Misfire - GM Active Fuel Management Deletes Itself - 2015 Silverado

[Music] would it be redundant to say that i have a broken chevy in the shop you guys tell me this is a 2015 silverado it has a 5.3 liter v8 and it has a dead miss on cylinder number seven it also has a pretty distinct ticking noise kinda sounds like a time bomb my spidey sense tells me that those two things may be related the customer replaced the spark plugs to no avail i have confirmed that it has spark on number seven the spark plug is wet indicating that it has fuel on number seven and it also has compression but i think a simple compression test may not be telling us the whole story so let's get into it see if we can figure it out i learned from my last misfire video that there's a lot of confusion about the cylinder layout this is a gm number one cylinder is here at the front left number eight cylinder is yonder at the right rear it goes one two three four five six seven eight so number seven cylinder is that guy back there i made a whole short about this cylinder layout concept then i had a bunch of chuckleheads telling me i don't know my left from my right so just to clarify that when it comes to anything automotive the left and right is as you're sitting in the driver's seat looking forward that's the left side even though it's on the right side of your screen well i suspect that this truck has a problem with the active fuel management system [Applause] probably a collapsed lifter this could be that ticking sound that we hear all right we're going to pull the plug out [Music] [Applause] i guess the best way to confirm a collapsed lifter would be to pull the valve cover off and just do a visual inspection but in lieu of that we're going to try to do some fancy stuff with the picoscope i've got a pressure transducer installed in the number seven spark plug hole i also have a secondary ignition probe on the number seven spark plug lead we're gonna roll the scope we'll crank it over in clear flood mode and we'll just see what we see [Laughter] this is a picture of what the in cylinder waveform should look like so you got a peak here that's your top dead center compression goes up to about 180 psi then you pull a small vacuum before the exhaust valve opens that has to do with scavenging and then basically zero pressure during exhaust then it pulls a vacuum here again while it's sucking air in and then you go back into compression we have that but the problem is this compression peak right here about 27 psi gets even worse the longer we crank it gets down to about 14 psi so that's no good that is not enough compression to run i would say that's plenty of evidence to go ahead and pull the valve cover off hopefully we can confirm that it is a collapsed lifter if it's not a collapse lifter then at least we have the valve cover off we can do a leak down test and see see where the problem may be [Applause] [Applause] so [Applause] [Applause] [Laughter] [Music] yeah that'll do it what a bummer trucks only got 140 000 miles on it's pretty clean otherwise things been pretty well taken care of but yeah didn't stop it from having some major problems intake's got to come off the cylinder head's got to come off if it needs a camshaft that's even worse i think book time is like 12 hours to do the lifter and then if you do the camshaft it's like 20 hours but of course gm has to take a cue from the chrysler playbook put a freaking safety lock on every single connector and then they make it so you can't get to that connector why gm why would you do that i mean is there a big like problem with a rampant connector self unplugging come on son of a we all know i know nothing about whatever you just said so i can't really answer that purge valve what else you can do besides break the locks um try not to break the locks or poke your or poke your finger language all right i'll tell you how we're going to fix that silver lock try and find it and i still can't get it off there stupid everything's got one every coil connector every injector connector well it's probably not the water temperature sensor what are they going to do i mean the thing could explode at any minute if the water temperature sensor unplugs what's up i was gonna do the oil change okay so i'm gonna move that equinox yep i got it you gotta move that tool box because it probably won't fit past that got it is that locked yes it's light and nimble i don't know what you're complaining about where you going with that thing [Music] are you on the struggle bus over here well i tried pulling it and then all my trains kicked in and it's like oh don't pull you need to push you don't want to hurt your back and then i'm like well i can't steer it and okay well so the question is where are you going with it i just was trying to move it like half an inch over and now i made it like i'll put it this way it used to be right here should i put down the camera and offer some assistance yeah you're learning about gravity to our floor subsidence hook your sled dog up to it my sled dog is too busy trying to help me success now you got to fold the arms back in before you yeah you got it she's got a pup don't worry so that is the stupidest thing i think i've ever seen [Applause] so [Applause] okay well that should be pretty close to top dead center cylinder