In this video I show how you can use intake and exhaust pressure waveforms to help determine cause of a misfire. I try to breakdown the results of the waveform that were captured specifically on this 2018 Chevy Equinox that had a P0304.
I don't speak english ..I understand. Maybe a 35 % of that language..but to me i got it 100% what are you try to show us.. Dios te bendiga ..y no habia visto tu canal hasta q hiciste la colaboracion con joel automotive in action..pero tienes una gran canal
I'm glad to hear that it helped you! If you are curious for more crazy pressure signal info, watch the Mercedes misfire video that I did, you will pick up good info from that one as well, as always thank you for watching!
I've never seen pulse analysis better than this and now what I see on mine makes sense. Thank you. I think that a cylinder leak down test would be more proof but this seems good enough
thanks, yes this was a very in-depth testing, and the only thing about the leak down testing that I have heard is that it doesn't always show the fault or leak, it sometimes can mask it and help "seal" the valve against the seat, the scope testing gets to "see" it more in an actual running condition
At the first i thank u for this information U are the man that i have been search for it last for 3 month searching for some one like u Big thanks for details and how to think God bless you
Great video from the beginning to the end brother! Very well explained! I always heard about leaning towers and deep expansion pockets meaning an engine mechanical problem but never explained the way you did! Marvelous! I used pulse sensor but now I know I will get at least three evap pressure sensors and practice more because I know there are more videos coming and still a lot to learn from you! Thank you brother!
One word, awesome ! , very concise explanation. I never encountered a similar approach, keep going sir and thank you for sharing. We learn a lot a lot from you, and as you said to one of your followers, one should learn learn learn and practice to understand Fully what's going on. Thanks again.
ACCOMPLISHED D-Tech Engineering My teacher Impressive Tutorial great video thank you very much for sharing what you know God bless you and all your family around you ACCOMPLISHED D-Tech Engineering From Nick Ayivor from London England UK 🇬🇧
I enjoyed your video. I would suggest that you invert your probes as necessary in order to keep the pressure / vacuum directions the same between signals.
Awesome video brother! Would have been cool if you had disconnected the Pcv from the manifold and re did the cranking waveform. Thanks for sharing as always!
Glenn, I absolutely thought about this same exact thing as I was watching the video during editing ! Nice to see you thinking outside the box! Thank you for watching!
Hey Dava, thank you for that , and yes I will continue to share more like these.... but if you haven't yet, check out my other videos I have posted, they have just as much detailed info. Thank you for watching
Great demonstration. Thanks for taking the time. I think your explanation was very clear and elaborated very well. I did have one question which has to do with the exhaust and crank case pressure waveforms. You stated that you like to use pressure transducer‘s instead of pulse sensors, and on the intake That shows vacuum pulling down but on the exhaust wave form in the crankcase wave form it’s the opposite direction. When looking at the waveform I would think that was more confusing because pressure is going down instead of up. Is that indicative of the sensor or do you have the waveform inverted intentionally For some reason? I think to keep it clearer in my mind I would invert the waveform if that was the way the sensor displayed pressure and vacuum. just so pressure went up. I’m looking forward to your response. Thanks again for all the detailed explanations.
Hey, yes you are actually correct about how the direction of travel doesn't match how we would "expect" the vacuum and pressure to travel. And yes it is due to the type of sensor and how it outputs its voltage based off pressure inputs. The sensitive one that I use in the exhaust and crankcase is an inches of water sensor and displays vacuum upwards and positive pressure downwards. That video was early on before I realized I was confusing people with my explanations when it came to that sensors readings. For me then and even still now I have learned and gotten used to being comfortable with how it outputs its voltage and I can easily correlate the pressures with it, but if I use it now a days and have to explain it on video I will invert the trace so it doesn't confuse people as much. Engine pressures and pulses have been one of my main interests as far as learning and now explaining, I try to convey it in a way that others that are trying to learn can understand it. Hopefully it comes out that way, and I actually have a good one coming out hopefully this weekend (finishing editing it and trying to cut it down some because it's close to an hour long but I don't want to sacrifice information) where I deal with a misfire, and I find the root cause with incyl and intake pressure pluses. Keep an eye out if this is a subject you like. Hope this helps with your questions and thank you for watching as always.
