Today I met this guy, he is great. He just diagnosed my car evap leak in couple of minutes. Now I have to replace only the evap vent and all lights will go off. Thanks and it was nice meeting you.
I've been using a cheap $40 theatrical smoke maker that puts out a few ponds of pressure with a remote and I made my own adapters to fit many applications. A little knowledge and ingenuity goes a long way.
I guess Schrodinger is a life science HS teacher deeply studies mechanics and is a compable metal worker.he has a adept ability to apply his knowledge to problem solving. Respect
For years I used jack stands and a creeper in my little one man dog and pony show garage. I finally bought a Challenger 10K pound asymmetric twin post lift after which I ceremoniously threw my creeper in the dumpster. Watching you work on that land yacht on the floor makes my heart hurt for you. That being said, kudos to you for making such great videos with that level of adversity. I freely admit I am spoiled and I will never work on another vehicle without it being on a lift. Once I set the lift I’m done with all the work I will do on the floor. Thank you for another great video.
Oh man you are preaching to the choir hahaha!! Yeah I think anyone who watches my videos for any length of time quickly learns how much I hate crawling under cars. about 6 months ago or so I did buy a quickjack 3000TL midrise and while not nearly like yours, it’s a massive massive improvement over jackstands. I just can’t put a 5000lb SUV on it. I do plan to also get a 7000TL which would allow me to lift these bigger trucks and SUV’s. 3-1/2 feet is still such a massive different over jackstands I think I can live with that!!
@@SchrodingersBox for years I had the vision of having a commercial lift so when I built my shop I made the walls 14’ tall. If I didn’t have a place with enough clearance then what you have is the way to go and always get as much lifting capacity as you can afford. Industry standard lifts are usually 7 or 9K but they guy who sold me my lift said he could get me a 10K lift for an extra $100. An offer I couldn’t refuse.
Oh man that’s a great deal!! yeah I have 11 ft ceiling so I think the best I could potentially do is maybe a MaxJax which would let me sit on a rolling stool under the car. I don’t know- we’ll see how it goes but right now I am happy- also that RaceDeck floor makes laying on the floor a hell of a lot better too!!!
Thank you for the compliment. I do get a lot of mention of my clear English enunciation. I think it is appreciated by people who do speak English as first language.
Years ago I bought a similar smoke machine off ebay for about the same price. It works fine, but I wanted a flow meter to quantify the leak. So I bought a simple floating ball flow meter for about ten bucks to add in line. Expensive smoke machines come with pressure meters but I don't have much use for that, and the extra cost is significant. Smoke machines stink, the garage doesn't smell the same for a few days after using it. This was a nice practical demo. I've always thought evap problems were simple, but some of the new systems have a whole lot of extra lines and check balls/vents that can confuse the issue when you apply external pressure. Eric O makes these sound very simple, but I've been humbled.
Good to see you back regularly Dave, reminds of the old days haha. Yeah the system I described is a GM system and for the most part the little ball flow meter would be helpful but I have found other systems can be vastly different. some have pumps to test the system for leaks. others actually calculate the volume of fuel in the tank and the outside temp to calculate what must be the pressure of the vapor in the tank given those conditions. they can any number of one-way valves and complications quite different than this simple system.
"Yeah...that guy". That made me laugh. You have a good approach towards explaining components and systems. That's why I keep coming back. Well, that and your sense of humor.
If you fill up the tank too far(keep going after the auto shut off) you can saturate the canister with liquid......only vapors should go in the canister.I worked at a gas station in my teens in the 70's before I knew this. I wonder how many canisters I ruined by rounding up to the next even dollar so I wouldn't have to mess with coins hahaha
Oh man I should have pointed that out!! yea that’s totally true and in just a couple months ago had exactly that situation. canister was full of gas and destroyed it.
@@brianw8963 Yea the systems were primitive back then,but this was when gas was .50 cents/gallon,so if the pump stopped on$ 9.05 I would round it up to $10.00,almost 2 gallons. There were times I felt like bouncing the car to cram that last few cents in lolololol. This was when a lot of cars had the filler cap behind the license plate so if I spilled over a little the customer never knew it. I found a website called TitleMax and they have a list of gas prices going back to the 30's,and I was suprised to see that adjusted for inflation prices have been at $3.00 or above for most of that time. I started pumping gas on my 16th b-day in 1973 right at the start of the oil crises when prices went from .40 to .60 in a short time.People were shouting at me like I was responsible,and they watched the pumps like a hawk to make sure they got what they paid for. This was way before self-service was even a dream,and I discovered a way to get back at the nasty customers by "hanging" the pump on them.If I had a previous sale for only 1 or 2 bucks I could hang the nozzle back on the pump,but not totally shut the reset lever off. So the next car there would be a dollar or 2 before I started pumping.It took a delicate touch but I did it occasionally and never got caught.
Well, I learn something new every day. I never doubted that your use of "adsorb" was correct, but I never knew what it actually meant - so I did a little looking. Thanks for that little push to get my arse into gear and find out for myself, Matt. Cheers! 👍
"the whole point of being creative is not to think outside of the box, its to realise there is no box" "there is no box?" "then you'll see its not the box that thinks, it is only yourself" had to do it :P
Hi Matt once again great video. I have had numerous issues with my Z28 Camaro and you have helped me understand a number of these problems. Just like that Smog pump issue. I too had the slow fill problem but mine was just a kink in the main filler hose. I had to put a hose clamp around the kink to make the pipe round again All good now. I also noticed that EVAC vent Solinoid, I think is the same solinoid used for the vacuum relief solinoid on my smog pump outlet pipe Graeme .
Great video and instructions. I have a 2016 GMC sierra. I have problems at the pump as well. The gas pump trips instantly if I fill at full speed. If i slow the flow rate down for about 10L it allows the gas to go into tank and after said 10L or so I can use the pump at full speed. Any ideas as to my issue. I live in Canada and I get my truck undercoated for rust protection every year. I've been wondering if the undercoating could be causing an issue with my vent line. Any advice / input is appreciated. Thanks for the diagnostic tutorial.
@@SchrodingersBox I’m not sure I don’t have a voltage meter. I haven’t began my investigation yet. I was just looking for any advice. Where should I start. I was thinking of pulling down the vent tube to see if the end filter is caked in dirt and start there. Otherwise I was going to start unplugging hoses at different points to see if I can pinpoint a blockage. I will be getting into this on the upcoming weekend. Thank you so much for the quick response. Appreciate the help. No engine light on dash. Just issue at the pump as stated in my first post.
