EVAP-Evaporative Emissions System Operation, Testing, & Diagnostics Beyond the Leak (P0442, P0455)

hey welcome everyone into the wells tech garage for this week's training class it looks like you guys are all here the comments are rolling in already so awesome it's great to see you guys here happy june it's already june 1st crazy right time flies especially when you have a newborn at home here's here's my little guy i got him uh obviously behind the wheel right away right i mean you got to do that start him out as a car guy when when he's young so uh there's just a shot of a shot of my little guy for you guys all right so today as many of you already know we are going to be covering evaporative emissions we're going to go over the operation diagnosing the system testing it and we're going to get a little bit beyond the leak today because there's a ton of youtube videos out there and stuff already on leak checking system so i want to go a little bit beyond that and do something hopefully that maybe you guys don't think to do or or don't do every day um and we're gonna go start to finish through the evap system today okay so let's start with the tech question this is gonna be that t-shirt giveaway or hat giveaway question um i believe it was you warren that was asking when this would be coming well here it is here's your shot to win either a super awesome wells tech hat or t-shirt in gray blue or black so answer this correctly and you will be a winner so a vehicle is brought into the shop after failing emissions check engine lights on with a code p0442 evap small leak these following tests were performed there's a service based scan tool test done that test failed it is failing it has a leak smoke machine was hooked up to the service port under the hood no smoke was found and the smoke machine was also used to pressurize the system and then watch the gauge the gauge is maintaining pressure so it is not showing a leak with pressure what is the most likely cause of this problem okay i'm not going to give you guys any a b c or d this time i want to know what you guys think is the most likely cause email your answer to me and my email address was right there with the question otherwise it is in the link below or on the screen there um in the description below the video you will also find it you have until the end of today which is june 1st 2017 you have till the end of the day to get me that email out with your answer to the question if you're correct i'd be happy to send you either a hat or a t-shirt also for those of you guys that watch every month you'll know that today is the last day of the wells tech survey you have until i believe i'm closing it at four o'clock central time today today will be the last day so if you haven't already completed our survey that link is also down below in the description fill that out for your chance to win one of these tech shirts with uh your name on it instead of mine i'd be happy to uh send that one out to whoever randomly wins that i will be announcing the winner during the next class in july um one other thing i want to talk about really quick before i get into evap is auto mechanica chicago it is something that is personally i've never been but i've heard it's a great training event for technicians if you guys haven't already signed up for it i recommend doing it i will be there every single day i'm going to training classes i will be an attendee not a trainer um so i'm just gonna be there soaking up knowledge from other trainers and stuff out in the industry so again if you haven't already signed up do that soon if you'd like to go um and then hopefully we can uh we can beat up there and uh snap some pictures together okay all right let's get into evap what exactly is evap or evaporative emissions well it is a system that is intended to not allow our fuel vapors to escape out in the atmosphere the epa decided a long time ago that we can't be allowing these fuel vapors to to be vented externally so we put evap systems on our cars it is also one of the top contributors to our check engine light on almost every make and model check engine light complaints evap ranks up there near the top for complaints and again the goal of the evap system is excuse me to prevent those fuel vapors and honestly guys i feel like this system is confused or misunderstood on many of our modern cars and i'm hoping by the end of today you guys will have a better grasp a better understanding because evap really should be a money maker for your shop um yeah i'll just leave it at that um also you know you got to think if there are almost a billion cars on the road today imagine what it would be like if we didn't have any emissions controls because these vapors that could possibly vent out in our atmosphere are creators of smog pollution and just all around bad a bad time for for planet earth so we like evap systems we want them on our cars and we want them functioning all right so the evap system now just like every other system on a car there's really no mandate on what components you use to do the job the job is to create something to trap those vapers and then some way to get rid of the vapors now every manufacturer seems to do it a little bit differently today we're going to go over this standard evap purge seal system the system that's been around for basically since the beginning of evap okay we're going to go over this system in the next couple months we're going to get into the split seal system that's used on asian vehicles we're going to get into the chrysler nvld or esim systems we're going to talk leak detection pumps vacuum pump systems and the dmtl systems that you see on some asian vehicles so over the next few months we will be getting into these um but today again we're just gonna be talking the standard purge seal system okay so what exactly does that mean again basically it's been around forever and it's got quite a few components here but we all pretty much have been used to dealing with those for a long time so we got our fuel tank our fuel filler neck and then some sort of sealed gas cap or more so on modern vehicles some sort of filler pipe door and i'm talking forward on this with that capless system um this vehicle that's sitting here behind me is a 2010 escape you can see this is what that capless system is it's the easy fuel system there's no cap on this system whatsoever this little door right here this is essentially our gas cap okay this is there's a seal inside of here this is sealing our system okay because our system is not able to vent to the atmosphere okay and then we have a purge valve or purge solenoid something like this it's going to be connected to intake manifold vacuum on one side and then back to through some hoses back to the canister on the other side this should be normally closed it's typically going to be mounted under the hood somewhere with either a hose or like this one directly connected to the manifold um i was in a training class one time where this was referred to as the front door of the system and i like that analogy because we have a front door we have a back door and everything in between should be sealed up so the back door on the system would be the vent solenoid this would be like a remote mounted vent solenoid you would find this with a hose attached to it connected somewhere back to the canister this is going to hang out maybe in a fender well maybe up above the transfer case on a chevy truck um location on this is usually under the vehicle somewhere near the canister now this is also a vent solenoid i'll bring it up so you guys can see a little closer this is also a vent solenoid this is the solenoid that is on the escape that's sitting right here this is a 2010 escape and this vent solenoid mounts directly into the side of the canister so it's kind of a unique setup um i got pictures of that as well so here's the canister and the escape it's got a nice little shield covering it it sits just forward to the gas tank and i took the bolts down you can see we got some wire running here this goes to a connector right here which runs the wire over to our vent solenoid which is on the other side right here and then we also have some hoses connecting this thing to the gas tank and the filler neck as we as i take it off and throw it on the bench you can see here's that connector i talked about running the wiring around and to the vent solenoid right here from here here's a close-up shot of the vent and you can see that thing is embedded into the into the canister this vent is probably like what maybe two inches long or so and that goes into the canister now of course you're not able to pull the vent off with this black plastic shield around here you would have to remove the canister from its um nope let's go back here you would have to remove the come on remove the canister from this black plastic shielding there's just some bolts holding it on the bottom in order to get the vent solenoid out but that is where it goes right on the canister so it's kind of a unique vent design on this vehicle so just wanted to bring that up because we're going to be playing around with that in a little bit all right so we have a vent solenoid going to be normally open our vents basically is exactly what it sounds like it is a vent for the system which is connected to our vapor canister this guy here has activated charcoal inside the goal of this is to store fuel vapors the activated charcoal kind of absorbs those vapors and holds onto them until the engine is ready to burn them off until the purge solenoid is open and the engine is ready to burn them so our canister is holding these vapors our vent solenoid is connected to it somewhere through a hose or directly in the side the the charcoal in here is able to kind of filter those vapors out and only allow fresh air to breathe in and out of this vent therefore we're not actually allowing any fuel vapors out in the atmosphere but our system is able to breathe efficiently because if it couldn't how do you feel how do you fill it with fuel right you can't have a fuel tank full of fuel and air and try and force more fuel in there without having the air able to go somewhere right or the fuel vapor is able to go somewhere so that is why we have a vented system but it's important to note that because we have a vented system it doesn't mean we're venting fuel vapors we don't have a vented gas cap or anything like that we're venting only fresh air okay from there we have a fuel tank pressure sensor this is the brains behind the operation this is monitoring the pressure