'09 Corolla misfire diagnosis

2009 Toyota Corolla that I received from a local shop who just installed new coils, plugs, injectors, AND a PCM. I walk you through the process that I used to diagnose the true cause of the misfire!
I should have explained one thing a little better though! I dont do leak downs at TRUE BDC! I do leak downs right after the intake valve closes. So as close to bottom as possible after the intake valve closes. Then make sure that you're aware that the air will cause the piston to be forced down so you need to hold the engine from rotating!
Autel MP408 used in this video:
amzn.to/2RnrGj6
If you're interested in a pulse sensor, like one used in this video. Leave a comment below and I'll get you contact information to a friend that makes a quality homemade one.
Also, if you want to contact me privately. My email is: [e-mail]
The views and opinions expressed are in these videos are my own, and have not been reviewed or approved by my employer, and do not necessarily represent the views and opinions on my employer.

[@BTCAutomotiveTech]

Great process Pat as usual. You do a great job in your vids. I do take issue with one piece however; doing a "leak down" test at BDC. Almost every engine, including this one in this 2009 Corolla has a valve OPEN at BDC. During the intake stroke, the intake valve is designed to stay open slightly into the compression stroke (after BDC intake). During the power stroke, the exhaust valve is designed to already be open before achieving BDC of the power stroke. Either scenario - BDC intake stroke or BDC power stroke - will indicate a false diagnosis of leaking valves. Leakage testing should only be done at TDC.

[@VoltageDropDiagnostics]

I agree with 99% of what you said. I don't actually do leak downs at true BDC. I spin the engine over until I can feel the intake valve close with air in the cylinder it is easy to feel. Then I go a hair farther to make sure that the valve is fully closed. I should have explained that a little better. But you can 100% do leakdown tests with the piston below TDC.

[@VoltageDropDiagnostics]

I just pinned this comment because I want people to see that you cant do leakdowns at true BDC. I also added a correction to the description. Thanks for the comment!

[@andrewk778]

As an old, lifelong DIY’er, I had to think about how I would comment on this video. You made this look easy. It WAS easy. You didn’t need a scope or a leak down tester. A simple cranking test revealed a mechanical related misfire. And yet another professional garage fired multiple parts cannon salvos at the car. I actually feel bad for the customer. Thank you for sharing your knowledge and experience with us.

[@DIYDaveOK]

Garages like the parts-cannon shop are what inspire me to continue learning to do what I can myself. Heavens, I'm a total novice DIYer and I could hear that compression issue when he cranked it, and I immediately thought the next step was a relative compression test. Surely any real garage worth their salt heard the same thing. Why on earth does *any* tech start throwing ignition parts at it? And a PCM?? They took that poor customer for probably a good chunk of the cost of a new engine!

[@VoltageDropDiagnostics]

This was easy, for me. And I see you commenting on a lot of other youtubers channels, which means that you also probably have a good base from learning from here. The sad thing is. Professional techs are too stubborn to learn. They laugh at people who watch youtube to learn and frankly, most think they know everything. I feel horrible for this customer.

[@DIYDaveOK]

@@VoltageDropDiagnostics Thanks! I *love* learning, and I have learned a *ton* from you, Eric O at SMA, and Ivan at Pine Hollow (to name only a few). Thanks for all you teach and share!!

[@briankotze57]

This info is priceless. Really appreciate all the effort you take in sharing this knowledge.

[@VoltageDropDiagnostics]

Thanks Brian! I am glad that you liked it!

[@JoesAutoElectric]

Awesome!!!! I love that your explanation. The fact that you recommend and engine is the best route to go with the miles. Nothing like selling a head or head gasket replacement and having a bottom end issue a few months later. Great job bro.

[@VoltageDropDiagnostics]

Thanks Joe!

[@ring-and-run]

Always enjoy your videos. I am a new subscriber to your channel. We know you know your diag. Loosen up, smile and have fun with your presentation. In my opinion, you are on the path to freedom, and thank you for passing onto us what you have learned.

[@VoltageDropDiagnostics]

hahaha! You have no idea how hard I try! My first videos that are no longer on youtube, I wouldn't talk in. I just used captions because I am so camera shy!

