Intake Pressure Waveform Anomalies

[@ikusha84]

Brilliant analysis! At first I thought it could be due to VVT or faulty EGR valve. I'm glad I found your channel, thank you.

[@billnelson269]

14 year shop owner, very good diag, and great explanation, well done.

[@DTEAuto]

Thank you, I'm glad it made sense. Thanks for watching

[@scottschantz2553]

Pretty awesome that both of these cars came in with the same problem and you were able to compare side by side. Your ability to read between the lines enabled you to conclude that both cars had the same issue but were displayed slightly different. Great learning experience. Great job man! Thanks.

[@DTEAuto]

Yes it took a minute to figure out why one looked the way it did and the other not, Thank you for watching

[@quidelicia1]

Really nice! The exhaust pipe represents a resistance to the air flow, and if you have a hole, witch represent less air flow resistance, it´s like electricity: it gonna flow the easiest way, disturbing the cylinder burnt gases exhaust process. While entering "clean" air to the cylinder, the exhaust and admission valves are opened together for a brief moment to help to push away the burnt gases. So, cyl 1 is sending pressure to the 3 through the exhaust pipe.

[@ikusha84]

That's why I like Toyota's D4S system with both port and direct injection 🤗 No overheating and no carbon buildup on valves.

[@jimbo427vette]

Another educational lesson on detail of wave form analysis, I would have went the fail of intake valve. This is one of those freak things that happen in out shop where its a bunch of starters then tune ups then alternators all coming in one after the other. Thanks for taking the time to share your findings.

[@eacherenkeka]

What a great diagnostic video Sadel! I need to watch it again because I was driving but you say same owner, same cylinder misfire, different cars but the best thing about it same excellent tech! I was hoping to see the exhaust waveform in the first car with the smallest hole! A guess would have look normal with the bad cylinder but with flutter around the peak! Thanks for sharing brother! Take car!

[@DTEAuto]

Thank you, and yes unfortunately I didn't get an exhaust capture of the first one. Thanks for watching

[@ssrbob]

That was a super interesting case study and really fortunate you had two identical failures on the same engine back to back. It goes to show there are a lot of dynamic things going on with flow in the cylinder. I think a good visual way to explain it would be imagine sucking on a straw with a little pinhole in it, you would still be able to suck a good amount of fluid through the straw. Now if you imagine the straw had a 1/8 inch hole in it, you would not be able to pull much fluid if any through the straw because of the large leak. It does take lots of practice with this stuff to really understand what's going on.

[@DTEAuto]

Thats a good analogy example, thanks for that.... I know you are well versed in this subject so hopefully others can understand better with your statement. Thanks for watching

[@amarghani]

I have to watch it again to digest it, but it is an excellent and interesting video.

[@DTEAuto]

Glad to hear it was interesting, and I'm the same way, I have to watch over and over to fully grasp things, but it helps me learn it well. Thank you for watching

[@mrblonde2013]

Just thinking about the first engine, there are 2 more ways the compression can 'escape', this being a gdi engine, a leaking injector seal or a incorrectly installed sparkplug. Not likely, but something to consider. Cheers.

[@DTEAuto]

Good points to make, Thank you for watching

[@himeedajew]

Great information! Just came across same situation as you. I didn't go as far as you. Just did pressure transducer in crank case to check bottom end make sure that was ok and checked problematic cylinder with borescope and seen burnt valve. Can I ask as a mechanic what was your recommended fix? Just change the burnt valve and lap it? Do a complete valve job? Or send off the head to a machine shop? And why not put pressure transducer on exhaust side for 1st vehicle...the one with "good" intake trace? Thanks

[@DTEAuto]

On this one I repaired both in house by replacing the valve, lapping it and new valve seal. Both were for a car lot. And I believe I did use it in the exhaust just didn't film it. If this is a personal vehicle you might consider doing more than one valve. Thank you for watching

[@himeedajew]

@@DTEAuto Thanks for the response. Ahhh yeah so I imagine the car lot would want to go the cheapest route. I recommended to my customer to just get a rebuilt head. which they did

[@pantelis241]

Very nice diagnosis, I am just curious where did you connected your pressure transducer to the crankcase ? PCV valve maybe ?

