranty they should fix it. Or better yet just determine the cause of the misfire and tell them what it needs
I love the scientific approach. I still do not completely understand how diagnose electrical problems, but your video series has gotten me miles ahead of where I was as far as diagnostic capabilities. Is Quantum Mechanix going to be an actual website or a You Tube based channel?
ACtual website. and on it, you WILL be able to learn to diagnose electrical problems every bit as good as I do. It's all about understanding the fundamental concepts. Once you do that- you can choose any way you want to do the diagnostics based on your available tools. I could have done this with a multipler, a scope, a test light, jumper wires....
Man you are a smart guy this stuff takes time to learn not easy for a beginner its a lot to remember theres got to be a faster better way than using a scope
yes it takes me several times to learn it too.
what would be faster that using a scope for this though and having 100% confirmation this was a fuel issue?
@@SchrodingersBox thanks fot the reply i am learning from scanner danners engine performance diagnostics book it gets confusing because there are so many different ways
oh yeah for sure. there are many ways to do lots of this stuff. if you understand the principles though, they all make sense. it’s seeing the picture instead of “painting by numbers”.
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 troubleshoot! Thanks
You're welcome!
Thanks Matt.
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
Love your videos,love the shirt
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
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.
APPEASE US OHH MIGHTY APPEASER!!!! 😂
Great video
😂
Very good Matt
Great diagnosis
Thanks, my wife's 03 Saturn ion 2.2 ecotec engine has an intermittent bad miss but it typically only happens above 3500 rpms and not all the time. One cylinder did have around 150 compression(#4) and the other 3 had around 200-205. Code wise it has the Cat efficiency below 95% and occasionally, If I remember right the code for "random missfires". Thanks. I enjoy your approach to diagnosis.
Exselete diagnostic Tec. Nice video
Great video bud