[@arthurfricchione8119]

Pat, excellent video and thank you for showing the pulse generator hook up and explaining the results. Appreciate you taking the time to explain. I like the Autel scope. Will have to look one up. Have a good one Artie.. I personally support and am also a member of his Premium class. Excellent tech like yourself. Thanks Artie ❤️

[@VoltageDropDiagnostics]

Paul is a great guy! I am glad that you liked the video! Have a good weekend!

[@billyyoder8171]

Thank you Patrick. Good job. Have a blessed and safe week.

[@VoltageDropDiagnostics]

Thanks for watching Billy!

[@isalmankhan1]

Thanks for sharing Bro👍 Very important stuff, by the way love the SD t-shirt😎 I'm a huge fan and an online student of SD, He's Awesome❤, God Protect Him & Bless Him for the great work he has shared with all of us❤

[@VoltageDropDiagnostics]

Paul is the best! Thanks for watching!

[@abraham01257]

Well done Pat, as always easy explanation and great explanation of waves . Thanks again

[@VoltageDropDiagnostics]

Thank you! And thanks for watching!

[@weldingjunkie]

Common everyone hit that THUMBS UP it helps get PJ the credit he deserves. Nice job PJ, excellent info and keep up the good work. Your channel is very underrated for the amout of knowlage that you share.

[@VoltageDropDiagnostics]

Thanks buddy! I appreciate it!

[@PaulysAuto]

Excellent video Pat, alot of great stuff packed into this one!

[@VoltageDropDiagnostics]

Thanks Pauly!

[@gregjones8501]

Great diag Pat! Honest and simple! Diagnose it, inform the customer, move on! It’s how it should be done! ✊🏾

[@VoltageDropDiagnostics]

Thanks Greg! I truly feel bad for some customers. I truly do. They don't realize that not all mechanics are created equal.

[@gregjones8501]

Keep up the great work man! You’re doing an outstanding job!

[@smms5056]

I've got the autel scope in my line of sight, saving up to get it. So trying to learn as much as possible about it, while I wait. Thanks for the teachings, find your video lessons top notch. Thanks Man 👍👍

[@VoltageDropDiagnostics]

Right on You're gonna enjoy that autel scope!

[@seftonplayer32]

I just bought one myself and have tried a few simple captures. Still waiting for my amp clamps. The supplier is taking his sweet ass time. Nearly 3 weeks.

[@centrotecnicoautomotriz302]

Buen video, bien explicado y muy práctico. Excelente manejo de osciloscopio!

[@djosbun]

With yourself, Brandon and Paul leading the class, it will be like the Murder's Row of auto diagnostics! Hell, cars will self-heal themselves with the three of you standing in the same shop!

[@VoltageDropDiagnostics]

haha! I won't be teaching. Paul is doing a short presentation, and Brandon is doing his 8 hour class. I'll be there to learn with you all!

[@BigDogDiagnostics]

I’m trying to learn more on intake pulse testing. Really interesting to see how quick these tools make our diags, Thanks for sharing!

[@SuperMarioDiagnostics]

Great video! And AUDIO! Great analysis man, had that things fully diagnosed with the waveform. Especially with how common these are. I like that quick tip for the leak down too 👍

[@VoltageDropDiagnostics]

Thanks Mario! I am loving the new mic! Thanks for the help with picking out which mic to get!

[@SuperMarioDiagnostics]

Voltage Drop Diagnostics I'm loving it myself 😆 keep em comin!

[@kennygrant69kg]

Top quality diag as usual. Great process and brilliant explanation of the waveforms. As you say, it is sad that some technicians are not as thorough as they should be when it comes to diagnostics, especially if they are pulling the trigger on an ECU!

[@VoltageDropDiagnostics]

haha! I'm going to be honest. I have seen more toyotas with new ECUs that didn't fix the car, than toyotas that actually needed ECUs.

[@BigDogDiagnostics]

I’m so glad I found this channel! Great video man!

[@d.d4184]

Nice video pj thanks for explaining why you do the test at bdc. Best of luck with the training.

[@VoltageDropDiagnostics]

Thanks! I am going to make another video better explaining the process because too many people thought that I actually meant BDC

[@wyattoneable]

That was a great visual of the use of a scope. Thanks PJ!

[@VoltageDropDiagnostics]

Thanks Wyatt! I just got your sticker too. But forgot to send one of mine to you! Ill do that right now haha!

[@wyattoneable]

@@VoltageDropDiagnostics Looking forward to having it on my tool box!