inside of the tank inside the lines inside of the system for leaks i guess this is what we're using to check for leaks and check for system integrity the computer watches the pressure on this which operates very similar to a map sensor three wire sensor and it's going to watch this over time to check for leaks i'm going to get into leaks in a little bit here some vehicles like on our test vehicle that was for the question we have a test port that's mounted under the hood it's got that little green cap schrader valve inside similar to uh like on your fuel line that one is for evap it's typically going to be mounted on the purge solenoid line you would see a green cap on there and that is where that's going to be mounted and then of course we have hoses and lines connecting all of this together so i actually have a setup over here that i put together as a demonstration for you guys so you guys can kind of see it off of the vehicle because if we look at it on the vehicle here it's um kind of you know feet 10 plus feet of hose in between components under the hood components under the vehicle near the fuel tank it's kind of hard to explain how the system functions without being able to see it again you guys know i'm a very visual person so i built this so that hopefully i would hopefully i would be able to help you guys to understand exactly how the system works so with that being said here's our fuel tank with fuel in it and um some friends that apparently don't stand upright our rubber duckies are drowning in there but there's our fuel tank we got a fuel pump assembly in here these are all gm parts this is actually the setup of a early 2000s chevy cavalier if you guys are familiar with working on those that's where all of these parts came from filler neck gas cap sealed up purge solenoid which is connected to a hose remember this is gonna be under under the hood connected to a hose back to our canister and then we have another hose coming off the canister this is the one that's going back to our fuel tank this is the one when the vapors build up inside of the tank they'll travel up to the canister and then we also have our vent solenoid here which is going to allow the system to breathe that fresh air so i also have a smoke machine hooked up here and i'm going to go ahead and power this thing up maybe cycle my power source here and i should be able to show you guys i'm gonna apply smoke to this so that this is gonna be just like vapors on the system okay so we're gonna start to see our vapors building up in the tank right so you guys can see that yeah all right our vapors are filling up inside the tank now ignore that this is a smoke machine just pretend that these are vapors inside of here they're going to build up in here all the time those vapors have to have somewhere to go obviously we can't just allow them to come out of our gas cap you know the epa says it's bad so we have to seal up our gas cap so the vapors are going to travel up through this big hose back to our canister where canisters job is again to um filter with that activated charcoal and store those vapors until our purge solenoid is open and the engine is able to burn now right now our vent solenoid is open and you can kind of see if i hold it over by the black you can see that it is able to there is smoke coming out of it okay now the reason why there's smoke coming out of it is because the charcoal inside of here is not actually absorbing the molecules of the smoke because how how good would a smoke test do on an engine or on a vehicle if the charcoal canister absorbed all your smoke before it would even get up to the purge solenoid or something like that so our vent solenoid is gonna show the smoke coming out of it it is venting it but again this would not be fuel vapors this would just be fresh air so i'm gonna go ahead i'm gonna close up that vent solenoid and as many of you know testing vents you get that click sound so there we go that's closed up and remember our purge solenoid is going to be normally closed so right now the system is going to pressurize we're going to build up a bunch of pressure in here because i have the vent closed you can see our needle here is dropping our ball in here is dropping and what i'm going to actually do now is i'm going to open the purge just like the engine were to be purging vapors out of this thing okay so we open the purge i don't know if you guys could hear that pressure release or i can see this there we go you can see that so now this would be just like the engine drawing vacuum on the system drawing the vapors out of our tank out of our canister and into the engine to be burned okay all right we'll go ahead and shut this off i'm gonna go ahead and pop this off so we can kind of evacuate out the tank and i'm gonna head back over this way so basically that is the most basic and standard of evap systems functioning i also have some um operation animations for you guys here i'm going to go ahead and play this this is only a couple seconds but basically it's going to operate just like i said so we have this animation loading we have our fuel tank down here fuel tank pressure sensors in there monitoring the pressure or vacuum in our tank those vapors are building and they're traveling up this hose into our canister all right our canister's job again is to filter those vapors because we can't allow those vapors out in the atmosphere so we're filtering and they're going to travel up through this hose and through our normally open vent solenoid into the atmosphere so for building pressure in here we're able to vent that pressure into the atmosphere after it's filtered after it's filtered and it goes up into the atmosphere okay so this is this i know it says idle mode here this isn't engine idle this is like the system in idle this is the system key off engine off this is the system when it's not purging this is the system when it's not testing this is the system just kind of hanging out doing what it's supposed to do but at some point that charcoal canister becomes saturated those fuel vapors overcome the capacity of the charcoal canister potentially and they need to go somewhere we have to get rid of those vapors that's when we open up that purge solenoid so then we would have something that looks like this so again our vapors are flowing up from the fuel tank into our canister and at some point the computer decides okay it's time to turn on the purge solenoid let's clear that canister of fuel vapors so we're going to open up the purge and allow the engine vacuum here to draw the vapors out of the canister and restore the um or or just empty the canister of the vapors let me pause this so you guys can see all right so we're drawing those vapors now if you guys remember from the last class i asked that question involving a stuck open purge solenoid causing a rich or a lean condition well it's important to note look at this animation our vent solenoid here is still stuck open okay now the answer to the question was it could cause either rich or lean so we open up the purge the computer is going to account for that it's going to change field trims it's going to wash the action sensors it's going to account for that but what if the computer at this point isn't commanding the purge solenoid what if it's stuck open physically there's maybe some stuff stuck in there maybe it's rusty and it's jammed open something is causing direct engine vacuum to be applied to our evap system at all times we're going to draw those fuel vapors out anytime the engine is running so if that canister is now saturated with vapors we're going to draw those out engine running what are we going to have we're going to have a rich condition in our engine the computer isn't preparing for this it didn't open the purge solenoid so it isn't prepared for it so we're going to have a rich condition but what happens when we use up all those stored vapors what happens when they're all gone well our vent solenoid is open connected to fresh air we're going to draw that fresh air right out of our canister into the engine and cause a lean condition so really our stock open purge on it can definitely cause rich or lean concerns depending on saturation of the canister depending on fuel level and many other things but the answer was both both conditions i just want to see if there's a bunch of comments on here all right you guys are commenting in a bunch good no emissions controls we used to call that freedom all right well unfortunately if there were no emissions controls nowadays we would all be in a very smog ridden planet and that just wouldn't be good all right so let's get back to this all right let's talk open this one up so let's talk some diagnostics now now i'm not going to go to the vehicle quite yet i want to talk through some of these different options and different things before we get to the vehicle so common customer evap complaints first and foremost we're going to see the check engine light on for some sort of evap problem an evap related code it's less common to have any sort of drivability problem you know not like a misfire code a lean code a rich code a transmission code something like that most customers are not going to notice any sort of issues drivability wise with an evap problem you're not going to have a drivability issue for an evap leak now there are some conditions of sticking open purge or vent solenoid something like that that could cause drivability concerns so this unable or hard to refuel pumps keeps the fuel pump keeps clicking off and that's the the nozzle at the station keeps clicking off well like i said you have to have some way to [Music] displace all those vapors and air that's inside the tank when you're filling otherwise the nozzle is going to keep clicking off so if you have a vent solenoid that's either stuck closed or plugged up the filter in here is plugged up something like that you're going to be clicking that nozzle and it's going to keep clicking off keep clicking off keep clicking off you're not going to be able to fill the system because there's nowhere for that air or fuel vapors to travel so that would be a potentially drivability related customer complaint this hard start stumble stall after refueling this would be something [Music] again related to the purge solenoid so you have this thing stuck open you're building pressure inside of the tank it needs to go somewhere when you're filling right you're dumping fuel into this thing pressure has to go somewhere well it's going to go through the canister out through the vent but what if your