[@DTEAuto]

for crankcase measurements I usually tap into the dip stick tube or the oil fill cap

[@TrevAutoTech]

You did say you could see an anomaly in both exhaust traces on both vehicles ?? Great video! Thanks

[@DTEAuto]

I only showed the one exhaust trace which was on the second vehicle, and yes the anomaly could be seen there as well. Thank you for watching

[@jharrison6557]

When you see a spike in the intake waveform when a dead cylinders relative compression waveform is at TDC, does that indicate a valve sealing issue with the dead cylinder?

[@DTEAuto]

it is very likely so, you would just have to double check to verify.

[@clueless6559]

Great video thanks for going to the trouble of doing this for us , one question was there a difference in intake valve build up between them , cheers again .

[@DTEAuto]

Glad you enjoyed! And no there was not much of a big difference on the intake build up on either engine. I certainly was glad to be able to capture this one and share it. Thank you for watching

[@robertmobileman8304]

good video , would of been good to see you using a exhaust pulse sensor aswell, what was the cause of this no. 3 burning of intake valve ? cheers

[@DTEAuto]

I did use a sensor in the exhaust, but it was an inches of water not a pulse sensor, that was what I explain towards the end. As far as the cause of the burning of the valve I'm not sure. Thank you for watching

[@automotiveservicetraining9653]

Great video, thanks for posting.

[@rafaelgarcia-xk7eu]

I understand your using a -30 vacuum sensor. I purchased the ats sensor also, along with the their tailpipe sensor and pressure pro 5v box. However I'm having trouble "zeroing" them on my pico. Can't get them below @ 1 volt. Did you have any such problems? Any tips?

[@DTEAuto]

Hey, I actually don't use the ats for intake or exhaust. I only own the 300psi ats one that I will sometime use for incyl. Other than that I have my own that I use, as far as the zeroing, you most likely would have to contact ats and have them explain how to do so. But honestly, from my experience on the exhaust, you won't need to zero it out, you are just wanting to see how the pattern comes out. And on intake, you also might not need to zero it out, as for intake patterns you are looking to see the breathing activity occur or not occur or rise in psi and so forth, not necessarily looking at the spec levels at what it is doing it at. Hope this helps,

[@rafaelgarcia-xk7eu]

Thanks for replying. I did contact ats, the gentleman I talked to said he would get back to me, but I haven’t heard yet. I realize the signal shape is what matters rather than it’s voltage, however when used with companion sensors not needing the 5v box, it takes a little more setup to get all signals on screen.

[@gfbemc0256]

Why not use the pico wps500 & eliminate the problem?

[@JoelAutomotiveInaction]

I am trying to digest 😃 ,thanks

[@DTEAuto]

Thanks for watching Joel

[@mayowaodus6310]

Sadel am back again. Nice diagnosis right there. But did you care to find out why those two Kia had same issue(exhaust valve breakage) .Are they of the same engine type. Could you kindly reply with me with the type of pressure transducer used. Thanks

[@DTEAuto]

As far as the cause I'm not totally sure, the sensor I used was a -30 psi absolute transducer. Thank you for watching

[@roderickzappareynolds2316]

Great video!

[@DTEAuto]

Glad you enjoyed it

[@ebrahimsadeghi5883]

Great info

[@DTEAuto]

Thanks for watching!

[@nickayivor8432]

What do you call INTELLECTUAL AND PRODIGY AND ACCOMPLISHED AND KNOWLEDGEABLE the answer is D-Tech Engineering My teacher SUBSTANTIAL D-Tech Engineering Sharing what you know thank you very much helpful information video Take care and have a great Weekend with all your family around you ScannerDanner told me about your channel From Nick Ayivor from London England UK 🇬🇧

[@djosbun]

That’s just bizarre, Sadel. Is the second car also a 2013 or if not does it have the same engine? I’d love to see someone find a good running Kia (with the same engine) and try to do a detailed temperature measurement across the cylinder head. I’m betting the #3 cylinder is running hotter and causing the valve failure. Well done, brother!

[@DTEAuto]

I cant remember what year the second one was, but I sure wasn't expecting all of what I found

[@james9152]

To avoid any assumpions, u cud have done a cylinder leak down test and listened for the leakage at the tail pipe. Just saying😉

[@DTEAuto]

yes but that wouldn't teach you why the intake waveform between the 2 were different.