[@bwdz75]

It is easy to overlook the basics sometimes, had a pretty good tech messing with a 2.0 ecoboost the other day swapping coils and plugs etc.. and I walked up and handed him a compression tester after listening to it crank from across the shop and it had 60lbs on cylinder one. Great analysis with the pressure tester. On a side note I have another Ford with the up side down back up cam image so I will try to scope it out before replacing it and see maybe why it inverts the image

[@VoltageDropDiagnostics]

Yes! Let me know! I haven't seen one of the cameras flip an image yet. I wonder what it looks like on a scope.

[@eFaZeHD]

Just come across your channel! Love the content keep it up! 👍

[@VoltageDropDiagnostics]

Thank you!

[@caliautotech21]

Another AMAZING video again pat! I’m just starting to get into pulse testing and it’s so interesting how much you can tell once’s you’ve got some experience! I’m in Cali obviously but I’m gonna try my hardest to make it to that class! Would be super cool to meet all the KZbin legends haha and that class is more than worth it

[@VoltageDropDiagnostics]

Cali Auto Tech i hope to see you there! Are you in northern, or Southern California?

[@caliautotech21]

Considered northern but I call it central lol.. I live about 30 mins from San Francisco.

[@VoltageDropDiagnostics]

Cali Auto Tech there is a big training event up in Washington state in the next few months! If you can’t make the training here, you might want to look into what they have to offer.

[@caliautotech21]

Thanks for the heads up!! I’ll look into it

[@michaelnicholson9092]

PJ well played brother on this video. 👊😎👍 Keep it my friend.

[@VoltageDropDiagnostics]

Thanks buddy! I am glad you liked it!

[@TheDisgruntledMechanic]

And very nice use of the scope and diagnoses using it.

[@VoltageDropDiagnostics]

Thanks TDM!

[@steveanderson4553]

Great Diagnostic Process !! Thanks for sharing !

[@VoltageDropDiagnostics]

Thanks for watching!

[@maxwellautoservice_yeg834]

Great job PJ, just got my Autel scope, hope to lean more from you on this Autel, thank you

[@VoltageDropDiagnostics]

Sweet! Do you use it on an autel scope, or on a pc? This was my first time using it on a pc since they updated the software and I was pleasantly surprised.

[@maxwellautoservice_yeg834]

I'm using on both

[@kellyr9388]

Great video as always, reminds me of my Toyota days..

[@VoltageDropDiagnostics]

Who do you work for now?

[@kellyr9388]

@@VoltageDropDiagnostics I have been with Mercedes Benz for the last 4 years. I really liked the product at Toyota, but the ownership and politics at that dealer were too much.

[@stevenkietzke5582]

Nice video Thanks for the information. I've never done a leak down test from BDC. Have to give it a try next time.

[@VoltageDropDiagnostics]

Just remember that the air will be trying to push the engine down, with a lot of force so youre going to need to brace a breaker bar on the crank against something to keep the engine from rolling over.

[@richardcranium5839]

@@VoltageDropDiagnostics and keep your fingers out of the way lol

[@VoltageDropDiagnostics]

richard cranium yes! Because 100 psi of force is more than most people can understand haha

[@felm3283]

Excellent diagnostic!! Master

[@VoltageDropDiagnostics]

Thank you very much!

[@tonymacario1479]

Great video wish you guys where in southern California

[@VoltageDropDiagnostics]

I believe that someone in Texas is trying to bring Brandon down for a class. But don't quote me on that. I also know that there is a training event North of you in Washington State. A huge event actually. You might want to look into that.

[@tracycolorado]

Most excellent video

[@VoltageDropDiagnostics]

Thank you!

[@Ikenik735]

Very good video. I hoop we can see more autel scope videos. Thank you

[@VoltageDropDiagnostics]

I try to mix them up. Sometimes I use the snap on. Sometimes the pico, and sometimes the autel so youll certainly see more videos with the autel.

[@richardcranium5839]

using the leakdown in that way just to confirm that is ok. if you are trying to find worn rings its not. with that kinda milage in rustbelt pa the cost of an engine is more than the car is probably worth unless its a southern car. probably spent that much on the parts cannon.

[@VoltageDropDiagnostics]

You’re saying that finding worn rings with the piston half way up the compression stroke doesn’t work? This car was surprisingly clean. And the engines from the junkyard were cheap, but they had high mileage. The remains were $$$$ 5,000

[@JustinDowDIYcentralhighway]

Good stuff always cool to see another way of doing things 😎🍻👍👍

[@VoltageDropDiagnostics]

Thanks man!

