Silverado Running Rich? I may have found the problem! P0172 P0175 4.8 5.3 6.0 6.2

hey good afternoon everyone so what am I working on now I've got a 2014 Chevy Silverado with a 5.3 direct injected and customers complaint is to check engine light he said he already replaced both up stream O2 sensors okay uh he went to a parts store and scanned it and um codes are for fuel assist fuel trim Rich both Banks left and right common failure for fuel trims is O2 sensors but you actually know I shouldn't say that not that those two sensors it's usually are seeing exhaust leaks create this problem I've seen vacuum leaks create this problem an exhaust leak before the O2 sensor or around the bung where the O2 actually goes into the exhaust I've seen that crack and create codes like this but now it's reading Rich that could be misleading a lot of times a vacuum leak will create Rich codes believe it or not so I got my scanner hooked up right now and let's just verify the codes I already brought it up and I just want to show you so here you can see both fuel trim Rich bank one and Bank two okay so just shut that off now this truck has a hundred and eighty one thousand miles on it let me skip back here for a minute I want to go to data and let's see and we have fuel trim data those are going to show me it's not totally a skew it's off a little bit not even no it's it's good it's as far as I'm concerned that's fine here's my guess on this only because that looks the numbers look good I would have no issue with those numbers my my guess here see that you see trim on two went up to seven for some reason or negative seven for a little bit now the negative number means it's pulling fuel away positive number means it's adding plus or minus two three four is relatively normal you kind of want it like close to zero uh but see it keeps going up like negative six negative seven before when I actually looked at it it went up to a negative 16 at one point so what could cause something like that well there's there's a couple of things a vacuum leak an intake vacuum leak um to the cylinder head can create that an air leak after the mass air meter uh but before the throttle body can create that like if the boot is cracked or something like that it can actually create that because it's not reading the air going in correctly so what I'm going to actually do is I'm going to take my scanner underneath the hood I'm going to spray around the intake with some carburetor cleaner just to see if I get any spikes in the readings if I get spikes in the readings and I know it's sucking in the carburetor cleaner and then obviously I have a vacuum leak I got a funny feeling it's not a vacuum leak though I think it's the mass air meter I think the mass air meter might be reading a skew I might take it out and clean it but let me let's put my scanner underneath the hood and let's spray this thing up a little bit and see if it changed anything I haven't done anything to the car yet so this is all new to me too place that there let me go out here I just want to give myself enough slack too with the scanner cable oh let me go let me get my door open stay open all right so now stay there come on come on baby all right stay right there now what I'm going to do is I'm going to spray up around the ends in there with just some regular gum out carburetor cleaner now I know some people actually hang on one second I know some people get scared of spraying carburetor cleaner on the engine and the engine is hot now yes it can catch fire uh use your brain use your head um if you're spraying it and you see changes or whatever then you know you found an issue um but if you're spraying it a couple fire stickers are handy I got several laying around the shop here that I can use uh a lot of times though you spray it with this or even gasoline if you were to use gasoline and spray it it's just going to burn off that gasoline or that carburetor cleaner and then go out you know unless you have like a lot of leaves or you have a lot of stuff that's flammable underneath the hood that's you know within a few seconds of this bursting into flames that it's gonna you know catch the whole car on fire obviously you've got to be careful so I'm just letting you know that that's that's a possibility a good person to plants but a lot of times it'll go right out so just gonna have a cool hit so let's do this somehow I'm just going to spray down here but let's look at the numbers anything in particular no you would see a drastic change in the numbers and I don't see that at least not for that side let me try spraying the other side of the motor anything I'm spraying it right now as we speak and I'm going up and down the intake yeah you've got nothing I'm gonna spray around here because if I had a leaf it would pick up same thing but not I got nothing I got absolutely no change so I'm not concerned about a vacuum leak so what's my next step I'm going to pop this mass air meter out and I'm going to clean that mass air meter and I want to see if it changes anything now a plugged up air filter can can create this issue also um a k n air filter sometimes if it's