purge solenoid is open at this point that pressure could force its way force fuel vapors into the engine into the intake manifold and essentially cause an incredibly rich condition as you're refueling so you start the vehicle it's really rich it starts and dies doesn't start at all maybe floods out that kind of thing could be caused by a stuck open purge solenoid okay fuel smell obviously any of this stuff has few vapors traveling through it if it's leaking if it's cracked if it's damaged you could end up with a fuel smell and then you know obviously unable to pass emissions check engine light on you're not going to pass emissions so those are the common complaints here are the common codes related to evap these are going to be the obd2 specific codes anything from a 442 small leak all the way up to the 457 gas cap loose now there are way more codes than this we'll be getting more man manufacturers specific on this so i didn't want to include them because i want this to be generic these are typically the codes that you will see come up under a generic obd2 code poll okay so you have your small leak your circuit control codes a couple fuel tank pressure sensor codes uh gross leak very small leak and a gas cap loose or checked gas cap code or potentially a check gas cap light so common failures related to evap as many of you know leaks are going to be the biggest failure that we see in the shop typically you'll come in with a the vehicle will come in with a small leak largely code something like that and this is commonly because solenoids fail hoses fail dry rot over time clamps fail that kind of thing stuck open or closed vent or purge solenoids we kind of went over that a little bit already fuel contamination in the vapor canister only vapor goes in this thing this only has vapor in it if you get liquid fuel in it recommending i recommend replacing um this happens because of something like topping off the fuel tank if you're one of those people that always wants to try and round up to the next dollar or something like that if you constantly top off that tank it's possible to force on certain systems raw fuel into the canister okay so don't top off your tank when that thing clicks it's done it's full and unless you have a purge or a vent solenoid problem all right so fuel contamination in the canister it's only intended for vapors also ford on this specific vehicle right here has a problem and tsb related to the purge solenoid uh where this thing will stick open and they state that obviously you should check your purge solenoid see if it's stuck open if you find that it is stuck open to inspect they suggest that you inspect the canister pull the canister down and see if it has raw fuel inside of it it's possible that this thing could draw enough vacuum on the system that it would actually siphon fuel off the top of the tank and draw it into the canister if it is stuck open okay so keep that in mind any sort of raw fuel in the canister it should be replaced uh physical damage potholes speed bumps road debris that kind of thing just like brake lines fuel lines anything underneath the vehicle you could cause damage cause codes leaks that kind of thing we see this pretty often in the good old state of wisconsin with potholes our roads are in excellent condition so we see you know potential problems with that manufacturers have gotten pretty good with covering up the evap components like this one has the shield on it here you know trying to protect it trying to trying to keep it from getting damaged or a hose getting damaged anything like that they have gotten very good at uh at doing this all right and then we got wiring and circuit failures you know a vent solenoid lives outside of the car it's wiring lives outside of the car potentially could have wiring and circuit failures and then fuel tank pressure sensor issues um they're definitely more rare i know in my time as a tech i've replaced very few fuel tank pressure sensors i know when we get a lot of calls on the tech line there's people asking about replacing the fuel tank pressure sensor but it all comes down to understanding the code and basically at that point they're reading down a list of potential causes and fuel tank pressure sensor happens to be on there the sensor's job again is to monitor the pressure inside of the system or vacuum inside of the system it's possible for it to be skewed or damaged but it's also possible that something else is causing problems and that fuel tank pressure sensor isn't actually the root cause all right so leak testing how does the system exactly know if it's leaking so i'm going to get into some of these leak test procedures um i have that set up over there also but we'll get to that in just a second first i want to talk about continuous non-continuous monitors continuous well most of us know evap problems or evap the evap monitor in general for emissions is a non-continuous takes a long time to set kind of a pain in the rear to set that is a non-continuous monitor that requires very specific set of parameters to be passed in order to even run this leak test right here we are going to continuously monitor the circuits and purge solenoid vent solenoid fuel tank pressure and fuel level input this is vital for vehicles to have a fuel level input um especially newer vehicles where the computer is actually calculating vapor inside of the tank it needs to know the fuel level as well as the temperature okay here's some parameters for leak testing again these are very vehicle specific you're going to want to do this research on a per vehicle basis these parameters that i've pulled up here are for this escape right here you can see we have intake air temp 40 to 100 degrees fahrenheit okay so our intake air temp has to be within that to run the test we have to have a six hour cold soak event okay that's kind of interesting um so the vehicle has to sit for six hours in order for this thing to even try to run the test okay what's nice is our scan tool manufacturers have caught onto this and they give us this little button right here so i'm loaded into the scan tool right now under functional tests evap system cold soak time bypass it's essentially a click of the button and the vehicle then thinks it's sat for a six hour cold soak so you can try and get this thing to force run the monitor by applying that button and making it think it's after those six hours and then we have this thing can't have gone through a refueling event the system is going to check at a key cycle it's going to look for a 20 percent increase in fuel level if it notices more than a 20 increase it will call that a refueling event and it will not allow the leak test to run it will however run the refueling event leak check basically checking if the gas cap is on or not i'm going to talk about that in just a little bit uh the vehicle has to be traveling between 40 and 80 miles per hour with a fuel level between 15 and 85 percent and you have to be between 20 and 70 percent load so if at any point during the test during the leak check if you bypass or go if any of these if any of these parameters are not met say you slow down say the vehicle's in the middle of a test and you run into a traffic jam and you go from that 65 70 mile an hour mark down to 35 you just failed the test or not not failed the test you didn't complete the test so you now have to start over start at the beginning again every time it needs to stay in the parameters for the entire test or it will not complete all right so now we have the test mode i'm going to start with it on here and then i'm going to show you guys on there and then we will do some stuff on the vehicle also so let's go here so here is test mode this is how we're going to be checking for leaks so right now the engine is purging the the purge solenoid is open we're drawing fuel vapor out of this thing our vent solenoid is open right now we're in purge mode now what we're going to do is we're going to enter into test mode so what does the computer do it closes our vent solenoid it shuts the back door the back door is now closed so we now have a system that is sealed at the back with a vacuum source at the front we're going to draw this entire system all these hoses the fuel tank everything we're going to draw this all into a vacuum that is being monitored by the fuel tank pressure sensor right here so what the sensor is doing is it's watching pressure or vacuum inside of the tank so the purge solenoid is duty cycle opened drawing vacuum because the engine is hooked up direct engine vacuum and the sensors watching for a certain level a certain vacuum parameter which is going to be different for each vehicle but it's looking for a certain target level parameter once it reaches that so let's just say that it's eight inches of water which is what this escape is so we reach eight inches of water what do we do we shut the purge solenoid off so now the front door is closed the back door is closed and we're checking the entire system for a leak we're checking from between this hose clamp on the purge solenoid to this hose clamp on the vent solenoid okay all of these hoses the canister the tank everything we're monitoring it for leaks we're watching our fuel tank pressure sensors either voltage or pressure reading and we're looking for that to decay over time now again this is going to be different on every vehicle but basically we have this threshold we drop the vacuum below the threshold so this vehicle eight inches of water so our here's our vacuum level we come down come down eight inches of water we fall below the threshold we shut the front door okay front door is closed back door's closed the entire system is sealed we're below our threshold now we watch and we wait and we wait a certain amount of time depending on fuel level depending on temperature depending on the vehicle we have to wait this certain amount of time to see if that vacuum decay happens and now we'll always see vacuum decay i have never personally tested a system that didn't have some sort of decay um let me know if you guys have i'd be interested to hear if there's a perfectly sealed system out there i've never run into one but we will see some decay again there is a threshold a set amount of decay that is allowable in a set amount of time and those are stipulated by the manufacturer to determine if it's a 20 000 leak a 40 000 leak or a gross leak now i have heard and i don't know when or what models are going to have it but i have heard rumor that we're going to start to see a 10 000 leak parameter or potential