[@bartscave]

Good diagnosis video!

[@VoltageDropDiagnostics]

Thanks Bart!

[@CubasAutomotive]

Whoop! Whoop! The cutest cheerleader ever! Lol! 🙌👈😃👉 Nice to see a new video, feels like it's been a while. Pretty cool. You're not the only one not to have misfire counters work improperly lately also, but I don't count on them anyway. I'm soooooo happy with the latest pulse sensor. It's BEAUTIFUL... but definitely find the two outputs useful.

[@jasonc.4683]

😂😂🤣🤣

[@CubasAutomotive]

I dig the honesty. Selling the engine and the reason behind it. 100% agree after hearing the reasons.

[@VoltageDropDiagnostics]

Yes! I love the pulse sensor that you got from Mike! And I will be the best cheerleader ever! haha

[@jeremyanthony9300]

Hi Cuba

[@CubasAutomotive]

@@jeremyanthony9300 Hello Jeremy! Hope all is well!

[@stevejakobsen2765]

Awsome stuff PJ

[@VoltageDropDiagnostics]

Thanks Steve!

[@EliTheOBDTech]

Good diag Vid PJ.

[@VoltageDropDiagnostics]

Thanks Eli!

[@rookiediagnosticsandrepair5956]

awesome stuff. thanks for sharing!

[@VoltageDropDiagnostics]

Thanks for watching! haha

[@stevepark5504]

An easy way to find cylinder cycle and TDC is to put a toy balloon over the cylinder test hose barb. Then roll the engine. The balloon is very sensitive and will show TDC or BDC. Using 2 of the pressure regulators, like the one you used, in series, with a .062 orifice between them, makes a leakdown tester.

[@VoltageDropDiagnostics]

Thats brilliant!

[@High_Tech_Mountain]

Great video Pj! Just got around to watching it! Top notch content as always! Appreciate your leakdown tool and technique. Great analysis of the waveform and diagnosis. If cylinder 4 compression wasn’t also low would that have lead you to suspect cyl 3 intake valve leaking during compression? As always thanks for sharing brother!

[@VoltageDropDiagnostics]

Thanks Angel! Sorry that I am just getting around to these comments! I have been so busy lately! But to answer your question. Yes. If cylinder 4 wasnt also low I would have suspected a failed intake valve. Good catch on that by the way.

[@thebaldmechanichardatheari1124]

I agree 100 percent for an engine.

[@VoltageDropDiagnostics]

Thanks for watching! And yes, from my experience, one these head gaskets fail, the engine is trashed.

[@stephenmarshall5302]

really good video

[@VoltageDropDiagnostics]

Thank you!

[@VoltageDropDiagnostics]

Check out my amazon affiliate link to help the channel: www.amazon.com/shop/voltagedropdiagnostics

[@georgebonney90]

Great video, thank u👍

[@VoltageDropDiagnostics]

Thanks for watching George!

[@JustinDowDIYcentralhighway]

That’s how I do it. Put my leak down gauges on it roll the engine don’t care where the piston is only where the loss is. 🍻😎🤙

[@hamham4547]

Hey pat very informative video but what I can't understand why there is an intake Pressure spike in the cylinder 3 if the intake valve of the cylinder 4 is open normally the pressure from the cylinder 3 escape to cylinder 4 so no spike in the intake

[@VoltageDropDiagnostics]

So your question is. Why is there a pressure spike, when cylinder 4 is on the intake stroke? My best explanation is that the intake manifold typically under vacuum. But even though cylinder 4 is pulling vacuum, cylinder 3 is pushing pressure. Even if they counteracted themselves perfectly, youd still have a loss of vacuum in the intake until the next cylinder pulled it back into a vacuum state. Does that make sense? Did I answer the question?

[@hamham4547]

@@VoltageDropDiagnostics it does thank you so much

[@drewjohnson265]

#voltagedropdiagnostics thoughts on maxiscope vs. Pico? ...while more affordable, seems the actual Pico software is what sets it apart. Exploring options for a first scope.

[@VoltageDropDiagnostics]

Drew Johnson that’s not a fair question lol. I like the picoscope better. But i do like the autel scope. I especially like the price tag of the autel scope. I feel like the autel is the best bang for your buck in the scope world. The pico is just the best scope.

