Where the fuck have I been looking? Watching numerous automotive channels specializing in the "removing" of parts. No. Diagnostics are where it's at. Perfect Understanding. You sir, are an amazing teacher.

Wow. Being a mechanical engineer i never saw such a great scientific approach towards the auto field. Red Salute. You are my Guro

Thank you, Sensei. You are helping young people be self reliant & feed their families. Thank you, Brother.

After watching all parts to this video I believe I (you) have figured out my problem with my 91 f150. Thank you!! I followed your directions and I do believe it is the EGR. I added vacuum to the EGR it did not die... just spit and sputter. The upper intake is in need of cleaning very bad too!

Thank you, after cleaning and checking all the egr components I finally sat down and went through your videos for the p0400. Once I understood what everything is supposed to do I came to the conclusion that my egr wasn’t getting vacuum and that was throwing the code. Hoses were good, but not correctly routed, and it was losing vacuum at the bpt. I ended up connecting the hose from egr sensor directly to the egr valve bypassing the bpt. It ran rough but passed the emissions, thank you

I just wanted to say a quick thank you! Even though I understood the purpose in the function of an EGR system, I had time to watch all three of your EGR videos and it helped me discover very good techniques on how to test each individual section. I'm not a professional mechanic but I do try to learn everything about the vehicle that I am driving and right now it's a 95 Yukon TBI 350. Thank you so much for giving me all the information I need instead of just enough to get my butt in trouble. LOL

Just an FYI- Part 3 will be delayed until maybe a couple weeks due to my "real job". And incidentally for the people that give dislikes on this series- how about giving a reason for it so I can improve the videos, or at least let me use the reasons to look into the mindset of the .01% of people that dislike my videos, I am curious to see your rationale and thought processes!!

Thank you for this series! Understanding how the EGR/DPFE/solenoid system works helped me troubleshoot properly, and ultimately find a hole in the vacuum supply line to my vacuum solenoid. This meant that I avoided replacing parts blindly (which would not have fixed my P0401 code).

Thanks for the fresh way of diagnosing problems. I haven't worked on my vehicles in years so I started throwing parts at my truck when I got a egr code. After watching this egr series I understand what the system does and how it works. Bought a vacuum pump and found the problem. Thanks bud

I came here to learn about how the EGR valve work. I am not disappointed. I subscribed and liked this video. Now after 25 minutes I still haven't learned about the electronically controlled EGR valves so I'm going to proceed on to part 2.

I've watched several of your videos now and all I can say is THANK YOU SIR! They remind me of High School auto shop class, but way more informative and concise.

I did have the EGR code show up when I had Auto Zone check the Check engine light. Fortunately I do have a bit of automotive knowledge and wanted to research the problem myself before paying for the EGR valve. That's when I found your video. It was quite helpful as I was able to clean my entire kitchen while listening to your video at the same time, you do have a tendency to be a little long in the wind, all good. Anywho, it turned out to be a dry rotted vacuum line, hard to find but got it. Not only did it fix the code but it also fixed my A/C blowing thru the defroster vents too. Thank you for the info. Peace out.

Always the guy I enjoy watching and learning that I'm that 2% but humble enough to learn more than I knew before.

Jus read a load of howto vids on how to remove EGR valve. BUT I now understand what I have to do. Brilliant explanation.Thanks a mill.

Dude you are a hell of professor, I have learnt a lot with you, thanks for your efforts and dedication.

Was researching engines for a swap. Just picked up an 05 Malibu with the DOHC 2.2 Ecotech. 3 firing cylinders and have lost all acceleration. Seeking food for thought I have found your channel. Liked and subscribed. When I get my code and next steps to take will update. Until then soaking up your learnings! Thanks 😁

Excellent video. I was one of those 98%'ers who took my car in to Autozone to get the check engine light read and get quoted for parts. I'm glad that I held off and decided to do some research as to what the actual problem was because I ended up coming across this video. Thank you for the time and effort you put into this. It helped a ton.