oiled up too much can create this problem cold air intake can create this problem I've seen cold air intakes create all sorts of weird problems I've seen them create a lack of power problems like drastic because a lot of cold air intakes are not actually cold air intakes they suck in hot air from underneath the hood instead of like that that factory setup sucks it in from behind the headlight you know in between the fender I've seen people you know you have the the cone air filter underneath the hood there and what are you doing you're just sucking in hot engine uh you know the hot temperatures underneath the hood you're not you're going to get zero benefit you're going to lose performance yeah maybe it sounds cool when you hit the gas but you you actually hurt the performance of your vehicle so I don't believe in cold air intakes unless they're done correctly um but yeah so let me shut this off and I'm going to pop that Marisa meter out and I'm going to clean it all right so it's just two Torx screws I already pulled the one out of the bottom I'm going to take this one out of the top here and then let's see what this thing actually looks like [Music] it actually looks reasonably clean it doesn't look bad you know a lot of times you'll see them really mugged up with some dirt so let me get some electrical contact cleaner I'm going to clean this thing up and I'm going to put it back in I want to see if I got any changes in the fuel trims so let's do that all right so this is what I use 2D electrical cleaner they make mass air cleaner stuff like this this stuff I find to be the best because it does not leave a film or anything on sensors you don't want to use carburetor cleaner because it will leave a film and Brake clean too so basically that's all you're going to do is just spray in there I'm going to hold this upright because it's almost out of this cleaner oh there we go you want to make sure you really clean it good now this stuff is extremely flammable so just keep that in mind I've seen people actually clean like electrical guns like this and you know go in there and like replace brushes and clean them all sudden they you know they were using this and then they pull the trigger and I think burst into flames so you've got to be careful with that um all right yeah so I'm just going to clean this out a couple more times make sure everything's good I'm gonna put this back together and see if we got any change all right so it's bolted back up hook that back up and let's start up I want to see if I got any change I mean like I said the numbers are not bad so you know why in the world it's set in the code I don't know I'm gonna have to see actually one thing I can show you all right retry that off there they are there the numbers are going up again all right so why are the numbers going up this thing has a fuel pressure regulator problem because look at the long-term trim see how high it is right now and that's how it was when I first started it now I know these things have with the direction direct injection when they're cold they have a it's built into the program where the injectors double fire and it allows this thing to uh basically run super rich for a short period of time uh and that's the reason for that is to get the catalytic converters to start um to basically start working quicker see now this is yeah I don't really see too much of a change there but now let me show you one thing else that I can do with the scanner here I'm going to go back to codes menu now Freeze Frame failure records this is going to tell me when did this occur all right so intake air and barometric pressure that's all because I disconnected the um uh mess air meter but let me come over here to po175 then I want to highlight this up here now distance and first failure 12 miles distance since last failure 21 miles so it's really hasn't gone too far since then um but now I want to see something I'm going to scroll up vehicle speed zero so the truck was idling at the time interesting no AC was on AC off for wide open throttle no transmission temperature 158 so Trinity was reasonably hot let's see what other information do I have here and about a half a tank fuel rail pressure was at 580 I'm not even quite sure what that's supposed to read to be honest with you let's see power Richmond inactive you sell fuel cutoff long term look at that it was negative 30. wow that's a high number basically that's maxed out that I was pulling fuel away let's go back real quick I'm going to take this thing for a ride and see back to data a little trim well yeah it's per that's high but now you saw the numbers before where did that how did it get so high at what point like what was going on that it got so high I'm gonna have to research this I'm gonna have to research this I'm a little stumped so you're looking um Identifix and stuff like that because what they'll do is that'll actually give me it has a section there where it gives me actual repairs uh from other shops like what they found what they did to repair it um I'm just curious I'm gonna see this I don't think this is a situation that's not super common I