[@drewjohnson265]

Voltage Drop Diagnostics was watching the video a second time and just caught your comment “everyone’s been asking me to use my Autel”. Missed it before.

[@ignacioorduna176]

I appreciate all your videos you do a great job I have a question I enjoy working on cars I don’t work for a shop I actually work at a restaurant ,can I still attend to Brandon’s class even though I am not a mechanic or have any kind of mechanic certification thank you

[@VoltageDropDiagnostics]

Want to know my opinion about DIYers who want to attend training? lol The majority of professional technicians won't attend training. So if a DIYer does. Is he still a DIYer or is he more professional than a professional? lol Come on down!

[@SuperMarioDiagnostics]

Voltage Drop Diagnostics agreed. Kudos to any DIYr that wants training

[@ignacioorduna176]

Voltage Drop Diagnostics thank you very much for your response I live in columbus Ohio but I will drive up there

[@ignacioorduna176]

Super Mario Diagnostics I have asked you questions as well and you have taken the time to answer I thank you both I actually found out about Brandon’s class because of your channel and seeing it again in this channel definitely I am attending his class thank you

[@VoltageDropDiagnostics]

@@ignacioorduna176 Good! That shouldn't be too far of a drive for you either?

[@billrimmer5596]

Thanks for not using the Pico for those of us with other not so fancy scopes. That Autel did a great job. Was it the injectors disconnected that disabled starting? Because if u disabled spark u wouldn’t get cylinder firing pulse. Igt. Correct?

[@VoltageDropDiagnostics]

Exactly! The PCM wouldnt have seen an IGF signal return and it would have stopped trying to fire the coils most likely. Plus I dont want extra fuel spraying into the cylinder while cranking so I just unplugged the injectors.

[@swathikumarr3597]

Bro I have Toyata Corolla 2007 past few months I have a issues like body vibration and shake and I misfire noise on exhaust

[@1rcracer]

Im having issues with a 09 corolla, cyl 4 mis code, did new coils, plugs still having the miss and surge at stop light, changed up stream o2 and no change.

[@BIONDIEST]

Me too miss fire on 4. Did the spark plugs. The coil on 4. Cleaned the throttle body. Ran fuel injector cleaner. Took it to a mechanic and $114 later they couldn't figure it out said it wasn't mis firing and then the switched injectors 2 & 4. Waiting for the drive cycle but I'm pretty sure the miss fire is still on 4. So I guess the next thing would be a compression check. I wish I didn't just replace a whole bunch of stuff on it a couple months ago. Now that this is happening.

[@swathikumarr3597]

Bro I have Toyata Corolla while driving when I’m move to third gear it’s hesitation include right side door pad also if possible can u suggest and help me please

[@jwoeltje6949]

I would have like to see an in cylinder. I just did one on an S54 M3 Relative compression showed me Adjacent cylinders both low compression. However I did an in cylinder and I didn’t reveal it. So I just would’ve been curious how that one looked.

[@VoltageDropDiagnostics]

My assumption is that i would have had leaning compression towers from the loss of air volume, and my exhaust and intake pockets wouldn't be even. But I'm not sure if I would have been able to make a call from that alone. I should have grabbed one just to see.

[@jonathanratliff4780]

Question please, you had mentioned you frequently see pitting in the cylinder walls of this engine is that what I understood you to say? How does that happen and why? I have a 2009 Corolla 1.8 engine with 250,000 miles and it’s running aces but very curious on that I never heard of that before. Thank you for your answer.

[@VoltageDropDiagnostics]

Not on the cylinder walls. But pitting between cylinders. As far as why. That I’m honestly not sure of. But with your mileage, I’d consider changing the coolant.

[@jonathanratliff4780]

@@VoltageDropDiagnostics Thx so much for reply here in my question. Never heard of this before. I have indeed flushed the cooling system and change the auto trans fluid every 50K miles since odo hit 100K. I also add Lucas Fuel Conditioner with upper cylinder lubricant since the the 100K mark on every fill up. Thx again!

[@ericgolden3285]

Great video Can you pass on my details i am interested in the pulse sensor

[@VoltageDropDiagnostics]

I just messaged him! He will be over shortly to give you contact info.

[@michaelnicholson9092]

Thank you PJ. Eric Golden you can contact me by sending me a message at 360-545-3013 I'll be more then happy to answer your questions and provide you with the information.