I love you! I can't yet figure out what is wrong with my precious car but you are teaching me so much! I have spent two years on the internet trying to diagnose my car. I know it's something a mechanic COULD do for more money than I have (NONE!) and I have learned the basics but you explain it in such a great way even my non mechanical brain can understand it. Plus, I get your humor and that is awesome for me! I wish you lived by me so you could tell me what is wrong with my car. I would trust you to fix it for sure! Otherwise, I live in the sticks and my car has been going downhill since paying 1500.00 for a valve cover gasket replacement and a tune-up. Yea. I hate mechanics. I have a Mitsubishi Eclipse 3.0L V6. The spark plugs are $100.00 alone. I wouldn't have minded paying the price but my car has never, ever been the same. So, I don't drive it much, but you are the GUY who makes me understand what no other guy I know has ever been able to, so THANK YOU!

recently bought my first obd2 scanner with no idea what many terms meant such as short and longterm fuel trim...thanks to schrodingers box i now know this ...love the vids very educational

"Swaptrons" lol. They do make up 98% for sure. Much more fun to swap parts than to sit down, read, research, then fix ONCE (sarcasm here). I'd rather spend 2 hrs reading, learning, and planning than 2 hrs in the sun, cursing and getting all worked up changing things I don't need to.

I just started watching your videos. You have really supplied us with a thorough understanding of the EGR systems. Thank you for all your hard work. I have a minor suggestion. When I use your drawing, I have added numbers adjacent to each failure point in the system, you talk about. I then use my numbers in my notes, so I can refer back to the original drawing for each point in the system where the failures typically occur. This way I can tie the failure points directly to the drawing. It is helping me keep track of each failure you are providing to us. Great job with these. I have subscribed to all your videos. I am looking forward to watching every one of them. You are helping me a lot with my troubleshooting.Thanks

Wrong profession? Good for us . Glad to be here. Very informative, i have to be plain rude to the 98% often just to stop them from destroying fine engineering designs.

Very informative. Thank you. I too always want to know not only how to replace parts but also their function (purpose) and how to test properly. Thank you very much!

Mr perfect has never messed up once... bet his love life is 💯

Matt, I love the swagger you display in the introductions to your videos. No one else begins his or her videos by pandering to 2% of potential subscribers and tells the remaining 98% to stop watching. It is refreshing to say the least. Just don't move to a smaller state like Delaware or Rhode Island or the masses might be able to find you.

Thank you so much for the information. I fixed my P0401 code by replacing the short L shaped Vacuum hose easily seen near the upper front of the engine. It had rotted out. In addition, it fixed the problem with the HVAC mixer doors that were not operating properly for years. This bad hose also feeds the vacuum line going to that part underneath the dash. A "TWOFER"...

I just ordered 02 sensor ,was about to order new egr sensor and valve when I learned about cleaning the ports which get clogged , so I'm gonna try to check into that and clean em , so I reckon I was part of the 98% of schmucks that throw parts at it , I'll admit it . This man has so many haters it's ridiculous, haters gonna hate its what they do! It's when you don't have haters that you need to worry and take a step back and see what's going on.

Great Series Matt...Thank you! Sorry if I'm late to the party! I...no, my wife has... a 2011 Suburu Outback which has begun to stall after engine warmup whenever it returns to idle. Starts right back up and continues running smoothly as long as the engine speed is kept at or above 950 rpm. Drop below that and it stalls again immediately...no stumbling or roughness, dies immediately. Cleaning the maf, throttle body and doing the Suburu idle relearn procedure has made not difference (But it was time to clean them anyways...). I have a bidrectional scanner with both an idle and egr test and command option for the outback. Keep the idle at or above 950 and it idles all day long.... Fuel trims are good...short term around 0, long term around 3. MAF, MAP, Throttle actuation all respond as expected with the scanner. The only thing which caught my eye is that I noticed when sending commands via the scantool to change the step count on the electronic egr, the desired step is displayed, but the actual never changes off zero...so I'm going to do some more testing on that....but I'm a little miffed because with something out of whack enough to cause the engine to die, I have no codes being thrown at all...for anything. .. According to the pcm and scantool initial tests, everthing is just fine with the engine...could there be something wrong with the egr system bad enough to kill the engine but not have a code thrown...for something? While scanning and futzing around with it over the last few days it must have stalled out at least 20 times already.....seems like it should have a code for something by now....? Any thoughts or suggestions would be greately appreciated....I'm puzzled...