test on newer vehicles so if you guys know of anything running and testing for a 10 000 leak i'd be really interested to know if there is anything out there on the road today or coming up very soon that is testing down to a 10 000 leak okay let's go over here now and i'm going to kind of show you guys with the volt meter connected to our fuel tank pressure sensor i'm going to both apply vacuum and pressure to our tank and we're going to watch as i turn on the voltmeter we're gonna watch this all happen okay i'm gonna apply our gas cap back to here here's our voltage right now so i think you guys can read that yeah 1.5 we'll call it 1.5 volts at atmospheric pressure right our gas cap is off there's no pressure no vacuum inside of our tank we are currently at atmospheric we will see this thing sit right about here now this is again a gm fuel tank pressure sensor on here what's unique about gms is if we pump pressure into this system if we use this smoke machine and pump pressure into there we're going to see that voltage go down if we suck vacuum on the system we're going to see that voltage go up which is kind of um backwards of thinking and it's actually backwards of a lot of other vehicle manufacturers so if you're checking fuel tank pressure on a gm make sure you realize that pressure will make the voltage go down vacuum will make the voltage go up so let's go ahead and do that i'm going to go ahead and close our vent solenoid is closed i'm going to close our purge solenoid so now the front door and the back door are closed and what i'm going to do is i'm going to go ahead and test this system i'm going to start with vacuum so i'm going to put a vacuum pump onto our purge solenoid here and now i need to reopen this valve in order to draw a vacuum on it so i'm going to open our purge back up and before my hand cramps up we should see this thing drawing vacuum and you can see vacuum is being applied and our voltage is going up so let's say the threshold in the computer for this vehicle is let's just call it four volts so i'm gonna draw this thing to a four volt mark okay right there we are gonna leave it sit there and i'm gonna close up the purge so i just disconnected the purge the purge is now closed i'm going to pull the vacuum pump off of here and our front door and back door are now closed that's our vacuum decay watch it drop we are losing vacuum on this system the system is potentially leaking now again i mentioned that there's no such thing or that i haven't run into a perfectly sealed system so do we know if this is acceptable or not is this acceptable leakage or not that's going to come in where you watch the voltage and the time according to the parameter that the code sets for and then you can determine that okay so right now we're sitting at that now i'm going to show you guys if we had a leak i'm going to try and get this cap off and create a slow leak i'm going to try not to drop all the vacuum in the system maybe there we go oh maybe not oh all right so we dropped all the vacuum we're back to atmospheric pressure i couldn't get it to slow leak but that would be now back to atmospheric and now if i pressurize this it's going to be the same thing i'm going to have the purge solenoid closed i actually have a piece on here that's connected to the machine and i'm just going to go ahead i'm going to do an air test on this system now remember our back door vent solenoid is still closed we're going to watch our voltage drop now because we're applying pressure and now what's nice about a smoke machine like this is it's got this little gauge here i know it's going to be hard for you guys to see the little needle bouncing around in there but it is labeled 10 20 30 000 leak and after this system stabilizes and pressurizes the entire system we're down to very low voltage and our needle is now hovering the 10 000 leak mark so this system is sealed up to a 10 000 of a leak so if the machine is calibrated correctly our system would be passing the computer's test because on a early 2000s cavalier they were only testing at 40 or 20 thousandths of a leak so that would be a simple leak test on a simple system now there are other ways to do it i'm going to show you guys using the lab scope show you guys using the scan tool over on our escape in just a few minutes but i'm going to go ahead and i'm going to open up the vents on it oh this is good to know so the system passes the leak test right so there are we're below the threshold for the x amount of time whatever it ends up being were passed okay the leak test is passed but now what it does is it opens the vent solenoid and it watches for our vacuum or our pressure to get back to atmospheric in a certain amount of time it has to do that quickly in a certain amount of time in order for it to pass the test for a vent solenoid blockage code or something like that something related to the vent solenoid so it's going to watch this voltage as i open the vent solenoid the computer is going to watch that voltage and it's going to look for it to return to atmospheric very quickly and again this will be fuel level dependent and temperature dependent and the computer will have a set time so there we go i just disconnected the vent and is our vent stuck because i left it plugged in too long oh she's warm i think our vent solenoid is stuck don't leave your vent sound like plugged in for 10 minutes there we go it just opened and you can see it returned back to atmospheric so this vent sauna was was turned on this whole time that i was talking so that is why it probably stuck and it's also been on this machine for quite a while so um all right so that is that vent check it's going to check for the blockage in that system by watching the bleed up time after the vent is open all right let's go back over here got a couple more things i want to cover before we whip out the lab scope and the scan tool and get to the vehicle i know that's what you guys are waiting for the fun stuff right um let's just say i want to just check out the comments and see if there are anything i'm missing all right eric oh is here keith is here ah yeah eric you're probably right the smoke machine pressurized the vent too much and would not allow it to open so tapping it did open it up here you are probably right on that one all right you guys are talking of today again awesome all right let's get back to the task at hand so i was talking about thresholds and levels here is the one for our escape now fortunately we have a ford in here i was able to pull that ob2 theory and operation page up and get this information so we have eight inches of water is our spec and for those of you guys that aren't engineers or don't understand inches of water because i definitely didn't or don't that is equivalent to just over a quarter psi two and a half inches of water which is our bleed up spec is just just under a tenth of a psi so we're working in very very low amounts of pressure that is why you have an evap specific smoke machine that is why you don't go applying shop air to your evap system we're working with a very very small amount of pressure that the system is testing with so i went through these and i kind of just went over what they were and put them in plain english so i could sorry about that so i could understand them basically if you have a gross leak so p zero five five four five five gross leak i could have stopped bumping the middle button on this mouse um you're gonna see that the system is unable to achieve that eight inches of vacuum over a thirty second evaluation so basically the back door vent is closed the purge zone is open and the computer's watching the fuel tank pressure sensor and trying to achieve that threshold of eight inches of water or roughly just over a quarter psi of vacuum in that system it was unable to achieve it it must have a large leak now that same test is done directly after a refuel event remember we were talking refueling events how the computer watches that 20 fuel level change it's going to check for that that is going to be the gross leak cap off p0457 this will set that check gas cap light it is looking for again unable to achieve that eight inches of water after 30 seconds after a refueling event okay so that is that gross leak then if we get into our leak spec greater than a two and a half inch of water bleed up over 15 seconds so if we have a 40 000 like a p0442 we've now drawn the system down our front door was open our purge was open drew the system down to that eight inches of water shut the front door back door was already shut now we're gonna watch right we're gonna watch over 15 seconds of time we're gonna look for that eight inches of water to increase by more than two and a half inches of water so if we we'll call that threshold then that would be what five and a half inches of water would be our threshold if we cross that line in 15 seconds or less we're going to set a p 0 0 p 0 4 4 2 40 000 leak after it fails numerous times in a row if it holds under that threshold for more than 15 seconds but less than 30 seconds then we would be setting that very small leak that p0456 code because we still lost that two and a half inches of of water vacuum in there but it took longer to do so it must be a smaller leak right and then this vapor generation limit stuff i'm going to get into that in just a little bit all right so here is some cool little flow charts um that i had found from ford this is some interesting stuff i'm not going to go through them completely but i'm going to let you guys you guys can do that if you wanted to pause and watch this again but basically i'll do the 20 000 you start you run the test or the conditions met yes or no if the conditions are met it checks for a refueling event yes or no if it wasn't a refueling event we're going to go ahead and open the purge and pull down that to that target vacuum that eight inches of water and then we're going to check to see if the vehicle was able to obtain that and if it's at idle if it's at idle we're going to close the purge and we're going to start to measure over time we're going to be watching that system over that 30 seconds or 15 second window whatever it was and we're going to look for that bleed up for that 20 000 threshold if we bleed up greater than that threshold we're going to set a very small leak that fault management is going to take two driving cycles and then we're going to set this cool little light i don't know if any of the ford vehicles i have ever been in have set this style check engine light but for whatever reason ford