Always start with the easiest and most basic things first. That would be a voltage check at the solenoid. You don’t even need a DVOM. I use a $3 test light.
Love the way you explained it. I am experiencing the same issue after getting a fuel system cleaning service done and the auto shop says the service has nothing to do with the fuel pump shut off issue and they will need to take a look at it. Any idea on what they might have messed up?
@@SchrodingersBox They checked the exhaust pipe for the sound coming from underneath, and that is where I suspect they may have thrown things out of place as the heat from underneath is reaching the cabin too. ☹
Good Evening Schrodingers Box My teacher ACCOMPLISHED Schrodingers Box Great tutorial thank you very much for sharing what you know .God bless you ACCOMPLISHED Schrodingers box From Nick Ayivor from London England UK 🇬🇧
I bought one of those! Super sweet little smoke machine. 2009 crown victoria. I ran it from the engine. Smoke was rolling out of my vent tube thats slid up into the frame, and there was a small leak out of the top of my gas tank. Does that mean I have a fule pump gasket thats went bad? Thats the only thing I know of on top of a gas tank.
If you introduce smoke to the disconnected line going from the canister to the solenoid, should we see smoke at the solenoid or see smoke out of the vent line that is up by the gas fill (neck)?
@@SchrodingersBox 2002 Silverado 5.3L When smoke is introduced to the mentioned line, smoke is observed right at the solenoid, not the vent line that’s travels adjacent to the gas fill hose at the gas filler neck. Canister is new but I haven’t tested it yet. Doubt that it's a defective canister. Also wonder if there's an obstruction in the gas fill hose to the tank. The gas neck flapper is intact so not sure what could be causing an obstruction if there was one. I can continuously add approximately 4 gallons of gas before the pump trips, when the gas pump nozzle/handle is in the normal position. If I re-position (angle to one side) the fuel/gas pump handle, I'm able to continuously add approximately 8 gallons of fuel before the pump trips.
I have a code on an 04 Buick rendezvous indicating a small leak. I've replaced the purge valve charcoal canister purge valve and tank pressure sensor! 0 line leaks! Advice🎉 brother??
Start with the basics- what data was indicating the purge valve and tank sensor were bad? Did you apply vacuum to the tank sensor through the purge valve and it failed to activate and the sensor voltage was zero?
When I fill up my tank, the pump occasionally stops. I think it's the canister. I blew into the ports and they seem pretty blocked. The pressure in my gas tank seems to stay at atmosphere pressure, is that normal? should there be pressure in the gas tank? Can there be an issue there or is it due to the canister too? Thanks for the help in advance.
@@SchrodingersBox thank you. I always thought there should be a little pressure but couldn’t find info saying otherwise. I know that the canister has some restrictions in flow so I’m just going to change that for now. I’m also going to do a smoke test of the evap system to check the flow.
What's the approximate cost of replacing an evap canister with your diagnostic time included in your labor charge of this car.? I'm curious because I have a 2005 Hyundai Accent it's doing the same exact thing it takes a while to fill it up because it only can trickle in very slow or the gas pump shuts off
Your issue sounds like a vent valve actually but the cost can vary tremendously depending on the design of the cannister. This particular one was unusually expensive at $680 total because many of the evap components are on the unit itself. Others I’ve done were in the $250 range.
@@SchrodingersBox thanks for replying that fast brother good to see u too posting videos and you will be AWESOME in my book always and thanks for the sharing the knowledge.
Hahaha he amazes me too. you have to watch that video of his. Jeeeeez. 5 million subs too-- luckily they will all keep me busy fixing their cars for years to come lol. “Well I tried SeaFoam but it didn’t work so I changed the plugs and wires” SMH.
@@mrfishbulb7187 The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
Excellent video and training as usual! Question, is the oxygen that the smoke machine is putting in to the fuel vapor system a safety concern or are they relatively safe?
This thinking with no box stuff is quite refreshing and something you just don't find on other channels. Definitely an effective approach to diagnostics for sure! There's also no doubt the canister is blocked with the back pressure, smoke blowing out around the inlet port and no air coming from the outlet port, but would the charcoal inside adsorb the smoke itself like it does hydrocarbon vapors and just pass clean air through? Is the smoke a hydrocarbon? Just curious on what to expect if the canister was not blocked.
Good question. while the charcoal may adsorb some (certainly not at that volume) in my experience it flows through like what you saw with the vent. also- even if the smoke was all absorbed, the air would still be felt and even heard passing through and it did not. but so can tell you for sure on previous times I have smoked an EVAP it just billows right out the vent tube meaning the cannister is not holding the smoke. it’s also a reason when you must close the vent solenoid when checking leaks- so the smoke doesn’t just leave out the vent.
Hello, I got a ford focus 2013, the low beam lights in front and the tail and brake light on the passenger side turns on and then immediately off and wont turn on. Need help please on a procedure how to perform a diagnostic. Thank you so much
I always replace those canisters as the charcoal absorbs the black oily junk from nasty gasoline vapors and moisture, then turn solid. Never needed a smoke machine. A bad switching solenoid usually triggers a code but rarely ever a issue.
Here is another EVAP situation: Saturn 2004 2.2L P0455 code comes on about 200 miles after being cleared, happened two times in a row. Gas cap replaced Purge valve replaced EVAP solenoid replaced 14.4 volts on electrical connectors to purge valve and solenoid when the car is running No problems filling up the car at the pump No smell of fumes or noticeable engine performance issues Short term fuel trim is sometimes as high as 15% when idle , and 25% when at 2000 RPM for thirty seconds and stained at 25% Long term fuel trim is around 4% (I believe that the historic data is being erased when the codes are cleared) O2B1S1 is making a sign wave 0.1V to 0.8V, appears to be working O2B1S2 is around 0.6V mostly with some minor fluctuation, no sign of a bad cat converter Only thing left to try is a smoke machine? ( a hose with a crack?) Could a tank pressure sensor cause this issue? Thank you,
My daughters 2022 Dodge Ram, will not fill up keeps shutting off in about 5 seconds, unless the engine is running then no problem even if you shut the engine off while you are still finning the truck, you can even shut off the nozzle and restart with no problem. Good video what does this sound like? Love you videos and I want to get the e-book you talk about.
So I’m having the same problem. I crawled under the suburban while pumping fuel and unplugged the canister ( the big line) and it still made the pump click off. But once u disconnected the (big line) from the actual tank the one that goes on the top I was able to pump with any problems. What could cause mine to do that? Also I did lower the tank and blew air with a compressor and they aren’t clogged.