I SAW thousands of videos on car maintenence this the first one i download to start making a learning video list

Thanks for this it gave me the knowledge to check my system out. Found multiple cracked lines that I could find after listening to this. THANKS!

I can't think you enough for taking the time to make this video series. I wish my college professors could have explained shit with the clarity and simplicity that you have done. This video has saved me a lot of time and money. Keep up the good work brutha!

The angry cat logo on a t shirt and pet food bowl would be totally awesome! MEE-OWW!😂 Im currently battling low-flow/ clogged ports. I think I will try oil gallery brushes. Thanks Matt! I always learn things here. Thanks for sharing your time.

I happened to stumble across your videos on TPS, as I wanted to find a way to check my TPS performance before blindingly replacing it. You did exercise my patience for the first few minutes, but it was well worth it. I really enjoy your approach to these matters, and appreciate what you do. I know how to use a DVM and oscilloscope, so the understanding you impart is vey welcome in these parts of the Bay Area. Thanks for sharing!!

Without doubt my favorite channel on youtube. I maintain my own cars and and enjoy your channel when I want a full understainding of these systems. Keep up the good work.

Just wanted to drop by and say that eventhough my car runs perfectly fine I still love your scientific approach to problem solving! Keep the great videos coming! Thank you sir. 😎 🙋‍♂️

I love your videos. Your making technicians and not just part changers.

G'day Matt, many thanks for stopping me being one of the 98%!!! Turns out I have a dud DPFE. I like your style. Keep up the great work!

I just wanted to say thanks! I used your videos on understanding fuel trims (and a few more) to correctly diagnose and fix my 2004 ford expedition when five different reputable mechanics couldn't figure out what the problem was (fortunately I didn't take their advice to replace the fuel pump and various other components). Turns out the component connecting to my egr valve was plugged with carbon (the air intake manifold?). I took it off, cleaned off the carbon build up, vacuumed out the egr valve and things are back to normal. In the process I tested quite a few components and determined that they all worked correctly... components that various mechanics noted I needed to replace. Anywise, much appreciated and I look forward to learning more on your channel. Thanks!

Thanks for the good infol on the egr system, my only question is what about excessive egr flow? I using the knowledge aquired from your video are thinking that the valve is cruded up and not closing completely. Tomorrow i take a look and see if i can check this theory out. Wouldnt mind your input.

23:21 - it should be opposite - *riching effect on O2 graph, despite engine sees no extra fuel* (EGR gases contains almost no O2 or very little O2 in comparison with fresh air), so more EGR gases in intake manifold = less fresh air with O2 in intake manifold -> almost all O2 available will be used in next combustion cycles -> no O2 (or very little) remains will be thrown to exhaust -> so O2 sensors sees almost no oxygen in exhaust gases -> riching effect in scan tool O2 sensor graph. This is a reason, why engine is killed (effectively suffocated), when EGR is stuck open, because there will be excess of exhaust gases and almost no O2 in intake manifold. PS: I like Your approach to car diagnostics very much, so I have watching all Yours videos from "bumper to bumper" and still learning something new :-) (I'm not mechanic nor parts changer, but car diag hobbyist. I'm very appreciated to Your work! Thanks!)

Sorry knew I was thinking of something else too haha you were mentioning the different types of failures they can have from carbon build up, failed EGR solenoids, broken hoses etc.. don't forget to mention the classic restricted exhaust. This will really screw with DPFE Style EGR's and the Chrysler's that use a "back pressure transducer" in conjunction with a vacuum solenoid. Dodge used those in the late 90's early 00's a lot. There I think that is every thing that was on my mind. Going to watch part II now!