Just a quick question. If you were able to pull the oil cap off while cranking do you think that the intake vacuum anomaly would go away. That would be an interesting proof of concept and also testament to the sensitivity of your sensor. As a thirty year mechanic it is mind blowing the levels of diagnostics that are available now without having to take anything apart. It sure beats watching the needle on a vacuum gauge bounce around and making guesses at what the failed part was. I appreciate all the time and effort you put into your videos. Keep up the great work. DowntownTodd
I had actually thought about something similar , but only as I was going over and editing the video. And yes, I believe with the scope you can test so much with minimal disassembly it's so crazy what can be done and seen. Thank you for watching
I actually use some that I had made for me to my specs, the plan is to have them made in large quantities to be able to sell. But they are all absolute type style, I do not use pulse sensors (like for intake or exhaust)
Hey Steve, its hard to explain via here....but the pattern for #4 shows two towers and a deep expansion pocket. The deep vacuum you see is form during the expansion stroke just before the exhaust valve opens. Expansion pockets will always form during cranking (and running) but when compared to a known good other cylinder in the same engine, if the vacuum level is too much different and lower , it means that during the compression stroke just before the expansion stroke, some mass/volume/psi leaked and so when the piston now travels downward after compressing and traveling upwards, it now doesn't have the same volume/mass it started the upward stroke with and so it goes into a vacuum sooner and since the piston still travels the same distance then the vacuum that was reached sooner in the stroke last longer in that faulted leaking cylinder and so it is able to reach a deeper vacuum level just before the exhaust valve opens. So if you have one where the tower peaks isn't as high as known goods and the expansion pocket is deep, it means you have a mechanical leaking issue at hand. hope this helps some and thank you for watching
I did not use a pulse sensor (like first look) I used an absolute style that tells actual psi , which is just like how the pico one would do, and yes of course you can use the pico one for this testing
Hey, I actually don't use pulse sensors.... I never really did, they to me are just too confusing to try deciphering the waveform they create. I used a -30psi transducer for intake and an inches of water absolute sensor in the exhaust.
How to you setup your pulse sensor to catch the intake and exhaust waveforms? Do you put the sensor in the dipstick? Sorry im knew to all this and trying to learn
No need to apologize, it's great that you are trying to learn. I actually don't use pulse sensors, I use transducers which read a little bit differently. But the concept is the same, If im looking at intake I will usually pick the purge port going into the manifold, for crankcase readings I will use either the dipstick tube or the oil cap port, for exhaust I simply put it at the tailpipe
I just found your channel and was wondering if it would be easy to identify which exhaust peak corresponds to a particular cylinder by disabling spark/ignition of say cylinder #4. Once we've observed the change in the waveform, if any, would it be a matter of plugging the firing order to tell which peaks match the each cylinder.
Yes, the exhaust can be used to monitor for misfire, there definitely will be a change in the waveform when monitor the exhaust. I did a video showing an example of this, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2gC14-SdElk.html
A homemade inches of water sensor I made, it's just as sensitive as a pulse sensor but it's an absolute style so it gives me actual current pressure state, not just change
Just did a diag for this same issue today. Stuck a camera down there, you could see the edge of the prison burnt and bad scoring on the cylinder walls. This is a common failure. These are horrible engines.
A -30 transducer.... I don't like the pulse sensors for that reason and don't use them. If you are in a pinch you can try to use the engines MAP sensor and tap into the signal line. Depending on the quality and speed of the sensor , and some scope trace cleaning, it might give you good enough waveform of actual intake pulls. Hope this helps Bill