Matt, let me "pick your brain" if I might. First, I have done my diagnostics on my own car because of a physical limitation (back) I have trouble getting underneath in tight places. I have a 2012 Hyundai Azera that takes gas just fine... providing the tank is already below half a tank or so. If it is above 1/2, especially 3/4 or greater, it acts just like a very clogged line or canister. With a lower level in the tank it fills just fine. I even tried with the car running to see if the evap solenoid was open and engine vacuum would help. It did not. The car has only a little more than 50k miles. Also, pulling the nozzle part way out to allow some venting doesn't help, either. I found nothing helpful for this using my scan tool. Any suggestions? Thanks.
it is likely still a partially clogged evap that is made worse when tank is filled because the higher fuel level compresses the vapors tighter. the same procedure I showed would have to be used.
@@SchrodingersBox Thanks Matt. I appreciate your response. I enjoy your teaching very much. I've reached the age of retirement... and have retired. I've always worked on my own vehicles and helped friends and family with theirs for decades. I have also always been good at troubleshooting practically anything on or in a car but lacked the knowledge to properly deal with automotive electrical issues regarding sensors and computers. I now have a good variety of test equipment and am working on developing the knowledge to provide advanced diagnostics. You have helped a lot along with a couple other teaching channels. I've been providing some troubleshooting for a few people and it's going quite well so far. The goal: create a better me, keep my mind active and firing those neurons by actually thinking, make enough extra money to pay for all of this electronics, and mostly help others by giving a correct, low-cost diagnosis to those who can't afford to pay a high priced shop an exorbitant fee for changing parts. As you're aware, there are a lot of people who desperately need their vehicles fixed but can barely afford their next meal. I've been there and now hoping to give back. Thanks again for what you do.
Matt, I notice that when I fill up my friends' cars of 20 or fewer years old, I hear an obvious sucking sound. When I fill up my 30 year old OBD1 Protege, I hear no sucking sound. Should I be considering this a potential EVAP problem?
I heard when you use the smoke machine you are pumping air into the tank making for the right condition for it to explode is that true? they say to use nitrogen gas.
I have heard that but you would need some additional catalyst to cause an explosion. just putting air in a fuel tank won’t do it. Others say that the pressure is what does it but you would have to put like 200 PSI to have that happen- the evap would blow long before that.
Yes, I found this very helpful , I have always thought you needed a bi-directional scanner to operate the evap solenoids in the system to diagnose functionality. I can see that is not always true , ,,, another great video , will buy some more merch to say thank you . Have t-shirt , mug and sticker , maybe get that smoke machine .
Glad it helped and to be honest- if I wasn’t filming I most definitely would have used a scantool to command that vent solenoid closed however I know most of my viewers don’t have one so I showed how to identify the circuit and manually activate it. but yeah a scantool would have made it easier for sure. also useful would have been data from the tank pressure sensor from a scantool as well!!
Would have thought that the vapors would come up and out of the filler neck since the filler neck with the gas cap off is a kind of vent was thinking that some gas pumps push alot of fuel through the nozzle and the size of the filler neck sometimes gets overwhelmed by the fast flow causing the gas pump nozzle to trip off.
i have the clicling problem, in a car thats been sitting for years, undriven, could it be rhe spiders ir other rhing like a insect nest or simething? what us the most likely clig?
The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
Do you ever see cases where the evap canister is saturated with fuel because of repeated overfilling of the tank? I know that you're not supposed to continue to fill a tank with gas after the pump clicks off, but I seem to be the only person at the gas station that follows that rule. Everyone else seems to try to force as much gas into the tank as possible. Am I being overly cautious??
Us early 80’s VW Rabbit guys have this issue where gas spews out of the filler neck after 15-20 minutes when the tank is more than half full.due to excessive pressure. Normally it’s a clogged gravity vent valve but what else could it be?
The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
well that’s even crazier than scotty is hahaha!! but I would still triage it at the bottom of the list and I would certainly completely disconnect from the solenoid back when clearing the line out. Also in looking at it in more detail, while tons of vehicles were recalled there was never a case shown where damage to the EVAP or fuel system ever actually resulted. the procedure it turns out was to replace the vent tube with one containing a screen and to replace fuel tank if a blockage was actually found.
Maybe. What diagnoses have you done. Did you measure the voltage at the solenoid? Did you verify solenoid operation ? What happens when you manually activate the solenoid? These are things to be before replacing anything.
This has happened to my wife's vehicle and to at least 10 of our company vehicles Everyone of them has been because people topped off the fuel tank when they were filling it up.
Here's what I don't get: people say that the vent valve solenoid is open by default, when no voltage is applied, and it only closes when the computer sends voltage to it (for creating a vacuum during leak/blockage tests). But in that case I don't understand how the vapor canister is able to "trap the fumes" and release them to the engine via the purge valve (which is closed by default and opens only when voltage is applied)? Because as long as the vent valve is open, all fumes will travel through the charcoal filter and out into the atmosphere, meaning that there's no trapping. And to make matters even worse - your fuel gets continuously evaporated this way. Also, many videos have completely opposite explanations which are 100% conflicting, where one guy says the vent valve is a 1-way street for getting air IN the vapor canister, but never OUT, then another guy says the complete polar opposite (only OUT, never IN), then some others say it's a 2-way street for both IN and OUT. I'm completely lost here...
Yes it’s a function of activated charcoal. It traps the hydrocarbons- maybe think of it like a sponge or a magnet or something that doesn’t need to be closed to trap the hydrocarbons.
@SchrodingersBox But even if the activated charcoal is able to so this sponge-like absorption, won't it eventually get saturated and reach the point where it's "full"? Because I still don't understand how come the rest of the vapors don't simply escape through the vent, basically evaporating your fuel over time. I imagine there is a limit as to how many hydrocarbons it can hold in place, all the "new ones" entering and pusing the "old ones" out the vent as the pressure gradient in the tank continues to emit fumes.
Yes great question man. I like your line of thinking. Yes there is a limit of course to the adsorption of the activated charcoal cannister (the term is adsorption in this case, not absorption because the hydrocarbons bind to the outside of the charcoal as opposed to “soaking” the charcoal inside and out) . But it’s unlikely to be met in typical application because the cannister can hold up to 25 grams of hydrocarbon. As you know vapors weigh almost nothing at all so that’s a LOT of vapor. Remember we are talking about evaporation of gasoline in an almost entirely enclosed system so it’s not like there’s a huge amount of evaporation of gasoline to begin with. Plus with regular driving you are purging the cannister regularly. I imagine at some point it’s possible the fumes could saturate the cannister if the vehicle sat long enough and maybe the temperatures were warm. In that event, yes, the fumes would escape to the atmosphere.