[@Waelkhalafabdelrehiem]

sir i would ask you for explaining to me key less entry system on schematic for any Toyota car with explaining the symbol on the schematic and what the letters and numbers means and thanks for sharing

[@VoltageDropDiagnostics]

When I come across and issue with one. Ill gladly make a video for you.

[@TheDisgruntledMechanic]

So how do we sign up for this May 30 class you mention????

[@VoltageDropDiagnostics]

Paul Danner is working out the final details and he will be posting them within a week or 2. He had to find a source to print the books that are OVER 300 pages long!

[@TheDisgruntledMechanic]

@@VoltageDropDiagnostics Thank you for the response,

[@VoltageDropDiagnostics]

www.rosedaletech.org/diagnostics-seminar/?fbclid=IwAR3zb6rtlvh8hmo06ZYkcaVRDRJRtaWK9FkZ12hdBOolEzDmFZBz0xMamk4

[@maldonadolemus]

What I think you should say is the reaseon why the engine is broken too premature. for toyota 210k is not too much. I am pretty sure the engine overheat and the head gasket were blown....But whe question is Why happened that. Skipping oil changes, water systen wast propperly mantain... or the engine were abuse of rev ups, etc,

[@zackarymcclain164]

I spy a Cuba’s automotive sticker on that cabinet. You have quite the collection of stickers. How do you buy one of yours?

[@samwoods5569]

My 09 Corolla Le has a cel that reads cylinder 1 and cylinder 3 ignition coils were malfunctioning. Ignition coil 3 is brand new and has less than a thousand miles on it. One two and four came with the car. Any ideas? Please and thank you.

[@mazdaman7739]

I have an unrelated question about a 2009 Toyota Corolla LE 1.8 auto. Do you think it is safe to do a transmission service on a car with 140,000 miles. Trans service has never been done and fluid is black/red and dirty. Trans seems to shift fine. Thanks

[@VoltageDropDiagnostics]

I wouldn't be too worried about it causing issues. I assume you're just doing a drain and fill? Thats what I recommend, while using Toyota WS fluid

[@mazdaman7739]

@@VoltageDropDiagnostics I'm thinking of just doing drain and fill. I heard filter is more of a strainer so I probably just leave it i guess. At Toyota do you change trans filters or primarily do drain and fills? I think it takes just over 3 litres. Thanks for the response back

[@VoltageDropDiagnostics]

@@mazdaman7739 generally we just do drain and fills

[@DIYDaveOK]

Anything in particular that leads to blown heads on those Corollas, or just one of those things? And what is your overall opinion on the Autel scope?

[@midwestrustwarrior]

I feel it leads back to the coolant. They cause lots of leaks in toyotas.... this car has probably had one water pump by now. By most likely never had more than one coolant change out.

[@VoltageDropDiagnostics]

As far as the autel scope. It isn't as good as a pico scope. But it is close. And it is about 1/4 of the price of a picoscope. So if you want a scope that does 80-90% of what the best scope on the market does, for 25% of the cost. The autel scope is probably the best bang for your buck IMO. As far as the cylinder head failures. I honestly don't know. It's not extremely common considering how many corollas that I see. With how much pitting takes place on the block and head. I think it is a slow gradual failure.

[@DIYDaveOK]

@@VoltageDropDiagnostics I would love to pick up a scope, but there's now way I could drop the coin on a Pico. But that Autel is interesting, as is a little Hantek version I've read mixed reports about. If I had a basic scope that would let me do simple tests, like relative comp, without a ton of $$ invested it would be great for a DIYer like me. Thanks, sir!!

[@VoltageDropDiagnostics]

DIY Dave it used to cost $500 but I’m the description i linked to amazon that is currently selling them for $400 I haven’t used the hantek myself. But i haven’t heard many good things about it. I’d probably buy the autel over the hantek from what i have heard.

[@DIYDaveOK]

@@VoltageDropDiagnostics I think the Autel is probably where I'm heading, esp considering the add'l cost for an attenuator, amp clamp, and a basic set of probes...

[@inhocsigno9151]

But if #3 is on BDC, isn't the Intake valve still open a bit? Or you go just past actual BDC to close the Intake?

[@VoltageDropDiagnostics]

Yeah, i didnt convey that well in the vide but i pinned a comment to better explain it. Thanks!

[@jeremyanthony9300]

How many miles are on that car? I have a 2012 with only 73k on it.