[@mike-yp1uk]

Great video but why not pressure test the exhaust or put shop air into the cylinder as a leak test. Teslong makes an awesome boroscope which is awesome to see inside a cylinder an extra 5 min. Makes you absolutely on target. Good video

[@DTEAuto]

you can certainly do that for sure, but you would have to do other test to lead you to that point, i.e. like a relative compression at least. As far as for me on this one, I went this far to teach myself as to why the same faulted issue caused 2 different waveform patterns so that I could better my experience and knowledge and also because I like this kind of stuff. Thank you for watching.

[@mrblonde2013]

"Mike...." you are missing the point buddy. These non invasive tests are done to avoid having to pull a sparkplug/coil/intake manifold etc. The idea is to get familiar using these tests on an engine that has easy access and one could then follow up with a traditional test, like a leakdown test, to back up your results. So that when you get an engine that has no access to the sparkplugs you have a good method to test. The idea is to be more efficient.

[@NEMOJA]

Why wouldn't you scope the pressure on the bad cylinder? You would've seen the bad exhaust valve right away

[@DTEAuto]

In cylinder pressure shows you if there is a leak and displays lower pressure readings because of it. The test won't show the actual place of leak, just the presence of a leak, that's why you have to test around the in cylinder to see where the pressures are not acting correctly to pinpoint the source. A broke piston ring/lower end problem will display a similar waveform, both create a leak, so further testing would need done to find the leak area. Plus, a lot of what I put out is to teach and show others how you can perform test to find problems, not displaying the silver bullet fixes.

[@NEMOJA]

The psi cylinder test is the number 1 test to do. You teach them how to read a cylinder waveform they would've found that cylinder never pulls vacuum with that huge exhaust leak. Also the compression waveform of that cylinder would prolly be very obvious

[@train4905]

Wow awsome😊

[@DTEAuto]

Thank you for watching

[@secretsquirrel9722]

Brilliant teaching Sadel! Unlike women, the scope doesn't lie = size does matter, hahahaha! Excuse me if I missed it, did you cover what sensors you used for each pressure waveform? Your map sensor hook ups? Wondering how the intake waveforms would differentiate with just a pulse sensor?

[@DTEAuto]

I use -30psi absolute pressure transducer and in the exhaust an inches of water sensor, and to be honest I don't know how it would have appeared with a pulse sensor, I don't use them, but I would almost venture to say might not have seen it the same way

[@secretsquirrel9722]

@@DTEAuto thanks for replying man! Which "inches of water" do you use? Zero stress of you don't get back to this. I know most use the ATS unit. I tried a while back to find a budget option in the correct range and sample rate. All I really came up with was a 5v refrigerant manometer.

[@DTEAuto]

you can use a gm fuel tank pressure sensor

[@secretsquirrel9722]

@@DTEAuto MASSIVE tip! Thanks so much for sharing.

[@secretsquirrel9722]

@@DTEAuto side question = What are you using as your 5V ref. A supply box with batteries and regulator (lm7805)? Or 12v battery clamps and a regulator? I see may use a dedicated 9v battery box but using 12v from the cat battery seems so much more simple, straight foward and compact in application.

[@sivucit]

Hi, can I come to conclusion with below facts. 1. Relative compression test using scope will identify the cylinder in question. 2. Any pulse that stand out in intake or exhaust wave form confirm it is TOP END PROBLEM. do incylinder pressure wave form to reconfirm it or leak down test on the cylinder that was identified in relative compression test 3. Any pulse in dip stick confirm it is bottom end. reconfirm with cylinder identified in realtive compression using leak down or incylinder test. Net -NET intake and exhaust wave form along with realtive compression wave form identify top end work, dip stick wavve form identify bottom end work. then drill down more with leak down to reconfirm. Can i also assume that if there is a misfire because of coil or spark plug, i wont see anything stand out on intakke, exhaust or dipstick wave form ?..

[@DTEAuto]

All of that sounds pretty correct, sounds like you are starting to understand it lots 👍 Just play and practice lots with known good cars to get more familiar with it in person.

[@DirtyWorm12]

I just had a 2016 kia Sorento GDI turbo with a cylinder 3 misfire, I had the same waveforms as the second kia. 😂

[@DTEAuto]

😱👍