one yay [Applause] um [Music] okay oh no no [Applause] [Applause] oh gm says those these lines are not reusable they must be replaced i guess the bubble flare collapses too much i don't know well if we had some head bolts out probably get that cylinder head off couldn't we [Music] so that sucks well i think we're going to take that manifold clear out of there i was starting to get nervous since we hadn't got the torch out yet come on come on so it sucks you can't really drain the coolant out of the block the lower radiator hose is right here it's actually above the cylinder head okay i've got a couple grounds [Applause] so oh why don't you want to come out of there mmm crap standby man that's the loudest fly i've ever heard all right time has passed and progress has been made well i'm no expert but one of these does not look like the others that right there is the number seven intake lifter and it is frozen in a collapsed state so that is our problem i think when we last left off i was trying to yank that guy out i believe when they collapsed they're designed to expand a little bit so that they don't float around in the bore and in the bulletin service bulletin gm says just grab it with some vice grips and pry it out of there so that's what i did not a big deal really the hardest part of this job is dealing with the injectors this is a gdi engine gasoline direct injected and as part of this procedure we have to replace this afm manifold and to get that off we have to pull the injectors on the right side head it is not fun those things are are wedged down in there these wells have been filled with salt and corrosion and god knows what it's borderline easier just to pull the other head than to deal with those injectors anyway this is pretty much cleaned up and ready to go back together the good news is other than being collapsed this lifter is in good shape the roller is good the bore is good and more importantly the cam journal is good so if this roller fails it can chew up the cam and that basically turns this let's say twenty five hundred dollar misfire into a six thousand dollar misfire we would have to pull the other head the timing cover probably the radiator and all the associated stuff in front of that to replace that camshaft that would not be a fun time i've got the head the valve cover and the exhaust manifold cleaned up all the gasket surfaces are cleaned these are ready to install we also have parts right from the gm steelership there's an injector seal kit intake manifold gaskets donut gasket plastic lifter guides new head bolts including the one weird socket head bolt there's the gasket for the gdi fuel pump valve cover gasket head gasket exhaust manifold gasket and then the big one is this kind of kit here i ordered all these parts based on the tsb the service bulletin and they say to replace the afm manifold i'm not exactly sure why but gm really wants you to replace this to the point that they won't even sell you the afm lifters unless you buy this whole kit that has the fuel pipes and the manifold that's the lifters right there and they would not sell them to me separately i had to buy this whole kit anyway everybody always wants part numbers i'm not going to give you part numbers just go to the dealership give them your vin number tell them what you want expect to pay around a thousand bucks maybe 1100 bucks for all these parts if you're just walking in off the street but i would not go after market on something like this just stick with oem parts there is a tool you can buy to remove these injectors it threads in where the bolts go then it has these j-bolts that hook underneath the rail and you crank down on some nuts and supposed to pull the pull the injectors up i'm not sure how well that works what i did was i just i hosed them down with some penetrating oil just filled the wells right up then i left them overnight and then i used two pry bars this little guy here will come in from behind and i can hook right underneath of the clip that holds the rail to the injector and then the other bar i can come in underneath of the rail itself and then just try to work the two bars together and on mine the first cylinder number one or number two number two it started coming out first and then this one at the back the two in the middle were the hardest but yeah just slowly working them and they finally finally pulled out i have seen pictures online of bent fuel rails from people trying to get them out so yeah i mean it is what it is it's got to come apart so i guess if you break something it's it's going to have to be replaced we need to install new seals in the injectors there's some special tools to do this of course i don't have them so we're going to try to get by without them i did this one as a proof of concept and it seemed seemed viable so let's see what happens here we got to get this clip off there we go you can see the marks here where i pry it up on that fuel rail i mean i don't know what else you can do you got to just get physical with it would have been nice if they would have designed it so you could get that manifold off without pulling the injectors but i guess that's asking too much okay so we got an o-ring and a backup ring nice thing about fuel though everything's clean and service data says just use engine oil to