Chevy / GMC Truck - Running Lean P0171 & P0174

viewers welcome back to the self-made hometown got us a 2008 Chevrolet 1500 here the money lights on this problem works in another shop Chrysler dealer I guess I can't figure out what's going on with us apparently it has some lien codes stored in it they determined it was coming from the leaky exhaust manifolds they went fix those and still has this problem just pull it up on the scans over here we're gonna look and see what coats are in it got to read the codes here we'll see what's in it and then see if we can't help this fell out indeed he is correct it's 171 174 all the way around to lean on both banks or whatever it is is affecting the entire engine let's see if we can go right into freeze-frame day to gather any information from there I left the trunk cold it's about negative 8 huh let's see so this set at 200 degrees okay add an idle looks like the mass airflow is underreporting let's see if we can find some fuel trim it's like 5 degrees outside definitely was that an idle fuel trim was enabled let's see half a tank of gas we have any fuel trim data hoping that we do okay field trim is pegged out long-term both banks short-term I'm bank one was it within fuel control but it is pretty well pegged out there short term on we've got a lot of short terms here short term bank to bank to bank one okay so it definitely was running lean the good news is at least for us is it seemed to do it even when the engines warmed up okay but it does appear that the mass airflow sensor is under reporting so that wouldn't be adding enough fuel so that's something we're gonna have to take a look at what we'll do is well back right out we will look at some data right from the get-go and we'll just make sure that it's running lean now and if it is see if we can't figure out why so let's just go right into field trim data customize it sort it out here what are we gonna want forget engine RPMs long-term make one thing too short-terms got a mass airflow sensor and think that's all we'll need let's go fire his pickup cold make all kinds of weird noise when they're cold so you can see our long term fuel trims are pegged right out there but we'll let her warm up here for a wee bit of time and see what happens so I must went in the closed-loop it's interesting to see now that our short term fuel trim is starting to make correction all right so our total here would be what 10% long term so 24-14 roughly I'm going to kind of let it warm up see what see what happens ten percents not too bad it's still running lean of course our mass airflow seems to be kind of working where it's at I'm a lot of warm-up see where this goes so it hopped inside the truck here what is it where from overhead light Noor truck still warming up I might have changed the data pit around on us here in their opening nope we're still gonna get a glare but I think we can all read the screen still so what we're gonna be interested in our mass airflow data that's calculated let me see if I can get some real nice air flow here I just poked around through some data pits while I was waiting for it to warm up there we go let's get rid of our calculated well we can leave it on the screen anyways let's see seems to be about right usually your grants per second is about the displacement of the engine you own 5.3 engine should be oh wow tell us about 5.3 grams per second so that's close enough that's not gonna skew our fuel trims 20 whatever six is almost 30 percent total okay so what I want to do is rub it up if we rub it up and we reduce manifold vacuum that's gonna tell us are we dealing with a vacuum leak or lack of fuel so if our fuel trims numbers get better hold her up about 2,000 rpms and look at that look at our fuel trims or what I would consider perfect you know add them together add them together we're close to zero that's what we would want low manifold vacuum high manifold vacuum I think we're dealing with a vacuum leak get her too hot let's see what we can find Kendra Natalie over here let the dogs bark sometimes one thing I hate seeing an aftermarket mass airflow silicone together with a cheap aftermarket air intake just have any extra nipples hanging off it that aren't hooked up I hate these things because there's always that variable turbulent air going into the engine from aftermarket components there's really no way to rule that out short of putting the factory one back on maybe worth call him and ask him did he put that on and then create all this problems let's do a little bit more check in first even though the air flow meter did seem to work correctly oh hey that's market garbage let's see we keep going we do let's proceed all right we're gonna use the already smoke and what we're gonna do is we're not gonna spend a lot of time here because we see the aftermarket gizmo and our problem is add an idol let's take and get this hooked up I pop the filter out we're gonna go right in the end of the intake and then we're going to be using