@@SchrodingersBox You are absolutely right, it's "adsorption" because the atoms will undergo adhesion to the surface of the charcoal, but I intentionally used "absorption" as I wasn't sure who'll be reading my comment as time goes on, so I wanted everyone to get what I'm saying and not be confused or correct my spelling 🤗 Btw, I just changed all my 4 injectors tonight and it did not solve my rough idle and random fails to start the engine... Do you think it's possible to have EVAP system problems without throwing any P04xx codes at all and passed emission tests (I just did them today)? I'm thinking of maybe measuring the fuel pressure and air intake pressure before asking people to diagnose the EVAP system (I doubt the guys around here are very aware of how the system works). Cause I'm suspecting possible issues with the fuel pump that would cause both of my issues... I might even replace my ignition coils and spark plugs just to be sure. Or it might be the camshaft sensor. Or the crankshaft sensor... I'm going berserk at the moment...
It’s not likely to have an EVAP issue that causes symptoms and not have a check engine light. EVAP is extremely closely measured. And even if it wasn’t, EVAP is not substantial enough to cause drivability symptoms anyway. Not sure what would make you replace injectors but I would start with a basic fuel trim analysis as my first step so I can get an indication of which system to focus on.
What data showed the canister AND vent valves were bad?? That seems really unlikely. What was the vacuum measurement on the vent valve showing it failed?
Today I met this guy, he is great. He just diagnosed my car evap leak in couple of minutes. Now I have to replace only the evap vent and all lights will go off. Thanks and it was nice meeting you.
Nice to meet you as well!
@SchrodingersBox how much would it cost to do the repairs
My guess would be around $400-$500 up to $1000 if the whole cannister needs replacement.
I've been using a cheap $40 theatrical smoke maker that puts out a few ponds of pressure with a remote and I made my own adapters to fit many applications. A little knowledge and ingenuity goes a long way.
Where might one get one of these smoke generators, such as yours ??
Interested in your build?🤔👊
Sweet!!! 2 videos in 1 week. Best automotive channel on TH-cam!
glad you think so!! yes I have some time through end of year so hoping to churn content more often!!
I guess Schrodinger is a life science HS teacher deeply studies mechanics and is a compable metal worker.he has a adept ability to apply his knowledge to problem solving. Respect
Not science teacher. An actual scientist.
I've watched a lot of videos on evac systems and smoke machines but yours made the most sense . Thanks for sharing.
Good to know!! I do try to be different and actually explain the processes.
@@SchrodingersBox It works very well...the thorough explainations.
For years I used jack stands and a creeper in my little one man dog and pony show garage. I finally bought a Challenger 10K pound asymmetric twin post lift after which I ceremoniously threw my creeper in the dumpster. Watching you work on that land yacht on the floor makes my heart hurt for you. That being said, kudos to you for making such great videos with that level of adversity. I freely admit I am spoiled and I will never work on another vehicle without it being on a lift. Once I set the lift I’m done with all the work I will do on the floor. Thank you for another great video.
Oh man you are preaching to the choir hahaha!! Yeah I think anyone who watches my videos for any length of time quickly learns how much I hate crawling under cars.
about 6 months ago or so I did buy a quickjack 3000TL midrise and while not nearly like yours, it’s a massive massive improvement over jackstands. I just can’t put a 5000lb SUV on it. I do plan to also get a 7000TL which would allow me to lift these bigger trucks and SUV’s. 3-1/2 feet is still such a massive different over jackstands I think I can live with that!!
@@SchrodingersBox for years I had the vision of having a commercial lift so when I built my shop I made the walls 14’ tall. If I didn’t have a place with enough clearance then what you have is the way to go and always get as much lifting capacity as you can afford. Industry standard lifts are usually 7 or 9K but they guy who sold me my lift said he could get me a 10K lift for an extra $100. An offer I couldn’t refuse.
Oh man that’s a great deal!! yeah I have 11 ft ceiling so I think the best I could potentially do is maybe a MaxJax which would let me sit on a rolling stool under the car. I don’t know- we’ll see how it goes but right now I am happy- also that RaceDeck floor makes laying on the floor a hell of a lot better too!!!
Theoretical and practical teaching
With easy English pronunciation language
I am so happy to watch your scientific videos
Thanks dear bro
Thank you for the compliment. I do get a lot of mention of my clear English enunciation. I think it is appreciated by people who do speak English as first language.
Years ago I bought a similar smoke machine off ebay for about the same price. It works fine, but I wanted a flow meter to quantify the leak. So I bought a simple floating ball flow meter for about ten bucks to add in line. Expensive smoke machines come with pressure meters but I don't have much use for that, and the extra cost is significant. Smoke machines stink, the garage doesn't smell the same for a few days after using it. This was a nice practical demo. I've always thought evap problems were simple, but some of the new systems have a whole lot of extra lines and check balls/vents that can confuse the issue when you apply external pressure. Eric O makes these sound very simple, but I've been humbled.
Good to see you back regularly Dave, reminds of the old days haha. Yeah the system I described is a GM system and for the most part the little ball flow meter would be helpful but I have found other systems can be vastly different. some have pumps to test the system for leaks. others actually calculate the volume of fuel in the tank and the outside temp to calculate what must be the pressure of the vapor in the tank given those conditions. they can any number of one-way valves and complications quite different than this simple system.
Oh and yeah- my garage totally stinks now hahaha
"Yeah...that guy". That made me laugh. You have a good approach towards explaining components and systems. That's why I keep coming back. Well, that and your sense of humor.
Always glad to see you here my friend.
Great job diagnosing and explanation about how evap system works ! 👌
Thank you! Cheers!
@@SchrodingersBox Thanks to you for sharing your knowledge with us ✌
An extremely fair deal you gave the customer: free labour in exchange for making a video of the repair. 👍
Thanks, I actually do that a lot. In fact in a very few cases I was so interested in doing a video on the problem that I even paid for the parts too.
@@SchrodingersBox Now that's what I call being curious!
If you fill up the tank too far(keep going after the auto shut off) you can saturate the canister with liquid......only vapors should go in the canister.I worked at a gas station in my teens in the 70's before I knew this.
I wonder how many canisters I ruined by rounding up to the next even dollar so I wouldn't have to mess with coins hahaha
Oh man I should have pointed that out!! yea that’s totally true and in just a couple months ago had exactly that situation. canister was full of gas and destroyed it.
I doubt that You ruined any back in the 70’s.