decided to use this in their their chart i think it's kind of cool maybe we'll see that on the dash of some of our newer vehicles but basically this is just the way the system operates in a cool little flow chart that might be easier for some people to understand all right now we want to talk a little bit about eonv engine off natural leak natural vacuum leak checking this is something that has been around for a while now california compliant typically vehicles will have this i'm going to be talking specifically about this vehicle here again you're going to be wanting to check your service information for the specific vehicle that you're working on but on ford this vehicle if it was california emissions compliant would have a stand-alone i call it standalone it is internal of the pcm but it is a small processor inside of there that doesn't require the pcm to wake up in order for it to be operational so basically this allows us to to check the evap system without waking up the pcm and drawing a ton of current and killing our battery so the inputs that are monitored by this little we'll we'll call it this little computer inside of the pcm it's going to monitor our fuel level and our battery voltage okay if it says that both of those are good it's going to close our canister vent and it is going to check and run a leak test okay there's four stages of this testing and again it's going to monitor our fuel tank pressure over time with the evap vent sound light closed and it's going to watch for vacuum or pressure thresholds to be accomplished okay so it sounds maybe a little complicated we need to understand that as fuel sits in your fuel tank it's constantly creating vapors hot fuel is going to create more vapors cold fuel will condense the vapors will condense and will actually draw vacuum so if you have hot fuel you're going to increase pressure in the tank and if you have if your fuel is cooling as the system cools you will create vacuum in the tank so that is where this little graph comes in i think this is a perfect visual representation of what this system is doing so we have p0 this is phase one this is our stabilization phase so from start of test to whatever this mark is maybe 120 seconds in something like that we're going to allow the system to stabilize at this point that little processor that's inside of the pcm will turn on our vent sonar it's going to close our vent at this point the front door is closed because the purge solenoid is always closed we just close the back door the system is sealed now at this point the computer is going to watch to pass one of these thresholds so if the field is hot and it's creating a lot of vapor we're going to create pressure and we're going to try and pass this positive pass threshold and if it's cool and it's condensing we're going to drop and pass this negative pass threshold if it's unable to achieve either of these it's going to run to phase two if it passes this threshold on either of these after phase one the test is complete and it passes but the computer doesn't oops sorry about that computer doesn't give up after one try it will go to phase two re-stabilize and then it'll open up to phase three phase three it's gonna watch it again except for a longer amount of time and as the fuel cools our vacuum will increase in the tank we'll see vacuum in the tank our fuel tank pressure will drop our vacuum will increase and we should cross this threshold after sixteen hundred seconds of time if it doesn't cross this then we have a small leak in the system so at any point between here and here if we cross we're happy the system's done passes the test moves on if it doesn't we run the test again at some point if it fails that one also then we maybe set a pending code or trouble code hard code at that point okay so with all that being said vehicle comes into your shop with an evap concern where do you start well you got to drop a plan right you got to start with your customer complaint the check engine light figure out what's going on with it and then from there this is probably the biggest tip that i can give you guys today don't go and spin that gas cap tight don't touch anything on the system until you've tested it right we don't want to potentially create or or fix a problem that was in the system without testing because then you have nothing to to stand on if you were to have that car come back so i never touched the gas cap until i've tested the system for a leak so you could check your freeze frames and mode 6 data look at your code set criteria you know obviously go into your service information you want to see why that code is setting and then from there it's just your standard diagnostics verify the fault is currently present prove it repair it verify that it's actually fixed you know my story last time with that bmw always verify your repairs and then you get to sleep easy at night knowing that it's properly fixed and you have the data to back it up okay um i'm going to take a moment and bump over to the scan tool here i want to show you guys some mode 6 information that might be helpful to you guys so i'm in generic functions right now on the scan tool and i'm going to start with mode 6 and i'm just going to see what we have available to us on this vehicle i'm going to have to turn the key on if i want to do this all right key is now on and as we load here we should have some hopefully deciphered information from the scan tool manufacturer on this one again if you watched our mode 6 class you'll know that all of our information isn't always deciphered nicely for us sometimes you got to look up those tid sids and mids but we have information here so we have a purge flow monitor and an evap monitor 40 000 leak let's just take a look at that 40 000 leak test and system monitor ready yes enabled completed no i recently cleared the codes in here that's probably why we're seeing no's on this but we did pass the test value of zero min and max of some high numbers here again what i'm looking for here is i'm looking for this value to be close to that min or max could potentially cause an intermittent problem you know if it's hovering right on that edge right in that line we're looking for that because that can help pinpoint an intermittent problem also we can get out of mode six and we can go if the vehicle has it to mode 9 in-use performance tracking and we can see how many times it's run the test and completed the test so again this is information is not always going to clear out right away i cleared the codes in this thing yesterday and there's no way that i've started this engine 4068 times since i cleared those codes so here's all of our tests that we're running all of our monitors we're running and evap at the bottom here we've completed the conditions times and we sorry we've met the conditions 234 times and we've completed the test 743. so those numbers are nice and high this thing's running the test completing the test like it's supposed to if you're running into a vehicle that won't pass emissions you know the little old lady that drives to the grocery store in church on sundays has only single digits in there you might have to go out and drive the vehicle but this is proof that the test is not even meeting the conditions to run so if you have single digits in there you might have to go out and drive the vehicle for the customer because they might not meet those conditions they might not go above 40 miles an hour they might not um for whatever reason any of those conditions might not be met um intake air temp 40 to 100 degrees is this going to run are we going to see that that condition run in the middle of winter in wisconsin on startup there's no way that we're well last winter we did have some nice days but generally speaking in the winter you're not going to run an evap test because intake air temp is not high enough okay so you can look at in-use performance tracking for that that is going to be found in mode 9. not all vehicles are going to have this it seems to be on newer newer models again we're working with a 2010 escape all right let's just talk for a second about equipment for evap testing do you need to have a lab scope do you need to have a full function scan tool do you need to have all this expensive equipment to get into testing for evap and the answer is no you can do the entire test with service information a code reader a dvom and a fused jumper lead you want to dvom to monitor your fuel tank pressure or potentially a cheapy scan tool that you can monitor fuel tank pressure with um you need to monitor that and then you need to be able to jump the vent closed and the purge solenoid open for a short amount of time seal up that front door and back door and watch your fuel tank pressure right watch what happens you have a vacuum pump in the engine you have a oh what did i see i saw a facebook post and one of the technician groups that i'm a part of and a guy brought up testing the system using vacuum and he had this vacuum pump set up and he had hoses running to the vehicle and he had a little pressure gauge and he had a vice grip on there and i asked in there i asked what is why do you use that whole setup when we have our vacuum pump we have our vice grip which would be our purge solenoid that's our door cutting off the vacuum we have a pressure sensor already you know what is the point of going through all of that extra work hooking that all up when you have it available on the vehicle already for you to use as long as the engine is idling and under vacuum so he he hasn't replied yet but my only thought would be maybe if you don't trust your maybe if you don't trust your fuel tank pressure sensor or something at that point um now today i'm going to be using the lab scope i'm going to use the scan tool and we're going to look at this system as a whole on the lab scope oh vacuum gauge would also be be useful if you're checking the purge solenoid for being stuck open you just throw a gauge on it at idle and you can see if you're if you are leaking all right so i'm not going to go too far into all of this here because i'm going to talk about it as we go through this but visual inspection when looking at leaks is huge look for for cracked hoses deteriorated components hose clamps anything like that chrysler v6s are super common for those hoses underneath the air box we've all seen those before so visual inspection is key then you want to verify if the leak is actually present either with the service bay test or the manual leak test smoke machine make sure it's an evap smoke machine you don't