Hey Matt! I have been watching a lot of your videos in order to gain more diagnostic knowledge and understanding of auto computer systems and sensors. I have learned a lot but I am stumped with the data I am getting on a 2000 Honda accord EX 6 cylinder. It will start and run fine when cold. After driving around for about 30-45 minutes with stopping for a few minutes as 2 or 3 places, at the last place I stopped, I came out and the car started but was extremely rough running and would not respond to throttle when pressed to the floor and usually died. I kept trying to start and get it running and after about 10 minutes of trying it started and was rough but throttle response was a little better and shortly it was able to get up in RPM and I was able to drive it home. I hooked up my basic scan tool, AL 539b and the codes I have are EGR Valve insufficient lift (two different codes), which is a codes that I have had for years and code P01399, a random misfire code. That is all the codes I have. The STFT is rather high at idle about +14% when the engine is cold and running good. The long term FT is at 0 (zero) and stays at zero no matter if the engine is running good or is misfiring and rough, or accelerating the engine, no change always zero. When the engine is hot, the STFT is as high as +47% and comes down with more throttle. When the engine is cold again it starts fine and runs good again. I am thinking a fuel problem and not a spark issue because I am not getting any other misfire codes. I was getting oil in a few spark plug tubes, on really bad and was probably affecting the ignition coil. I have replaced all the spark Plug tube seals and cleaned the oil from the ignition coils. Just prior to this. But this same exact problem occurred before I changed the seals and cleaned the coils. I did not have the scan tool before, so I don't know all the data except the symptoms were exactly the same as now. Can you give me a direction to go with this data? It does not seem to fit any of the things from your videos. exactly or close enough for me , with my inexperience to decide a direction. I was thinking of starting with fuel pressure, however, the intermittent nature from cold to hot seems to lean away from fuel pressure.

This guy is the best! This is super useful and going to help me greatly!

Hi friend.... You are a master!...very easy and enjoyable lessons.... i am just knowing about this new section .... Congratulations..... Keep doing this way!!!!

It's fun changing parts out for a beginner like me at age 66, it's the cost of my self education , the advanced course will be learning how to diagnose problems. PS - I have a 1989 c1500 305 V8 . I wish I was a smart ad you, maybe in my next life 😂

Excellent video, thanks. Answered my question of how the computer knows. Understanding solves all problems.....

This is fantastic! What a refreshing idea - actually educating a technology so most everyone can understand. I'd call this the Kahn Academy of Automotive. But it's more! Rather than just a marker board w/ voice over, we get to see parts working and, of course, your entertaining commentary. Thank you & keep up the great work!

i appreciate these videos and the effort you put into explaining this all. thank you!!

thank you for the advises it really helps increase my ability on diagnosing. shout out from pilippines

i just love this channel

👏👏👏 bravo ! U solve my problem with my kia grand carnival crdi

Nice video, well explained but one question i have from your video and all the other vids ive watched say that recycling the exhaust gases back into the intake manifold results in cooler temps.... arent exhaust gases really hot? How could that result in cooler engine temps? Is it because it turns to vapor form? Thanks

221k subs now bro. Nice job being honest and helpful

hey pal,great great job you are doing for humanity !! I am also a Dr like yourself,ways to justify your dissatisfaction to others ,to win your arguments against opponents or please everyone is notoriously idiosyncratic ,best is do what you do best which is teaching and eliminate all others..i.e complaints and we still honor you for your valuable help. Thank you very very much :)

Thank you so much for the lesson, very wise words help enhance the drawing,

Bro I’m in great way to explain it thank you🎉🎉🎉

Awesome explanation! Nothing worse than talking to an arrogant pr**k that boasts about how to fix something but cannot tell you the why part. Truly enjoy your videos. Thank you for devoting your time to this.

I recently pulled the EGR on my '98 Trans Am and put block off plates on. Still have to get it to the tuner so I can get rid of my check engine light haha. Your Trans Am looks clean!

I love this guy keep up the good work

I'm listening on my phone and my kids keep hearing duty cycle and laughing abnoxiously. Lmao🤣.as always great video, he's such a great teacher.

Thank you for talking so clearly. I did not miss a word and english is not my language.