@@brianw8963 Yea the systems were primitive back then,but this was when gas was .50 cents/gallon,so if the pump stopped on$ 9.05 I would round it up to $10.00,almost 2 gallons.
There were times I felt like bouncing the car to cram that last few cents in lolololol.
This was when a lot of cars had the filler cap behind the license plate so if I spilled over a little the customer never knew it.
I found a website called TitleMax and they have a list of gas prices going back to the 30's,and I was suprised to see that adjusted for inflation prices have been at $3.00 or above for most of that time.
I started pumping gas on my 16th b-day in 1973 right at the start of the oil crises when prices went from .40 to .60 in a short time.People were shouting at me like I was responsible,and they watched the pumps like a hawk to make sure they got what they paid for.
This was way before self-service was even a dream,and I discovered a way to get back at the nasty customers by "hanging" the pump on them.If I had a previous sale for only 1 or 2 bucks I could hang the nozzle back on the pump,but not totally shut the reset lever off.
So the next car there would be a dollar or 2 before I started pumping.It took a delicate touch but I did it occasionally and never got caught.
Just found this channel Enjoyed the information thanks for taking the time.
Very good explanation Thank you, Mr. Scientist!
I about lost it when that spider came out 🤣. I didn't expect him to be right, glad you got it out of there 🕷🕸
HahahHa how come no one else commented on that?? I thought it was brilliant lol
@@SchrodingersBox I guess it was overshadowed by the usefulness of your video being the stand out quality :P
would canned air not be safe to use?
I love your videos. This week alone I learned the problem is usually GROUNDS or spiders. Thanks
Haahahaha. Glad you are paying attention!!!! fricken spiders!!
I love this guy respect from Egypt
Good to hear- I have quite a number of viewers from Egypt!!
Well, I learn something new every day. I never doubted that your use of "adsorb" was correct, but I never knew what it actually meant - so I did a little looking. Thanks for that little push to get my arse into gear and find out for myself, Matt. Cheers! 👍
Hey good to see you back and I am glad you absorbed that tidbit of knowledge lol!
"the whole point of being creative is not to think outside of the box, its to realise there is no box"
"there is no box?"
"then you'll see its not the box that thinks, it is only yourself"
had to do it :P
Hi Matt once again great video. I have had numerous issues with my Z28 Camaro and you have helped me understand a number of these problems. Just like that Smog pump issue. I too had the slow fill problem but mine was just a kink in the main filler hose. I had to put a hose clamp around the kink to make the pipe round again All good now. I also noticed that EVAC vent Solinoid, I think is the same solinoid used for the vacuum relief solinoid on my smog pump outlet pipe
Graeme .
Yes for sure a filler hose problem can cause this as well. often with that issue you will hear the gas gurgling in the filler tube.
Great video and instructions.
I have a 2016 GMC sierra. I have problems at the pump as well. The gas pump trips instantly if I fill at full speed. If i slow the flow rate down for about 10L it allows the gas to go into tank and after said 10L or so I can use the pump at full speed.
Any ideas as to my issue.
I live in Canada and I get my truck undercoated for rust protection every year.
I've been wondering if the undercoating could be causing an issue with my vent line.
Any advice / input is appreciated.
Thanks for the diagnostic tutorial.
what is the voltage at the vent solenoid showing and what happens when you manually purge?
@@SchrodingersBox
I’m not sure I don’t have a voltage meter.
I haven’t began my investigation yet.
I was just looking for any advice.
Where should I start.
I was thinking of pulling down the vent tube to see if the end filter is caked in dirt and start there.
Otherwise I was going to start unplugging hoses at different points to see if I can pinpoint a blockage.
I will be getting into this on the upcoming weekend.
Thank you so much for the quick response. Appreciate the help.
No engine light on dash.
Just issue at the pump as stated in my first post.
Always start with the easiest and most basic things first. That would be a voltage check at the solenoid. You don’t even need a DVOM. I use a $3 test light.
Love the way you explained it. I am experiencing the same issue after getting a fuel system cleaning service done and the auto shop says the service has nothing to do with the fuel pump shut off issue and they will need to take a look at it. Any idea on what they might have messed up?
can’t say without seeing what the technician tested.
@@SchrodingersBox They checked the exhaust pipe for the sound coming from underneath, and that is where I suspect they may have thrown things out of place as the heat from underneath is reaching the cabin too. ☹
Could you also test from tank cap to canister input as well, just to confirm no restrictions in that section?
Absolutely!
Now I gotta buy the autoline universal gas cap . Didn’t think I would need it 👊🏻
Hi, I have a 09 Tahoe and I keep getting a po422 small Evap leak.
I changed the canister, purge valve and gas cap.
Any helpful hints to solve this ?
What data showed the canister, purge valve and gas cap were all faulty? That seems unlikely. What pressure readings indicated this?
Good Evening Schrodingers Box
My teacher
ACCOMPLISHED Schrodingers Box
Great tutorial thank you very much for sharing what you know .God bless you
ACCOMPLISHED Schrodingers box
From Nick Ayivor from London England UK 🇬🇧
You are very welcome as always!!
I bought one of those! Super sweet little smoke machine.
2009 crown victoria. I ran it from the engine. Smoke was rolling out of my vent tube thats slid up into the frame, and there was a small leak out of the top of my gas tank.
Does that mean I have a fule pump gasket thats went bad? Thats the only thing I know of on top of a gas tank.
Could be bad gasket, bad evap valve, bad pressure valve, bad overflow valve….
I can’t believe that you actually still entertain his channel… yeah, I mean THAT channel. 🤣
(START YOUR ENGINES!)
Oh it’s always good to check in and see what the other side is up to.
@@SchrodingersBox I guess... But still! 😂
If you introduce smoke to the disconnected line going from the canister to the solenoid, should we see smoke at the solenoid or see smoke out of the vent line that is up by the gas fill (neck)?
It depends on the design. Most vent solenoid a default open which would put smoke out the vent. Some default closed which would not emit smoke.
@@SchrodingersBox 2002 Silverado 5.3L When smoke is introduced to the mentioned line, smoke is observed right at the solenoid, not the vent line that’s travels adjacent to the gas fill hose at the gas filler neck. Canister is new but I haven’t tested it yet. Doubt that it's a defective canister. Also wonder if there's an obstruction in the gas fill hose to the tank. The gas neck flapper is intact so not sure what could be causing an obstruction if there was one. I can continuously add approximately 4 gallons of gas before the pump trips, when the gas pump nozzle/handle is in the normal position. If I re-position (angle to one side) the fuel/gas pump handle, I'm able to continuously add approximately 8 gallons of fuel before the pump trips.