our easy and takes let's just a big diaphragm goes the nerd watching girl will pop that up oh that's not gonna work that still has a waffle plate Plan B where's my screwdriver right here we'll go plan B if we don't see any vacuum leaks we have to assume you know it's aftermarket business not trying to down the aftermarket industry but sometimes cold air intakes really messy trucks up we had a fuel delivery problem we would have seen it once the engine was revved up of course we will take it for a quick ride just to verify it all right that we should have this baby in the hole forget our smoke knowing that's got the hole plugged we really all the broken smoke that are good smoke in here make sure we got lots of smoke before we plug it in and it's kind of sticking in this homes here kind of sit down beside me set it over here sitting upright want to make sure she gets a little warmed up everything's a little chilly in the chapter [Music] this one takes a few minutes to get blowing heavy smoker plug her in there if we have a smoke show anywheres on one day to pid' we should have looked at that we didn't was feel thanked pressure because if the purge solenoid stuck open that's gonna give us a really lean code I should have looked at that what I didn't know ever I think I see a problem I don't see any smoke but I think I see a problem let's go over here and have a little gander what is that oh it was hanging off the valve cover that is gonna give us some issues right I don't see any smoke coming out of it which is interesting but isn't that a vent tube it's got to be the vent for the valve cover [Music] that would have went into the factory air box it's gonna be a lot of pyrin air and it's the other one so there's one back of that valve cover goes around to the intake so that's probably the PCV system and then this one that went down there that should be that should be the fresh air side right I'm thinking about this right I am it should be oh yeah smoke coming that's something let me get a flashlight so I can see where all this is coming from not smoke where there's smoke there's fire there vacuum leak in this case well we got back here we have back here where the brake booster goes in she's smoking like a freight train Iran that so can you guys sit in the mirror that little red ring that's like a almost like a little sharkbite fitting where the brake booster hose goes in so that's a massive vacuum leak all right so that's coming from back there and then we set that also when we look at what we saw up first our other side of the PCV what's down there I'm not real good at blowing but you guys get the gist she's smoking out there so that's a massive back it looks like a half an inch hole that can leak we got to pick our battles here is it gonna be that one or is it gonna be this one the words are gonna be a combination thereof let me see if I can wiggle that little guy in there more maybe that one seals up under vacuum I don't know that's a pretty big leak that was each problem one solve this thing wasn't done it wasn't clicked in all the way now look at it I reach back there I'm gonna be able to see it let me get some more light back there again yeah see you can't see that red ring on it now I was trying to get it you got to push in on the red ring to disconnect it and I was trying to get it out and I just wiggled it a little more and it clicked in all the way so that leak is sealed our dilemma is because this is not the right air intake for this truck is we don't know what to do with this hose so we can't just block it off otherwise they'll be an insane amount of vacuum in the crankcase that host technically we need to have a hose that goes to this the main green we need and I don't feel any anything on it today what can we do what can we do so here's the plan I took the little rubber elbow off down here where it comes out of the valve cover and it's just a 3/8 elbow of course it's full of gobbledygook let's get some 3/8 hose hook this the smoker these things are fantastic to have around the shop if you guys don't have one redline makes them it's called the EZ intake makes life well you know easy for your life but at least the smoking part loosen this clamp back up all right know what I'm thinking is that we take something like this this is just a little three it's plastic elbow we Waller out a hole in here we epoxy this little guy in there and then we hook our fresh air hose back to where it needs to be so it's not sucking all that Peyer there all right you guys know how bad pirates are especially the ones on the Caribbean and I think if we just go right over here we can just you know where you guys can't see just we'll make a little loop that comes up and goes right into this sucker why don't we do that let's say bought a net the Mean Green doesn't come with it so we're gonna go right on this elbow it's gonna be pretty much directly above it let me just hold my hair we're gonna mark it with grease not really right on that seam right