want to over pressurize the system and then you're supposed to use pressurized nitrogen i don't know how many people are actually doing that but essentially they want the manufacturers want you to use an inert gas when you're pumping something into the system that's going in with fuel vapors and fuel you don't want to be pumping oxygen into there because oxygen fuel what do you need you need some sort of ignition source and you have a um an event we'll call it that so you don't want that to happen so you're supposed to use pressurized nitrogen but how many of you guys have a nitrogen tank for for evap checking i'm honestly curious to see if there are people that actually have it and then this this co2 deal with a sniffer and you you apply co2 to the system i personally have never used it i've seen it demoed and it seemed like a pretty cool little tool um if you guys have ever used it i'd really be interested to know if it works nice if it's worth the money if you like it more than your smoke machine i've always been one to use the scan tool smoke machine and that has gotten me where i need to be um but yeah let me know if you if you're using that co2 and that sniffer um for for testing for leaks uh purge issues i'm not going to get into these because we're going to kind of go over them when i work in a car vent issues same deal voltage dropper load test these things you know again you don't trust that you have 12 volts there and you're happy do a voltage drop or load test it because 12 volts might not be able to flow any current these things take current to open and close okay don't get beat by that uh fuel tank pressure sensor issues less common we don't really see it all that often um scan tool pid you'll typically see a voltage reading and some sort of pressure inches of water psi inches of mercury something like that i found this nice little graph here so on our escape at 4.9 volts fuel tank pressure we are reading 16.6 inches of water and just for reference 15 inches of water is equivalent to about half of a psi remember your fuel tank pressure sensor is your brains of your operation if that's not functioning if you can't trust that you're going to have to use something else and also there are fuel tank pressure sensors out there that are not mounted directly into the tank they're mounted with a small hose on one of the vapor lines or something it is possible for that to become blocked or restricted and then you got to really be watching your values so that could be interesting to to look for okay lastly before we get to the vehicle or vr on board refueling vapor recovery systems this has been something that's been around for a little bit now but we're seeing it become a lot more popular what it is is it's basically an add-on to the evap system that the standard system could not do and that was contain the vapors during a refueling event refueling was the largest polluter and this started in the late 90s basically we now have a one inch filler neck that when you're pumping fuel down it there's not enough space it creates a liquid seal and doesn't allow vapors to travel back up in the neck there's also usually some sort of refueling vent valve on the top that is going to allow the pressure build up from dumping excuse me from dumping fuel into the system that's going to allow for that pressure to be vented into the canister very quickly and then we typically will have a check valve or float at the base of the filler neck that will seal off the filler neck to not allow any sort of liquid fuel to travel up that neck and then we also have a larger higher capacity charcoal canister uh stage two vapor recovery it's not on the vehicle but i think it's good for you guys to know how many of us have seen fuel pump handles that look like this you know with the little rubber at the end that's basically a vacuum at the end this is hooked up to the fuel pump at the station and basically they would vacuum any vapors that would come back up from the filler neck while refueling they would vacuum those and suck those back into the into the tank to not allow them to to get out in the atmosphere the problem with this is that since our vehicles are now running our vr systems those vacuums are just sucking fresh fresh air and whatever is in the air in that day but they're just sucking fresh air and putting that down into the tank now i've heard that those vacuums can actually build enough pressure inside of the tank that it opens a relief valve on those tanks and lets fuel vapors out that way so in 2012 the epa determined that onboard vapor recovery systems onboard refueling vapor recovery systems for gasoline vehicles has been widespread they basically are saying here in all of this all this talk here that these stations that have this right here are able to start removing them and it's going to save these stations 91 million dollars annually so our vehicles have advanced enough that we don't need to have stage two vapor recovery anymore our orvr systems are good enough all right evap two this is gonna be our next class check out our tech connect episode for that on june 30th to find out what that one is going to be about let's play with the vehicle now i know it's already been an hour guys but i have some cool stuff i want to show you on the vehicle and i hope you guys will hang out for it because looks like everybody's still here helium as stars using helium because he likes his high pitched voice nice all right okay um all right let's play with the vehicle now so now as you guys know and i've said multiple times before i like to work smarter not harder i'm kind of a i don't want to say lazy but efficient as a technician and if i were testing a system and i was running into problems errors something like that i don't want to work harder than i have to fortunately for our escape right here this is a 2.5 liter in here if you guys look our pcm is nice and easy to access so at the back of the firewall here you guys can see oh just ignore this this was a a used engine that i put in here but our pcm is right back here so instead of having to back probe at the fuel tank pressure sensor instead of having to back probe at the vent sonoid instead of having a back probe at the purge solenoid instead of having to find all that stuff i printed off a diagram found my connections at the pcm and back probe right there now not every vehicle will be this easy this one just happened to be so i'm gonna go ahead and set up the scope and look at some of this as it operates in the system so i'm going to start with our fuel tank pressure sensor and that is going to be on channel a and that is going to be this guy right here hey fritz can you turn the key off for me thank you all right so channel a all right let's get back to our scope here okay channel a i'm going to throw it on uh we know our fuel tank pressure sensor is probably a 5 volt so i'm going to just throw it on 10 i'm going to bring it our offset scale i'm going to bring that down and we'll run this we'll put zero there so we're running zero to seven just in case it ends up higher for whatever reason i don't think it will and because i get confused sometimes i'm gonna throw a label on this we'll call channel a fuel fuel tank pressure there we go so channel a is now fuel tank pressure so currently our key is off we're sitting at zero volts so i'm going to go ahead and i'm going to throw on our let's throw our vent solenoid on next vent solenoid is going to be our red channel and i'll bring up the wiring diagrams in just one second here to show you guys what's going on so our vent solenoid is going to be pin what is this pin 20 i believe make sure i got it right yep pin 20 of the pcm ground our scope on the other lead and let's turn on channel two so i'm going to throw on a 20 volt channel here what's going on where we go oh we may be froze okay i'm gonna start closing things out and hope hope we get channel two here some at some point doo doo doo doo doo doo hey there's channel two okay now fritz the key is off right okay interesting huh 12 volts on channel two 12 volts on our vent solenoid wire now did we expect what did we expect here well i suppose it's hard for you guys to know what to expect if i didn't give you a diagram yet so let's take a look at that as soon as i label this channel vent um canister no is there a vent solenoid label in here evap vent we'll just call it evap vent all right so let's bring up a diagram all right so this is our purge solenoid so when i hook up our purge solenoid this is what it looks like um pin one is gonna go back to the pcm i'm gonna assume that this white and brown wire is probably ground side control that would be my guess this would be our ground side control and we're sharing power from pin e right here because we're not going to ground side control all of these components at once right so they're probably shared power let's look where pin e goes uh pin e goes here to a splice to a fuse that comes from a so fuse uh 28 20 amp fuse is going to power our pin e which is going to be our input into our purge solenoid now i wish i had one of those cool touch screens so i could draw on the screen for you guys like in like in new level uh new level autos videos he's been doing that that's pretty awesome um okay so we're there now let's look at our pin a comes from here comes through here to our pcm power relay okay so our pcm powers on the relay grounds this this side and sends power through pin a fair enough so our pcm power relay is basically the input power for our purge solenoid let's see what our vent solenoid is again oh pin a so probably back to that same place vent control solenoid looks like here ground side control i would guess this would be ground side control we are currently back probe right here on pin 20 and we are reading 12 volts right here kind of odd but let's look at pin a again okay pin a goes here pc and power relay the key is definitely off we are currently key off the pc and power relay should be open all right that looks good let's go back to our scope we are definitely at 12 volts okay so we're at 12 volts on a circuit that's really not supposed to have 12 volts on it right now at least according to what i think so let's pull this relay here can you bring up the under hood shot so maybe this is our oh can't see it anyway okay well i'm bring the sculpt back up then i'm pulling trying to pull the pcm power relay currently i should have a relay puller that would make sense and we're still at 12 volts okay i'm going to leave this thing sitting out fritz key is off right key's