Ever wanted to know why exhaust gasses get put in the intake? Find out from my friend here. (A comment for those who can see that I shared the video.) Matt when you said, "Swaptrons." You really had me laughing LOL Makes me want to see another transformers film. :) Thanks again for another excellent add to your diagnostic series.

I may be wrong but around minute 14 on where you talk about the solenoid venting to atmosphere my understanding is that this is to allow the diaphragm to return to closed position when the solenoid is de-energized

You're VERY interesting and explain things fully-- better than the 3 min. 'quick change' vids

Good video thanks, I have a question, would I get a low egr flow detected if the CAT was choked as I'm getting the low flow code and very poor performance.

Hi there, I have watched many of your videos even though I am not a mechanic or advanced do it your selfer. I am the guy that takes a shot in the dark and changes parts thereby wasting my hard earned money and much time. The reason I do this is because I do not know what the hell I am doing when it comes to diagnosis. Of course I changed the egr, etc. If you live on or near Long Island I would love to bring my vehicle to you to fix. I know you would figure it out and actually fix it unlike my efforts. And thanks for the cool vids, Jimmy

Hey Matt, great video and thanks for enlightening the curious 2% of us. I do have a question about the EGR: since is letting in exhaust gasses into the intake manifold, shouldn't its operation result in rich condition rather than lean condition? I'm thinking that the exhaust gasses will reduce the proportion of oxyen in the air fuel mixture and logically that should lead to a rich condition. So what am I missing?

Hey Matt, -First of all, great explanation and descriptions (and drawings) ! -Second... see what you think of this, your welcome to share it or refer to it if it helps in your laying this out, I know your style and I know you will like it ;) kzfaq.info/get/bejne/ha-gZ9yIs5elqWw.html -Third and last as I was making dinner and listening to you talk about EGR "sensing" I will call it, a few things came to mind. You mentioned the decrease in MAP, on vacuum style EGR's and a potentiometer on linear EGR's It brought to mind that some vacuum controlled EGR also have a pontetiometer on them too. Think of the early 90's Fords with the big white "TPS" bolted to the top of the EGR. I also thought of some of the Toyota systems I have worked on with a EGR Temp sensor to tell the PCM "hey I'm open" and then remember we have the DPFE (Delta Pressure Feedback EGR) system that Ford also likes to employ. I also remember working on some mazda's that had there own separate "boost sensor" just for the EGR system. I was also trying to remember but I think it was GM back in the day when they first started using electronic EGR's they had one that had 3 pintles all with different size orifices and it would just open and close any combination of them at 100% duty cycle to obtain a certain amount of flow. At any rate put my brain in flash back mode. Hope you get a chance to look at that video!

Really interesting and helped sort my cars problem, which after doing the suction test on her and turned out it actually was the egr valve. Thanks

I’ve replaced my VCV my EGR valve. I don’t know if it’s my air intake manifold being clogged my solenoid. I never even heard of a solenoid until now. I have a 2000 Toyota Camry LE 4ycl and bought a chilton instruction manual and I am in need of further education

i am 68 old an just startedt to watch this program. i am an old tool & die maker and retired. this is a hob, for me .i jusr bought a jagura, the masair flow code

Love the humor, not to mention the education!

Subscribed. Everyone should.

This man is very intelligent. Just by his verbiage I can see.

Your the second best site on the internet, with porn being number 1 of course.

very thorough and informative

dealing with two vehicles with EGR issues. Buick and Ford Whew. Gonna have to watch this a few times.

Matt excellent information and explanation about the EGR system, your videos each day are better so stop being changers parts and thank you very much for the subtitules =) Greetings from Spain.

weck, I was that 98% people until I watched your video. I changed egr value but light still on. So i am trying to learn how to diagnose the whole egr system instead of spending money on unncessary stuff. How do I find out problem is that i realized my lights sometimes on and sometime off. So I think it probably just wire connnection issue. and the only electric connector is locate at solenoid. So i took off the connector and blowed it. crazy the code was gone!

EGR - keeping throttle body cleaning spray manufacturers in business since 1972...

Very insightful, thank you.. Why put people down though? Seriously, so very well explained step by step..

