'09 Corolla misfire diagnosis 

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.

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.

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

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.

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

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!

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

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 ❤️

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

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

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!

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.

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

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.

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❤

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 👍

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 👍👍

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

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

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 RU-vid legends haha and that class is more than worth it

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

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

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

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

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.

Great Diagnostic Process !! Thanks for sharing !

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

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

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

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

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

Excellent diagnostic!! Master

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.

Awsome stuff PJ

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

Good diagnosis video!

Most excellent video

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

Good diag Vid PJ.

Great video wish you guys where in southern California

awesome stuff. thanks for sharing!

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

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

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!

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.

really good video

I agree 100 percent for an engine.

Great video, thank u👍

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

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

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.

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.

#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.

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,

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.

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

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. 🍻😎🤙

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

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?

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

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

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

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.

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

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

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

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?

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

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

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 .

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?

do you know if there will be an online class?

👍👍

Awesome! Any links to the class?

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.

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..

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

If possible can u please help me

Someone got hosed!!!

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

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.

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.