off pcm power relay is out and our vent solenoid right now pin 20 of the pcm and i'm 100 certain this is pin 20 green and blue i believe that is yep green and blue pin 20 at the pcm has 12 volts currently now this is where things get interesting okay so look at our diagram ground side control power flows in here i would expect to see if if this side is powered up if pin one right now is powered up i would expect to see 12 volts here because we currently have an open circuit right here we're supposed to right the pcm is supposed to this is supposed to be open it would ground side control it so if we have an open circuit here we're gonna have voltage flow through this entire thing through our solenoid so if we were to check pin one and pin two right now we would have voltage there if this is acting the way it's it is right now um we would have voltage here if we were to disconnect the connector then we would lose our voltage on pin 20. but still if we go back to this pin a comes from our pcm power relay this is open right now i have this relay out this is sitting upside down in the box and i am getting power on here now this is where we need to be careful with our service information okay so lucky me i have access to more than one source of information here is a different diagram so here is our vent solenoid pin one and pin two at the vents on it of course gray and red green and blue so again a back probe and pin two at the pcm they go to this other diagram so we'll go back to that one they come through here come through here so i'm on green and blue at the pcm pin 20 okay so this is where i'm back probed right now here's our our gray and red this is our power supply that's supposed to come from our relay it goes to splice 140 comes from our relay right so if we turn our relay on we should see power here but what is this fuse 5 10 amp hot at all times feeding down to splice 140 through pin 7 down here up to our event solenoid through pin 1 through the solenoid because we have an open circuit in our pcm right now through the solenoid back through pin two back through green and blue and back to our back probe right now 12 volts so our service information has lied to us or not given us all the information that we had initially hoped for this is normal it is normal for our 12 volts to be here i'm going to tell you why our 12 volts is supposed to be here because we need to test this thing california emissions right engine off natural lac natural vacuum leak detection needs to be able to test this thing that little processor inside of there its job is to ground control the vent solenoid right well you can't ground side control something unless it's powered up right so we supply power to our vent solenoid at all times so that this little processor inside of there that takes very little current to run is able to turn on the vent without waking everything up by grounding this and having our vent solenoid turn on so 12 volts right here on this vehicle is normal for key off engine off hot at all times now could this create problems down the road could this create parasitic draw problems could this create just a numerous amount of problems definitely we have a power supplied circuit at all times going to a component that's underneath the vehicle in the environments in salt spray and everything else that we deal with in wisconsin we could have parasitic draw across our vent solenoid connector or anything that would potentially draw enough to kill our battery because we're powering this thing up at all times okay so keep that in mind to know exactly what you're looking at and trying trying to figure out and again don't always trust every bit of service information you read if something doesn't seem right check another source okay that being said let's hook up one more channel i'm going to put our purge solenoid on now that's going to be on channel c that is going to be our green channel make sure our ground stays connected and that is going to be here and now we have that on and we'll turn that on we'll go 20 volts on that and okay so green is sitting at zero volts so i'm going to bump that down so it lines up with our blue so green and blue are both at zero so our purge solenoid is not powered up all the time which makes sense we don't need to have it powered up all the time because it's not used for that engine off leak detection check so this is vent solenoid i want this all right what am i doing wrong here canister purge it's not giving me a canister vent vapor all right well then we'll just label this one and then the one in the middle will be the one in the middle will be vent oh maybe i could just go like this add vent there we go now we have n solenoid on there okay so purge inventor or excuse me purge and fuel tank pressure both at zero vent is sitting up at 12. you want to go ahead and just turn the key on fritz ah yes put that pcm relay back in good call okay yep go ahead turn it on so we saw our voltage bump up for our fuel tank pressure we're up sitting at what is that right around uh 2.6 volts or so um our channel b here our voltage at the purge solenoid is currently at 12 and i would expect to see that because again we're not grounding our purge solenoid so i'm going to go back to this diagram we're not grounding this right now so we have an open circuit where we're checking we're back probed right here it's open on this side we're gonna have that 12 volts flow all the way through the solenoid to our back probe okay that's normal um okay so this all looks good our fuel tank pressure is there now it's possible that this thing has either generated vapor inside or gone into a slight vacuum so what i'm going to do is i'm going to start by seeing if this thing will change i'm going to increase our time here so we get a little bit more time on the screen go 200 milliseconds i'm going to slow this way down because i found when testing that we had a ton of hash when looking at the fuel tank pressure sensor so i'm slowing this scope way down right now we're only capturing 4 15 000 samples currently but i found that this was the best way to reduce hash on our fuel tank pressure sensor what i'm going to do now is i'm going to actually bring this up to 500 milliseconds and so we're at a half a second per division i'm going to go ahead and take this super special cool tool that's usually mounted right next to that locking lug nut tool that you can never find it should be somewhere in the vehicle on a ford and this tool is to open the fuel filler cap essentially this tool fits right in here and what i'm going to do is i'm going to open the system just like when on the other system where i took the cap off i'm going to open that or i'm going to have fritz open that we're going to watch our fuel tank pressure to see if we generated either any pressure or vacuum inside of the tank so fritz you want to shove that in there and see if see if we did anything as this thing was sitting yeah go ahead and we'll see if we get any change no change and that's because our vent solenoid was open the whole time right i wouldn't expect to see any change at this point because our vent solenoid wasn't closed now if the system was going through a test and our vent sound was closed and we saw zero volts here then i might expect to see a change but uh okay let's go ahead and fire this thing up you want to take yeah take that back out we'll hide that next to the locking lug nut key and uh we'll fire this up and look at how this thing reacts all right i'm also going to go in the scan tool here guys and dave if you want to bring up the scan tool in the lower part of the screen so they can watch both at the same time i'm going to go in data display there we go beautiful and we're going to look at some emission evap data and look at that on the scope the purge solenoid just kicked in this thing is purging at idle and our scan tool should tell us that so i'm going to go in custom graph and i'm going to take a bunch of this stuff out let's go vent valve mission sure we'll go to that soak time very small let's go we'll go fuel tank pressure and we'll go purge cycle our purge duty cycle we're going to graph view all right so we are definitely purging right now we're at a 60 70 duty cycle on purge our vent is open and we should see that somewhere event valve here zero percent so our event is open obviously vent valve off and our purge is currently at 81 duty cycle so again this is just a a square wave duty cycle in here looks good so what i'm gonna do now is i'm gonna go ahead and um i'm gonna go ahead and i'm gonna i'm gonna play with the scan tool and and do some actuation control so again i'm going functional tests and i'm going to go output controls and let's control this vent solenoid so i'm going to turn this thing on and off now can you bring the scan tool full screen for a second please full screen on the scan tool all right now i'm going to go ahead and i'm going to grab some data out of here related to our fuel tank pressure maybe our fuel tank purge deselect all hmm so snap-on put together this nice list of data related to you know the evap canister vent solenoid what do you guys think i don't see anything in here related to the evap evap solenoid you have vents all night oh i see fuel system status that's about the closest i get so i don't want anything so i'm gonna push all right it's gonna force me to grab something okay we'll grab that well thank you uh to the software uh for not allowing me to see what i wanna see basically i wanted to close the vent with the purge stuck open and watch your fuel tank pressure right but with this software version i am apparently unable to do that so let's watch now on the scan tool i'm going to open up or close the vent i'm going to turn the vent on which would close it sorry let's let's watch on the scope i meant to say i'm gonna turn this on and i would assume as soon as i click this it's gonna cut our purge solenoid off oh the computer keeps it on okay so our look at our fuel tank pressure we're dropping we are currently dropping we're doing what we're supposed to again do we know what the numbers are potentially oh we must have dropped low enough that the computer said okay i'm going to shut the purge solenoid off and now at this point we would watch the bleed upright and slowly we are bleeding up now it's not happening quickly and i didn't expect it to because this vehicle does not have a leak but we are bleeding up very slowly and then if i go ahead and turn our vent off there we go i just turned it off and look at our pressure return and the