Very good video. I have now too day change parts on a Smart 451 Diesel. New egr valve, solenoid, tro body and map sensor. And drives like New. Thanks

You must be a motivation speaker

Cited this video in my Toyota EGR component testing video... awesome content!!!

Thanks ,very educative

I want to thank thank you now. I wish I had found your videos sooner but oh well. Thank you

Hi Matt, thank you for your great tuitions and don't worry about your drawings because they explain everything just fine. One thing that you did not mention is the DPFE sensor and how we can check that. I got a P0401 code a few months ago and someone told me to replace my DPFE sensor which I did as they are only a few bucks and the problem when away, but now I am getting the P0401 code again (but this time I will follow your video and check everything) but could it have failed again and how do we check them. Thanks.

I'm glad I ran right into this I was seriously looking for this

Thanks and well done. I have a problem with a Peugeot 1.6 HDI which has black smoke during accelleration. Turbo changed and also EGR. Planning to get a specialist to look at it........I have seem some excellent vid's on the 3D mapping. My instinct is either the turbo control ( not enough air ) or the EGR controller ( too much recirc of exhaust gas ). Any general ideas for me to think about ???............Other than the black smoke during accelleration the car starts and drives perfectly. P.s. There is an error code (may not be related) ref; emissions. Which I think is the O2 sensor.

A bit late here but if I connect the vaccum pump to the line that goes to the Q end of the modulator and apply vaccuum then we should get a stall if the solenoid is open, correct?

I would like to know the symptoms of a bad EGR or whatever we are looking at. I have a van with over a half million miles and it blows lots of soot out the tail pipe, staining the concrete or whatever, and I have replaced the fuel pressure regulator, which seemed to help for a little while, but it's back to blowing lots of soot out the pipe. I replaced the MAP sensor, Throttle Position sensor too, and although it runs much smoother and with more power now, it still throws lots of black soot out the pipe. So I'm still trying to learn what I can to see if I can track down the problem. I don't like taking it to shops. One shop charged me $1500 dollars (which included towing) and all the problem was, was worn out spark plugs which I replaced myself afterwards. That was $1500 for nothing, except they replaced 3 parts. So far, I think I am doing about as good as they did.

Thank you for your videos, I especially like Diagnosis and Understanding Series. To learn how things work and what they are made for, hope to see more videos in that format. Regards from Armenia.

1) Only when there is oxygen left in the exhaust gasses the lean condition will occur when opening the egr valve: you would expect no or the very minimum amount of oxygen in the exhaust (which is used to determine the optimal stoi point). 2) can you explain how the in cylinder temp is lowered by this design using an egr valve?

The best channel on you tube.

I always enjoy and learned so much watching your videos.

Yes thanks. I was starting to think I was the only one with an expensive parts car 😀

Matt, Love the series. I apologize in advance for not being able to find my reference or resource of my following question/input. I recall reading that an advanced use of the EGR system is to also fill the combustion chamber with inert gas in order to reduce the volume of the chamber during times of reduced performance requirements. Essentially, making a big engine smaller because we don't need the power at that time. We can then "pad" the chamber with "something else" (less compressible) and provide less fuel (keeping our stoich though). Have you come across any information that suggests this theory in conjunction with or in lieu of "just for emissions". I have searched and was unable to find this information again. I was looking forward to sharing it with you as it was a really interesting article. For some reason though, I think I read it in a FSM for a GM product (I know it's vague, but it might spark your interest or memory). Disclaimer, I know it doesn't physically reduce the volume of the chamber, was just an example of how it would work). I love your videos and hope you keep it up. 2 percent for life!

This video is great. Perfect and best explanation.

You can't please everyone,just a fact of life. Who knows you may ruffled the feathers of a couple of rice burners.. They likes outweigh the dis likes. I hit like once more to offset it a little more.. Great content well explained theory of operation..

Great video! I've for a 1999 Tacoma throwing a P0402 (Excessive) code. I applied vacuum to the EGR valve and it started to kill the engine so I am pretty sure the EGR valve is ok. I wanted the video and can't seem to figure out how to determine Excessive flow.