on this elbow let me get a drill well drill that epoxy I get some hose and we're done I think that was seems like I would have marked it at this point definite spot I marked it with my knife made a little X on it let's water it out you know you're gonna snag him waiting for em like a tiger a thing gonna be sweet now I got to see if I have some kind of epoxy that should be enough room I got some homes slip that upon she gonna be tired when sticking out if someone gets stuck no that's gonna help hopefully we can epoxy it's solid enough wish I had some kind of plastic welding device mmm if we can epoxy it just like that she'll stay oh good reach my hand in there hmm what I have to do probably what he would have done it's cut the barb off this drilled the hole little smaller so it was a super tight fit big dong I didn't even think problem number two I don't have any epoxy kick now but I do have some jb weld I'll mix it up here it says it bonds plastic aluminum steel titanium diamond in under four minutes with a weld like bond brand give it a go if it doesn't work and it just doesn't bind to the plastic I won't get some plastic epoxy resin stuff mix this up good so that's professional grade we're doing a semi-professional repair thank you that real I'm good in the Jerry reading Department but I think we'll just stick it under the lip here wind it around there make sure we have a good coating for maximum bondage okay I think we do that something's gonna be real hard for me to not fiddle with that for the next 10 minutes get it up on them so I'll make sure we got a pressed good all the way around it know if it's gonna be a long-term fix or he's gonna get the appropriate air intake but this is at least gonna prove our fix because we'll be able to take it for a shake this thing's pretty pretty porous so hopefully hopefully it bonds well to it we could add a little black paint to in a sticker that definitely might help I know how much experience of jb weld I don't even know why I have this here it was brand-new that's you know it's been on that shelf for a couple years so hopefully it's good I'm probably filled with too much already okay all right it's on don't touch it just walk away I'll get it set where it's gonna stay walk away I need to learn how to read I wrote my cookie it said four to six minutes I thought allow four to six hours or overnight 15 hours well I ain't gonna happen we're going to go to Plan C I don't want playing around right now but won't have four to six hours written gone on Napper get some epoxy one hour later Permatex plastic welder got it from the Napper I don't know how the lid goes back on it doesn't seem to oh yeah it doesn't click on no it doesn't click on well it'll probably dry out before we ever need it again ever or I'll put some tape on it it says plastic welder 5 minutes 10 minutes something like that 24 hours fully cured will not bond with polyethylene or polypropylene plastics I'm not a plastics kind of sewer so I can't tell you the difference between one of them next but I did mix it up and stuck it on there and it feels nice and hard plastic II know it's been I don't know maybe an hour so we're gonna give it the old the old go i cooped up a hose I'm just gonna hold those cuz I don't want to snap it off wait'll Adam I'll slipper on down here I actually I think I gotta slip in here first work that are on there be at least just got to be able to touch our concept right it's only temporary unless it works throughout the body here hook it up side oh yeah plastic still holding strong let's push the vinyl away all right air leaks should be resolving you put the engine cover back huh well start it up well clear the codes because we want to watch our fuel trims automatically correct turn our key on we're gonna have to reflect our data fill it one another feature it's not so handy on this is like the launch it will save the ones that you selected so we'll get coolant temp engine speed what do we want here what loop status fuel trim mass airflow and then we want our short-term that spark as far as baby up take a few minutes bath wait for it to hit closed loop and then we should see a drastic change which we are our short term fuel trim should start compensating for our long term we can see meg 11 negative 12 I'm expecting it may be negative 20 ish and that's how we know we have it fixed negative 24 it would be absolutely perfect to see so it's making huge Corrections right now what we'll do is we'll let it compensate on its own once the short term fuel trims stay it you know negative 20 or wherever they're gonna stay once our fuel trim learn is enabled our long term will come back down so this is why it's important not to clear the codes off the bat this tells us 100% we have this truck fixed you know beyond a shadow of a doubt so what we can do now is we can back back out yeah trucks gonna start running kind of cruddy I'm thinking I think we can just we can enable its learn let's see if it allows us to select