computer said i want to purge right away and turn the purge solenoid right back on so sometimes you can do this with a scan tool gm is pretty good with the evap purge sealed test but sometimes you can't and obviously i can't even view the information i want to view with the scan tool so we can do this all again with just using the uh just using a fuse jumper lead and the stuff that we have um i could hook up the dvom i could put that into the fuel tank pressure circuit and monitor that on the dvom i like to see it on the scope because i want to see it over time um it's just it's just nicer looking for me so what i'm going to do now is i'm going to actually back probe the purge and i'm also going to back probe the vent and i'm going to short both of these to ground so i'm going to act as a pcm here now watch on our scope as i do this so you'll see our vent our red line will go to ground so our vent is closed the computer is currently not driving the purge solenoid so i'm going to drive it i'm going to turn our purge on 100 and there we go our purge is grounded our vent is grounded look at our fuel tank pressure drop and then at some point here after i cross that threshold whatever it may be i would let off of here so we'll bring it down just under one that looks good we're under a volt and i'm gonna leave it sit so i ungrounded the purge the purge is now closed our front door is closed our back door is closed and now what i'm watching is this i'm watching our fuel tank pressure over time to stay below our threshold so if our threshold were one and we had to do it for 15 seconds and maintain under one if this was say this was 15 seconds we've currently looks like we've crossed the threshold we're above one this would fail the test if if that was our threshold okay and then if we pass the test if the computer says okay i'm happy i'm not leaking it's going to open up the vent just like i talked about over there it's going to open up the vent and it is going to watch that fuel tank pressure sensor to return and i'll do that here and you guys can see pressure should return there we go so our vent is now open our purge solenoid is closed and while not have available scope to do it i like using the scope because i like to look at things over time event a dvm will work just fine too and then when it comes to circuit checking testing your vent and purge solenoids when they're grounded by the computer this thing kind of rains supreme right test light incandescent test light is a small amount of load it's going to be less load than the solenoid would put on the system but it's enough that it could maybe uh weasel out those those problems that where you're still getting 12 volts but you're not getting the current behind it to actually to actually do anything a test light will help you with that so um always keep a test light with you i guess and use it use a test light when you're checking your circuits because on on most circuits you can use it be careful with some computer controlled circuits you don't want to be loading some um with that small amount some can't handle it so know what you're you're testing before you get there and uh yeah as you can see i don't have a power probe anywhere i don't use them it's a personal choice i use something like this if i want to supply power or ground i'll use a fuse jumper wire on there just because it's it's the way i was taught in the way i do it uh you guys probably have or used power probes more power to you i've seen other guys wreck things with power probes so just keep that in mind um when when circuit checking okay oh man i think that's probably about it um i guess i could just show you really quick i'm gonna pull the pull the holes off the top of the purge so i got it in my hand here if we look under the hood if we bring up that camera okay so we got the hose off the top here and the purge solenoid sits right down here i know it's gonna be super hard for you guys to see but it is right there i'm pointing to it i don't know if you guys can see it or not but uh what i'm gonna do now is i'm just gonna do a quickie quickie check on this thing got a vacuum gauge or a vacuum pump you could use a gauge whatever i just have a pump here that i'm using as a gauge i'm gonna throw the hose over the canister side of the purge and i'm gonna have fritz fire this thing up and we should not see any vacuum on this unless the computer is commanding it yep go ahead so you didn't see the needle move at all right that looks good now at some point i would assume the computer would start to command this thing we'll see if it does and then we would see that there we go so i'm watching the scope out of the corner of my eye the computer just turned it on and there we go we're applying vacuum our needle is moving we're playing back into the system purging out those vapors so that's a real quick easy check um i what i do is i unplug the connector with the connector unplugged the computer obviously can't control it you should not see anything on your gauge move your gauge should not move with that connector unplugged if the purge solenoid is functioning properly okay perfect all right go ahead shut her off i think i talked enough holy cow hour and a half oh okay i'm just gonna take a quick scan through the comments oh new level auto you're saying pierce it make make sure you have the best connection i hope you're i hope that's the sarcastic little image after that my lab my laptop here is not loading it um i i don't like to pierce um connections it creates unless i have to it can create problems um i like to back probe that's what i like to do or wire in some sort of t connection where i can get into it just going through you guys are talkative today now i will go through all of these later um as a as new level auto found out i did i do go through every single comment that you guys put in here and um get back to you on it um i'm just seeing if we're there okay i'll open it up to you guys are there any comments questions that you want to see right now well i still have everything hooked up to the vehicle is there something that i maybe didn't show that you've always been curious of that you want to see with a scope um with the scan tool anything like that maybe you don't have access to the tools is there anything else that you wanted to see before i close this out for the day um [Music] let me know right now i know we got about a 30 second delay so i'm going to stand here and read through the comments in case you guys uh in case you guys comment in all right this is amazing guys i love seeing all this talk all right it looks like uh eric always doing an escape evap issue he mops the floor with me and ends with a well good thing you didn't give away the ending because who would watch it if you gave away the ending all right uh yeah backs rock two um you asked if the vent is only closed when the purge is on uh the vent is only closed when the system is testing for leaks the vent is open when the purge is on um unless it's leak checking so just like in that little animation that i had um here i'll bring it back up just so you can see it again just in case it wasn't clear in purge mode so we're in purge mode right now our purge our vent sound is still open it's still going to be open because we don't want to draw vacuum on the system right now we don't want to kill this thing with vacuum right now but we're going to open up our purge and it's going to allow us to draw those vapors out and we are going to get some fresh air most likely with that too but we'll draw all that out together so our vent is open when we're purging the only time the vent is going to close is when we are performing a leak test okay hope that makes sense um how much pressure for a smoker well if you guys saw and maybe you didn't see because it was kind of hard to see but our our smoke machine over there has a gauge on it and that gauge when i was pressurizing it was about 12 inches of water okay remember 15 inches of water came out to be man i really should have that memorized 15 inches of water was like what half a psi i think it was let me get back to it for you guys because i don't want to say the wrong thing and i don't i don't have any of these memorized with inches of water to psi yeah 15 inches of water half a psi so our smoke machine was testing with just under half of a psi of pressure okay [Music] so yeah one psi max on a good one right yeah you don't want to be over pressurizing the system and like you guys saw and like eric oh commented when that vent solenoid was actually stuck closed it was because the system was over pressurized at that point no time limit on education i'm sorry guys that this one went so long i'm glad everybody stayed with me we actually have some guests in here that look like they're probably bored out of their minds right now but i told them it was going to be about an hour class and as you can tell it kind of ran over so um i think that's going to be about it for today um unless there's anything else again could you bring my email on the screen dave again answer the question send me an email out to that email address if you haven't done the survey yet please do check us out on all the social media facebook instagram linkedin and twitter search for wells vehicle electronics um at the end of the today i will be drawing for the tech shirt giveaway um and then i will be announcing who won it in the july class um i'll be announcing what the july class is about in the next tech connect episode as well as getting to some of these comments and questions that you guys might have asked that i probably missed because there's about 74 000 of them um so okay i think that is gonna be it so thank you guys for sticking with me thank you for being there i really appreciate it i hope everybody learned something and i hope you guys don't turn away evap problems now i hope there is a better understanding and next time we're going to get into the other systems okay so thanks again and we'll see you next time happy wrenching

Channel: GoTech

Views: 637,498

Keywords: wells, training, live, diag, test, check, engine, light, evap, leak, smoke, valid, emission, fail, monitor, trouble, issue, p0442, p0443, p0446, p0566, p0456, p0457, p1451, ford, chevy, dodge, chrysler, fusion, taurus, honda, civic, toyota, camry, avalon, f150, truck, car, silverado, impala, grand prix, grand am, v6, v8, mercedes benz, audi, vw, bmw, jetta, passat, c300, a4, a6, 330, 325, windstar, freestar, blazer, trailblazer

Id: g4ClmBASUco

Length: 90min 59sec (5459 seconds)

Published: Thu Jun 01 2017