I have a code on an 04 Buick rendezvous indicating a small leak. I've replaced the purge valve charcoal canister purge valve and tank pressure sensor! 0 line leaks! Advice🎉 brother??
Start with the basics- what data was indicating the purge valve and tank sensor were bad? Did you apply vacuum to the tank sensor through the purge valve and it failed to activate and the sensor voltage was zero?
Thank you professor 👍
When I fill up my tank, the pump occasionally stops. I think it's the canister. I blew into the ports and they seem pretty blocked. The pressure in my gas tank seems to stay at atmosphere pressure, is that normal? should there be pressure in the gas tank? Can there be an issue there or is it due to the canister too? Thanks for the help in advance.
Yes that’s normal. Pressure in the tank will increase when the vent solenoid closes.
@@SchrodingersBox thank you. I always thought there should be a little pressure but couldn’t find info saying otherwise. I know that the canister has some restrictions in flow so I’m just going to change that for now. I’m also going to do a smoke test of the evap system to check the flow.
What's the approximate cost of replacing an evap canister with your diagnostic time included in your labor charge of this car.? I'm curious because I have a 2005 Hyundai Accent it's doing the same exact thing it takes a while to fill it up because it only can trickle in very slow or the gas pump shuts off
Your issue sounds like a vent valve actually but the cost can vary tremendously depending on the design of the cannister. This particular one was unusually expensive at $680 total because many of the evap components are on the unit itself. Others I’ve done were in the $250 range.
Leave ur key turned on while filling up
Great informative video. Do you think i could get the smoke machine from amazon?
Yes you can however you won’t get the 15% off.
@@SchrodingersBox Thank you for the reply. The thing is, I am from Tanzania and I think the site ships only in the US. Am i right?
Great video and explanation! Thank you!
Matt, AWESOME information sharing and love it you start posting some videos this week as always learning from the best. cheeeers
Hey good to see you my friend!! thanks and there will be more videos coming as I have some extra time around the holidays!!
@@SchrodingersBox thanks for replying that fast brother good to see u too posting videos and you will be AWESOME in my book always and thanks for the sharing the knowledge.
Who is "that guy"? Scotty K?
Hahah I don’t want to mention his name but his first name rhymes with Scotty lol
@@SchrodingersBox I KNEW IT! I amaze myself.😁
Hahaha he amazes me too. you have to watch that video of his. Jeeeeez. 5 million subs too-- luckily they will all keep me busy fixing their cars for years to come lol. “Well I tried SeaFoam but it didn’t work so I changed the plugs and wires” SMH.
He shall be known as 'Spiderman' from now on.
@@mrfishbulb7187 The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
Excellent video and training as usual! Question, is the oxygen that the smoke machine is putting in to the fuel vapor system a safety concern or are they relatively safe?
Good question. It’s not an issue at only 1PSI.
This thinking with no box stuff is quite refreshing and something you just don't find on other channels. Definitely an effective approach to diagnostics for sure!
There's also no doubt the canister is blocked with the back pressure, smoke blowing out around the inlet port and no air coming from the outlet port, but would the charcoal inside adsorb the smoke itself like it does hydrocarbon vapors and just pass clean air through? Is the smoke a hydrocarbon? Just curious on what to expect if the canister was not blocked.
Good question. while the charcoal may adsorb some (certainly not at that volume) in my experience it flows through like what you saw with the vent. also- even if the smoke was all absorbed, the air would still be felt and even heard passing through and it did not. but so can tell you for sure on previous times I have smoked an EVAP it just billows right out the vent tube meaning the cannister is not holding the smoke. it’s also a reason when you must close the vent solenoid when checking leaks- so the smoke doesn’t just leave out the vent.
@@SchrodingersBox Thanks for the reply man! Exactly what I needed to know.
Hello, I got a ford focus 2013, the low beam lights in front and the tail and brake light on the passenger side turns on and then immediately off and wont turn on. Need help please on a procedure how to perform a diagnostic. Thank you so much
should be pretty simple- measure the amperage on the circuit to see if there is indication of short to ground as the first step.
That’s very fair of you sir. Just for that and the video I signed up for your channel.
oh wow thanks!!!!
Does the truck have to be on or anything when performing the test?
I always replace those canisters as the charcoal absorbs the black oily junk from nasty gasoline vapors and moisture, then turn solid. Never needed a smoke machine.
A bad switching solenoid usually triggers a code but rarely ever a issue.
back off man, Im a scientist. great ghost busters reference. love it.
Finally someone caught that!!!!!!!
I immediately ordered the smoke machine.......
Good choice!!! I hope you got the newer model- the one with the self contained battery and flow gauge! It’s the only one I use anymore!
Great video!!! Man you scared the shtttt outta me with that spider 😂😂😂😂
Can we purchase the any of the Autoline smoke machines from your website?
You can not purchase from the website. It merely links to Autoline Pro.
@@SchrodingersBox Thanks!
Autoline Pro has a new Ventus smoke machine. Going to give the Ventus a shot.
Yes I have it. It’s AWESOME!!!!
Thanks SB glad you have the whiteboard. It might be the valve from tank to EC :(
Where can I purchase that smoke machine? What's the name? Do you have a link?
Go to www.schrodingersboxQM.com and click the link that pops up.
Here is another EVAP situation:
Saturn 2004 2.2L
P0455 code comes on about 200 miles after being cleared, happened two times in a row.
Gas cap replaced
Purge valve replaced
EVAP solenoid replaced
14.4 volts on electrical connectors to purge valve and solenoid when the car is running
No problems filling up the car at the pump
No smell of fumes or noticeable engine performance issues
Short term fuel trim is sometimes as high as 15% when idle , and 25% when at 2000 RPM for thirty seconds and stained at 25%
Long term fuel trim is around 4% (I believe that the historic data is being erased when the codes are cleared)
O2B1S1 is making a sign wave 0.1V to 0.8V, appears to be working
O2B1S2 is around 0.6V mostly with some minor fluctuation, no sign of a bad cat converter
Only thing left to try is a smoke machine? ( a hose with a crack?)
Could a tank pressure sensor cause this issue?
Thank you,
Is there any evap related data at all? None of that other data seems relevant. Need evap data.
@@SchrodingersBox all I have is a $60 scan tool. Foxwell nt301 I believe it is.
That’s more than sufficient! That’s gives live data. You don’t even need it honestly. Just use a dVOM at half the price.