got a funny feeling this is something that does happen on these things so but exactly why I don't know the check engine light actually isn't even on interesting all right let me uh let me take this for a road test and blow it out and just see what happens uh maybe that'll change something I don't know you never know let me try it all right guys so I took this thing on a quick road test and nothing really changed so but one thing all of a sudden dawned on me I don't know why I didn't think about it before purge valve if the purge valve is leaking basically allowing it to you know it's not sealing and it's allowing it to pull Vapors from the fuel tank it'll do that it'll run rich I didn't even think about that so I'm going to check that real quick um before I go any further I'm just going to do a quick look if I can disconnect it and plug off the uh if I can feel a vacuum leak and then what I'm going to do is I'm actually going to plug off the line and then I take it for another ride because right now it's at negative 24.25 Left Bank One Bank two so obviously still pulling fuel away so it's still thinking that it's rich I wonder if it actually set the pending codes let's just see I might have set a pending code let's just see we got the scanner actually here just so you can see it negative 24 and 21 now okay so it's changing so okay let's go back to code real quick just want to see if there's any pending codes display codes well this doesn't have pending codes but yeah fuel trim Rich okay so it's still having an issue so let's do that let's take a look at the purge and just unhook the line just see if that changes anything all right so I got those I got the line just connected and the system is actually in Purge the purge valve is actually operating at the moment so what I'm going to do is what I did was I plugged it and I'm going to take it for a ride now just to see let me just show you this real quick so here is The Purge hose here I have it disconnected and down there you see I put a cap over it because without the cap on it you hear it it's actually operated operational at the moment so take it for a ride because that'll tell me right away is that worth getting its fuel from let's find out all right so I cleared the codes clearing the codes is not going to change the long-term trim the only way you're going to do that is by disconnecting the battery but if you notice right off the bat it's actually going to positive so let me take it for a ride and let me see what it does I got a funny feeling I might have a stuck Purge hopefully if it stops actually uh actuating the purge solenoid I could actually tell if it's leaking or not or I could I could disconnect the electrical connector I just didn't feel like doing that and inducing another code but see that it's not going that much negative it's going more positive where before it wasn't so I got a funny feeling that maybe our entire problem but let's take a ride and see what see if it changes anything all right I just took it on the exact same road test I know it's getting dark now um whenever with the light you can see me anyway um now what I'm finding is long-term trim is coming down so what does that tell you I tell you I've got a funny feeling that Purge was hanging open but here let me show you I just did the exact same road test and look at the look at the long-term trim it's coming down now out of curiosity let me just see if it set me codes no codes all right well it likes like I said it's getting dark obviously you can barely see me so what I'm going to do is uh in the morning I'm going to um unplug that uh purge solenoid and I got a funny feeling it's seeping and what's happening is what could also cause this to what but what I think is happening is it's actually sucking in um uh fuel Vapors when it's not supposed to however if the charcoal canister is saturated it could do the same thing so what I'm going to do is tomorrow morning I'm going to check that and see what I got because if the personal annoyed isn't sucking in the fact that I got no codes now and it's the only thing I've done is I disconnected that the line itself I got a funny feeling it's excess fuel Vapors will excess fuel Vapors could be because of saturated charcoal canister so I'm going to end this video here and what we'll do is tomorrow we'll pick up and I'll show you me checking the valve itself I'm going to disconnect the electrical connector and see if I've got any suction out of it and then I'm gonna have to check the charcoal canister um I don't even know like I don't know if it would be filled with raw fuel which is possible if somebody like consistently overfills the tank the possibility but we're gonna see all right so let's just end this here if you're getting something out of my videos hit that like button if you could please subscribe um yeah so we'll pick up on this tomorrow you guys have a great day right great night actually thank you so much keep wrenching

Channel: Wrenching With Kenny

Views: 31,121

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Id: 19HRO8GawJ0

Length: 18min 30sec (1110 seconds)

Published: Tue Nov 15 2022