[@VoltageDropDiagnostics]

Jeremy Anthony has about 200k on it.

[@jeremyanthony9300]

@@VoltageDropDiagnostics does that motor comes out the bottom

[@AD-T]

I need a pulse sensor. Also need a in cylinder pressure transducer. And a used pico. Have yet to use any.

[@VoltageDropDiagnostics]

haha! Once you learn to use a pico, it will open up an entirely new way of diagnosing vehicle failures.

[@AD-T]

@@VoltageDropDiagnostics I'm going to that class for sure . Hope you will be there as well and get my pico signed lol.

[@VoltageDropDiagnostics]

Andrew Hinojosa are you on Facebook? The registration for the class was just posted!

[@VoltageDropDiagnostics]

www.rosedaletech.org/diagnostics-seminar/?fbclid=IwAR3zb6rtlvh8hmo06ZYkcaVRDRJRtaWK9FkZ12hdBOolEzDmFZBz0xMamk4

[@AD-T]

@@VoltageDropDiagnostics thanks I'm signing up asap.

[@alexschmidbauer3671]

Great video PJ! I have a question as I’m just getting into pulse sensor and In cylinder testing.. If this vehicle , for example , had an issue with a leaking intake valve on cylinder 3 , we would see an intake pulse higher than the rest on cylinder 1 compression hump because cyl 3 is on the intake stroke? Just trying to think of different scenarios .

[@VoltageDropDiagnostics]

So if you have a bad intake valve. Lets say that it is cracked on cylinder 3. You would have had a hump during the compression stroke of cylinder 3. It would have looked very similar to the waveform that I posted. The reason that I knew that I had a bad head gasket was because my compression for cylinder 4 was also low and I put the pieces to the puzzle together.

[@jeremyanthony9300]

Well 200k is a lot. Would that motor comes out the bottom?

[@VoltageDropDiagnostics]

Jeremy Anthony it can come out the bottom, but it doesn’t need to. It’s pretty easy to pull out of the top.

[@smms5056]

👍👍

[@michaelfrancis3261]

do you know if there will be an online class?

[@VoltageDropDiagnostics]

That I'm not sure of. Not anything soon if there will be.

[@danvceliboys716]

How much would it cost to do an engine replacement on that car my 2009 Corolla has the same problem

[@BIONDIEST]

Idk if I would want another at this point. 187k miles and mine. Switched injectors and it still miss fires on 4 even after dpark plugs and a coil. Pretty sure the engine is screwed. And I just replaced a whole bunch of stuff on it right before. Some bs. Wish I didn't buy a 2009

[@madmike214]

Awesome! Any links to the class?

[@VoltageDropDiagnostics]

Keep and eye out! Paul Danner is working on the finishing touches as far as getting the books produced (the books are over 300 pages) and he will be posting a link to the registration. Ill comment here when he finalizes everything.

[@VoltageDropDiagnostics]

www.rosedaletech.org/diagnostics-seminar/?fbclid=IwAR3zb6rtlvh8hmo06ZYkcaVRDRJRtaWK9FkZ12hdBOolEzDmFZBz0xMamk4

[@Peter-pv8xx]

A couple of years ago my neighbor asked me to look at her 09 Corolla with 230,000 on it, the mil was lit and it had a p0301,,I swapped number one coil with number 2 and the misfire moved , I replaced the coil and it was fine until a month ago when she said it was running bad and the light was on, this time a p0301 and 303 came up, I decided to replace all the coils since they were original except the one I replaced before, it threw a 301 again so i put the newer coil in and I'll see what happens, they were all aftermarket Chinese coils I did because OEM are like 100 a piece, I don't know what else to do, I'm not a pro and she doesn't have a lot of money I think it's just another bad coil.

[@BIONDIEST]

I thought mine had a bad coil or spark plug. I replaced them and it didn't get any better. Now I'm thinking it needs a head gasket because that's the next thing on the list. Or maybe something to do with the timing. It's a huge job and if the block is warped it will be $2200 to replace the straight block and I'm just not sure that's worth it.

[@jdubtech262]

Doesn’t seem very flat rate friendly way to perform a compression test or is this just simply a video to show compressing checking with a scope?... interesting

[@SuperMarioDiagnostics]

Joe Wilson an experienced scope user can have a full diagnosis in less than 15 minutes in just about any vehicle using these methods. Whether there's a plenum covering the coils or not.