Never seen an videos on TH-cam showing a dVOM being used for P0455@@SchrodingersBox
My daughters 2022 Dodge Ram, will not fill up keeps shutting off in about 5 seconds, unless the engine is running then no problem even if you shut the engine off while you are still finning the truck, you can even shut off the nozzle and restart with no problem. Good video what does this sound like? Love you videos and I want to get the e-book you talk about.
you have to run the same diagnostics as shown but maybe I would start with the purge valve since it seems to work with engine running.
So I’m having the same problem. I crawled under the suburban while pumping fuel and unplugged the canister ( the big line) and it still made the pump click off. But once u disconnected the (big line) from the actual tank the one that goes on the top I was able to pump with any problems. What could cause mine to do that? Also I did lower the tank and blew air with a compressor and they aren’t clogged.
What happened when you energized the vent and purge solenoids?
Love this channel. Great stuff. 👍
Glad to hear it! I love it too hahaha
Matt, let me "pick your brain" if I might. First, I have done my diagnostics on my own car because of a physical limitation (back) I have trouble getting underneath in tight places.
I have a 2012 Hyundai Azera that takes gas just fine... providing the tank is already below half a tank or so. If it is above 1/2, especially 3/4 or greater, it acts just like a very clogged line or canister. With a lower level in the tank it fills just fine. I even tried with the car running to see if the evap solenoid was open and engine vacuum would help. It did not. The car has only a little more than 50k miles. Also, pulling the nozzle part way out to allow some venting doesn't help, either. I found nothing helpful for this using my scan tool.
Any suggestions? Thanks.
it is likely still a partially clogged evap that is made worse when tank is filled because the higher fuel level compresses the vapors tighter. the same procedure I showed would have to be used.
@@SchrodingersBox Thanks Matt. I appreciate your response.
I enjoy your teaching very much. I've reached the age of retirement... and have retired. I've always worked on my own vehicles and helped friends and family with theirs for decades. I have also always been good at troubleshooting practically anything on or in a car but lacked the knowledge to properly deal with automotive electrical issues regarding sensors and computers. I now have a good variety of test equipment and am working on developing the knowledge to provide advanced diagnostics. You have helped a lot along with a couple other teaching channels. I've been providing some troubleshooting for a few people and it's going quite well so far.
The goal: create a better me, keep my mind active and firing those neurons by actually thinking, make enough extra money to pay for all of this electronics, and mostly help others by giving a correct, low-cost diagnosis to those who can't afford to pay a high priced shop an exorbitant fee for changing parts. As you're aware, there are a lot of people who desperately need their vehicles fixed but can barely afford their next meal. I've been there and now hoping to give back.
Thanks again for what you do.
I use a carboy bung for a beer brewing set up to adapt the smoke machine to the filler neck
Great explanation
Matt, I notice that when I fill up my friends' cars of 20 or fewer years old, I hear an obvious sucking sound. When I fill up my 30 year old OBD1 Protege, I hear no sucking sound. Should I be considering this a potential EVAP problem?
what is the fuel tank pressure sensor voltage?
excellent! Thanks for sharing. The $150 is a good investment
It sure is!
I heard when you use the smoke machine you are pumping air into the tank making for the right condition for it to explode is that true? they say to use nitrogen gas.
I have heard that but you would need some additional catalyst to cause an explosion. just putting air in a fuel tank won’t do it. Others say that the pressure is what does it but you would have to put like 200 PSI to have that happen- the evap would blow long before that.
Would minus evap can still let tank vent? I remove evap can and still cannot fill tank without stopping
It depends on the design. Check the vent solenoid first.
Yes, I found this very helpful , I have always thought you needed a bi-directional scanner to operate the evap solenoids in the system to diagnose functionality. I can see that is not always true , ,,, another great video , will buy some more merch to say thank you . Have t-shirt , mug and sticker , maybe get that smoke machine .
Glad it helped and to be honest- if I wasn’t filming I most definitely would have used a scantool to command that vent solenoid closed however I know most of my viewers don’t have one so I showed how to identify the circuit and manually activate it. but yeah a scantool would have made it easier for sure.
also useful would have been data from the tank pressure sensor from a scantool as well!!
I have a 4Runner with this problem. The venting may be slightly different. Been living with it but now fed up. Canister is very expensive. !!
Would have thought that the vapors would come up and out of the filler neck since the filler neck with the gas cap off is a kind of vent was thinking that some gas pumps push alot of fuel through the nozzle and the size of the filler neck sometimes gets overwhelmed by the fast flow causing the gas pump nozzle to trip off.
i have the clicling problem, in a car thats been sitting for years, undriven, could it be rhe spiders ir other rhing like a insect nest or simething? what us the most likely clig?
I would very simple manually activate the solenoids and check for proper operation.
@@SchrodingersBox sorry my fingers dont work well, so many spelling issues
New canister is too expensive for me, is it worth trying to snag one from a junkyard or is that pointless?
Not at all! Man I used to do that all the time!!!!
The ol' spiders in the vent trick lmao.
The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
the ol banana in the tailpipe trick lmao
This was great! Thanks!
Many thanks your video based on knowledge
Real profushinely work
So nice of you
Do you ever see cases where the evap canister is saturated with fuel because of repeated overfilling of the tank? I know that you're not supposed to continue to fill a tank with gas after the pump clicks off, but I seem to be the only person at the gas station that follows that rule. Everyone else seems to try to force as much gas into the tank as possible. Am I being overly cautious??
Oh my god that is far and away the biggest cause of the issue. never overfill the tank for the exact reason you said!!
the only box is the one that the smoke machine comes in?
Thanks once again for the amazing content Matt! Love the spider coming out of nowhere, entertaining as usual!
Always trying to keep you on your toes!!
We frequently see this issue at UPS.
Us early 80’s VW Rabbit guys have this issue where gas spews out of the filler neck after 15-20 minutes when the tank is more than half full.due to excessive pressure. Normally it’s a clogged gravity vent valve but what else could it be?
any block in the system would cause it. sounds like the vapors are “burping” the gas - later models have preventative for this.
I understand canisters are quite expensive. About how much did that one cost ???