the data that we want it typically doesn't but we'll see in this case it does thankfully you don't get a feel trim learn is already being enabled and it looks like we've already made corrections will pop back into our regular data to see if that's case we just got impatient it should have waited and then at this point you can you know clear the codes or just drive the kook drive truck to light goes out and it's already made the correction so yeah the the learn already enabled we didn't have to manually turn it on and we can see your field trims an absolutely perfect world would be zero general rule very general rule plus or minus ten percent you start looking for a problem I try to move around plus a minus eight percent most cars will hang very very close to zero percent and we can see our long term you know I'm bank to is minus two percent and then almost one percent on bank one and we can see our mass airflow is about about a gram per second higher than it was so that's good to know [Music] rev it up here and we're still good bring her back to an idle about 6 grams per second fuel trims are gonna correct as it goes into different learned or different fuel cell blocks you know it's gonna learn each time so at this point I'm comfortable clearing the check engine light calling this a fixed course I'll show the feller what I did in case he wants to do something different I have no idea how the epoxy is gonna react and cold weather hot weather or long term heat vibration all that stuff looking back what I might have done is I might have run a tap I'm sorry I died over top of that nipple and tapped it let's say 7/16 course red and then drilled and tapped the pipe and then threaded it in with some epoxy that give it a little bit more of a bite bite I'm very hesitant to put something inside the tube for sure you know I don't want something coming undone and you know the engine eats it I'm gonna take the truck for a drive just to be sure but we haven't fixed it's confirmed I'm happy if you're happy everybody happy and then these are the fuel trim themselves I was talking about it should be just a number yeah long-terms 1.6 on both banks fuel trim cell number six you know there's I don't know how many different fuel trim cell blocks there are but depending on engine load all that stuff it changes like here if we rev it up it's gonna go into a different fuel trim cell I think well it didn't change oh yeah I didn't you know went to field trim cell number 14 so and then it's gonna learn the value for each cell each engine load each throttle input that's easiest way I can explain that to you so alright that's it we fixed it we're good alright folks that's this Chevrolet lives to die another day and now he'll be able to get a sticker device yeah there's no inspection sticker on it you just gonna have to drive it run through a drive cycle and then he can slap the sticker on it at his shop I assume so when you're looking at fuel trends if your fuel trims are off on an idle calling for more fuel lean condition always increase the rpm to decrease manifold vacuum and that's going to tell you right away is it a vacuum leak now if our fuel trims numbers stayed negative when we increase the RPM now we're not looking at a vacuum leak we're looking at you know fuel delivery fuel delivery mostly all I can think of right off hand you know mass airflow input something like that something that's gonna skew it so that's always a quick and dirty test you want to check fuel delivery go down the road watch your o2 sensors data put it right to the rug put it in power enrichment mode if your o2 sensors all go high you know 900 millivolts you know at that point you almost don't even have to check fuel pressure anything can you know fuel delivery is good but we saw when we did it we raised the RPM field trim got pretty good and the only thing that changes is engine vacuum so we that's how we knew to go out for vacuum leak we found the brake booster bit and then of course you know the fresh air side of the PCV system which has to draw air through the mass airflow otherwise it's you know not accounted for that's it just too pumped up aftermarket green weeny gizmo thing go down in the comment box leave your questions comments criticisms down there and tell me how you would have fixed it and when you're down there subscribe ring that bell like Scotty would say and just remember yours if I can do it you can do it thanks for watching [Music]

Channel: South Main Auto LLC

Views: 599,271

Keywords: p0171, p0174, chevy, p0171 p0174, lean, code p0171, lean codes p0171 & p0174, p0171 system too lean bank 1 chevy, check engine light, tahoe intermittent p0171 p0174, how to fix a p0171 or p0174, lean codes p0171 & p0174 - diagnosed with scannerdanner, p0171 system too lean bank 1, truck, p0171 & p0174 codes, chevy equinox code p0171, check engine p0174, p0172, 2006 chevy blazer p0171, lean code p0174

Id: 3BquA8x4LMU

Length: 31min 29sec (1889 seconds)

Published: Wed Feb 06 2019