[@VoltageDropDiagnostics]

As far as the compression portion of the test. I 100% disagree. Imagine needing to pull an intake on a v6 engine to access the spark plugs, to do a compression test. That can be a time consuming process depending on the engine design. I can have a relative compression test perform in probably 5 minutes without removing a single bolt. I am flat rate, which is why I use a scope. Because it allows me to quickly diagnose failures that I can't see or touch without removing parts to access cylinders. I just used this 4 cylinder as an example because it is what I had at the time. As far as using pulse sensors, and gathering in cylinder waveforms. That CAN be time consuming depending on the failure. Or it can be extremely quick. Just like how mechanics need short sockets AND deep sockets. I feel like this is just another tool for your tool box that can help you in certain situations.

[@jdubtech262]

Voltage Drop Diagnostics so you back probe igt circuit at the ecm for the coils covered by the intake?

[@VoltageDropDiagnostics]

Joe Wilson nope. I backprobe a front coil. If I have a cylinder 3 misfire. And I know that the firing order is 1-2-3-4-5-6 Why can’t I backprobe cylinder 2 that is easy to access, and look at the very next compression stroke of the relative compression waveform?

[@jdubtech262]

And also my comment was just for this particular case where the other shop already replaced all the parts, (also love the fact that they replaced the ecm) you almost already know it’s a mechanical failure

[@BIONDIEST]

Mine has 187k and was running good. First time the check engine came on for the missfire did the spark plug and coil. Moved the injecors around and pretty sure the miss fire didnt move. I'm checking that today. Pretty sure the engine is screwed. What a piece of trash. Cars these days are a joke.

[@charlotteab4606]

I have code po219A.and po304 ....I will change the coil.and inspect the bujia..I will see what happens after....the reason I have 2 coil change in the last two year .the same issues but thie time I don't have the warranty I will suck my self..

[@charlotteab4606]

By the way fuel is bean really but ..

[@kevincampbell8298]

Someone got hosed!!!

[@VoltageDropDiagnostics]

Yeah, unfortunately. I doubt it, but I really hope that the original shop ate the cost of the parts that didn't fix the car.

[@kevincampbell8298]

One can only hope! But sadly it happens. A few of my buddies and I were headed two wards the biz. But after working for a while it became apparent that a lot of places cared about profit. And not much else. I think of the lot of us there is only one that still wrenches for a living. Keep up the great diags!

[@philh9238]

Even a cheap harbor freight vacuum gauge would of seen it.

[@SuperMarioDiagnostics]

Agreed. That shop really dropped the ball. I do like that one could distinguish a head gasket issue from a leaking intake valve in one test though

[@VoltageDropDiagnostics]

Maybe. I honestly didn't try. But I know that a cheap HF compression gauge would have seen this (as long as it has the right adapters for these spark plug holes) or a cheap leak down tester would have seen this. This wasn't a video to show people what they should be doing. But a video to show what they could be doing during the certain failures. It's just another tool for your tool box that can come in handy. Because there are times when leak down tests and compression tests pass, but the engine still has a mechanical problem.

[@philh9238]

@@VoltageDropDiagnostics does the autel scope have a filter? the relative compression test looked noisey

[@VoltageDropDiagnostics]

phil holbrook it does. It doesn’t work as well as the pico filter though. This was unfiltered though.

[@swathikumarr3597]

If possible can u please help me

[@VoltageDropDiagnostics]

Sorry. Without more information, I'm not sure how much that I can actually help.

[@duanedonaldson2262]

I do not use BDC for one simple fact, let's call it valve overlap but that is not the exact proper term. At BDC exhaust stroke the EVO is already happening and at BDC intake stroke IVC has not yet happened. In fact how far open are the valves and how much will they leak, very little. Back to your usage of the overlay chart, different charts have different characteristics, this chart is BAD, the way that you lay it out, you set it at TDC on the left side of the screen, you then dragged the chart to the right to align it with 720* of the next compression stroke but in the process of dragging it to the right, the entire chart moved to the right, honestly for the purposes here, not important, but for the guys who watch your channel and learn from your mistakes, please start the overlay on the right and drag it to the left and it will not move. There are other charts that don't have this characteristic. Thanks for the class on a blown head gasket, with and without nice test equipment, I also only use shop air for a leak-down test. Better to find a leak into the cooling system at TDC, cheers.