This one was only $180 but I have seen as high as $380
So why we don’t have Evap code in this case
I looked for the smoke machine at the link in the notes, but didn't see it.
it’s at my website www.schrodingersboxqm.com
Good vedio , good break down
Love A1 auto stuff. If dude said he found spider nest he probably did. Sht happens lol
The spiders are called "Yellow sac spiders", and Mazda and Suzuki both had recalls because of them. It's easy to make fun of Scotty, but he's just going off of real articles that are out there... Just a quick search pulls up a CBS News article named "Spider webs in fuel lines prompt Suzuki recall" --- where they also mention the Mazda recall right at the beginning of the article. If you simply search "spider that is attracted to gas fumes", it will promptly list the Yellow sac spider, and talk about the recalls, etc.... cheers
well that’s even crazier than scotty is hahaha!! but I would still triage it at the bottom of the list and I would certainly completely disconnect from the solenoid back when clearing the line out. Also in looking at it in more detail, while tons of vehicles were recalled there was never a case shown where damage to the EVAP or fuel system ever actually resulted. the procedure it turns out was to replace the vent tube with one containing a screen and to replace fuel tank if a blockage was actually found.
What causes the gas to overflow then; on some fill ups the gas comes out runs down the side of the vehicle.
I spray down stubborn connectors with WD with some success
Yeah I also do that but while filming didn’t want it dripping in my face or even worse on the camera lol.
I've had luck with blowing out electrical connections with air and a little pb blaster or wd 40 that usually works
Great tip!
I replaced my silanoid and canister and it still want take gas, maybe the line are stopped up with charcoal pieces
Maybe. What diagnoses have you done. Did you measure the voltage at the solenoid? Did you verify solenoid operation ? What happens when you manually activate the solenoid? These are things to be before replacing anything.
Evap leaks can be very tricky sometimes
Oh for sure for sure!!!! The small leaks are the worse and really a gas “sniffer” might be the only way to find them.
@@SchrodingersBox 😵😵😵
Rust jacked vent valve perhaps? Preliminary guess.
Not in this case but great guess and I test for it because it is a valid variable.
Can this dude be emailed ??
Yes. Schrodingers_box@yahoo.com
@@SchrodingersBox thank you so much !!
This has happened to my wife's vehicle and to at least 10 of our company vehicles Everyone of them has been because people topped off the fuel tank when they were filling it up.
I tried to count how many times smoke machine was said I lost count😂😂😂
Thank you sir
Here's what I don't get: people say that the vent valve solenoid is open by default, when no voltage is applied, and it only closes when the computer sends voltage to it (for creating a vacuum during leak/blockage tests). But in that case I don't understand how the vapor canister is able to "trap the fumes" and release them to the engine via the purge valve (which is closed by default and opens only when voltage is applied)? Because as long as the vent valve is open, all fumes will travel through the charcoal filter and out into the atmosphere, meaning that there's no trapping. And to make matters even worse - your fuel gets continuously evaporated this way. Also, many videos have completely opposite explanations which are 100% conflicting, where one guy says the vent valve is a 1-way street for getting air IN the vapor canister, but never OUT, then another guy says the complete polar opposite (only OUT, never IN), then some others say it's a 2-way street for both IN and OUT. I'm completely lost here...
Yes it’s a function of activated charcoal. It traps the hydrocarbons- maybe think of it like a sponge or a magnet or something that doesn’t need to be closed to trap the hydrocarbons.
@SchrodingersBox But even if the activated charcoal is able to so this sponge-like absorption, won't it eventually get saturated and reach the point where it's "full"? Because I still don't understand how come the rest of the vapors don't simply escape through the vent, basically evaporating your fuel over time. I imagine there is a limit as to how many hydrocarbons it can hold in place, all the "new ones" entering and pusing the "old ones" out the vent as the pressure gradient in the tank continues to emit fumes.
Yes great question man. I like your line of thinking.
Yes there is a limit of course to the adsorption of the activated charcoal cannister (the term is adsorption in this case, not absorption because the hydrocarbons bind to the outside of the charcoal as opposed to “soaking” the charcoal inside and out) . But it’s unlikely to be met in typical application because the cannister can hold up to 25 grams of hydrocarbon. As you know vapors weigh almost nothing at all so that’s a LOT of vapor. Remember we are talking about evaporation of gasoline in an almost entirely enclosed system so it’s not like there’s a huge amount of evaporation of gasoline to begin with. Plus with regular driving you are purging the cannister regularly. I imagine at some point it’s possible the fumes could saturate the cannister if the vehicle sat long enough and maybe the temperatures were warm. In that event, yes, the fumes would escape to the atmosphere.
@@SchrodingersBox You are absolutely right, it's "adsorption" because the atoms will undergo adhesion to the surface of the charcoal, but I intentionally used "absorption" as I wasn't sure who'll be reading my comment as time goes on, so I wanted everyone to get what I'm saying and not be confused or correct my spelling 🤗 Btw, I just changed all my 4 injectors tonight and it did not solve my rough idle and random fails to start the engine... Do you think it's possible to have EVAP system problems without throwing any P04xx codes at all and passed emission tests (I just did them today)? I'm thinking of maybe measuring the fuel pressure and air intake pressure before asking people to diagnose the EVAP system (I doubt the guys around here are very aware of how the system works). Cause I'm suspecting possible issues with the fuel pump that would cause both of my issues... I might even replace my ignition coils and spark plugs just to be sure. Or it might be the camshaft sensor. Or the crankshaft sensor... I'm going berserk at the moment...
It’s not likely to have an EVAP issue that causes symptoms and not have a check engine light. EVAP is extremely closely measured. And even if it wasn’t, EVAP is not substantial enough to cause drivability symptoms anyway.
Not sure what would make you replace injectors but I would start with a basic fuel trim analysis as my first step so I can get an indication of which system to focus on.
Usually evap canister is full of gas because people are trying to squeeze in every once they can get into it
Why do they get stopped up
a very common reason is people overfilling after the nozzle shuts off and gas contaminates the canister.
I swapped out both the charcoal canister and the vent valve and still having the issue 2012 suburban. Gonna give up and just take it to a shop.
What data showed the canister AND vent valves were bad?? That seems really unlikely. What was the vacuum measurement on the vent valve showing it failed?
Working 👍.
yeah I think I just published it before it totally finished processing. should be good now.
Minedoes same I have a volvo 2016😊
Clogged vent line (charcoal beads) from bad charcoal canister was what happened to my tahoe
Usually fails from over filling fuel tank
@@timothyerlenbaugh2908 correct, I had to replace the charcoal canister and drop the tank to clear the vent lines with air
the back door is opened and the front door is closed.
Good job!
Dude! So nice to see you again!! Where the hell have you been??!!
@@SchrodingersBox
i was busy , sometimes i watch a video of yours without commenting its my bad.
thanks for asking Matt!
Dirt dobber mud dobber clogged?
Omg that spider is really really scary 😨😱
The owner can first add gas to a 5 gallon gas can, then add gas to the car, if he really wants to avoid the repair bill 😂