lubricate these comes with a new clip which we will use there we go let's make sure the tabs locked in back here all right now the real fun so there's a dust seal here ours did not have the dust seal originally but it says just go ahead and install it then there's two teflon seals that we have to fit down on the shaft of that injector and there's a special set of tools you can buy it's basically a cone that expands that seal lets it fit over the end and then once it's on it's kind of stretched and deformed and there's a special tool to to resize it to squish it back down we don't have those tools so what we're going to do is just slip it over the end of a center punch the seal and stretch it and you're not going to tear it these things are really tough so stretch it out you know way past the point where you feel comfortable let it sit for a few few seconds and then hopefully it'll be stretched enough we can get it over there we go there's one there's two okay now the problem is they're too loose right so we have to compress them back down just like seals and hydraulic cylinders if you leave them long enough they should eventually return to their normal size but we're going to accelerate the process there's a piece of fuel line with the hose clamp just going to slip it over crank that down all right all right a couple minutes later i think that'll work [Applause] [Music] we're supposed to torque it in two passes once at 11 foot pounds and once at 22. oh crap looks like we forgot the bracket so okay work that to 18 foot pounds which isn't very much service data says not to lubricate those lower seals when you install the fuel rail [Applause] it also says to install the fuel rail the right direction well i sure hope that worked can't see the seals so i have no idea if i if i got that right or not 18 foot pounds again and they want you to put loctite on those bolts [Applause] all right very neat now we're in deep now all right time for the fun part so i've got the two non-afm lifters installed in the new guide everything's keyed correctly i believe so that should just slip right down inside there that should be it 106 inch pounds so so [Applause] [Applause] okay the sequence is 59 foot pounds start in the middle work your way towards the outside [Applause] so so [Applause] [Applause] there is no real valve adjustment it's all kind of built into the the clearances when they make the engine pretty typical for your modern american engine we're supposed to do i'm not sure which one we're supposed to do i think we're supposed to do exhaust on three which would be this one [Applause] tighten it and then exhaust on four and five which would be this one here okay intake on seven okay now we gotta turn it 180 degrees so we're gonna be both on number one [Applause] this guy here okay five [Music] right there okay so we should have them all not sure why they make you go through all that all right we gotta torque those 22 foot pounds [Applause] well if we've done this correctly we should have valves moving on every cylinder [Applause] hey we got the one back that we were missing that's good [Applause] okay [Applause] [Applause] [Applause] [Applause] so [Applause] [Music] and we're out of battery okay i'm sure there's a torque spec for that knows what it is cross your fingers folks [Music] i think we're ready to fire it up everything's back together except for the inner fender it's mostly full of coolant we're gonna run it for a little bit and then i'll go ahead and change the oil assuming everything's okay [Music] sounds like all eight yeah i left the map sensor unplugged so let's uh let's clear that out okay time for a drive well i don't know what's going on i'm getting misfires on cylinder number eight under load [Music] i really hope we didn't screw up that injector [Music] yeah it's not doing anything that sucks all right back to the shop my patience is all used up we've got a misfire cylinder number eight it runs fine at idle it runs fine with no load as soon as you put a load on it or try to drive it number eight cylinder just falls on its face it has good spark it has a new spark plug i tried swapping the wires that is not the problem the only thing that we changed or messed with is the injector i ran an injector balance test these are the results so it's actually pretty easy to do on a gdi engine because it has a rail pressure sensor so all it does is it shuts off each injector one at a time and then it measures how much the rail pressure increases when that injector is not firing and the numbers they're kind of all over the place i think what's happening is the left bank here is how it should be the right bank these numbers are higher than normal because they're trying to compensate for number eight cylinder it's only at 4.7 these numbers are in psi but the the units are kind of irrelevant it's just the difference between them that matters so yeah obviously something's going on here anyway i bought a new injector that's it right there we're going to install it along with new seals for the other three injectors yeah let's put it in hope for the best the really crappy part is the fuel lines these are one time use so even though they've only been on there for let's say 10 minutes of running we have to toss them and replace them and i was able to get one of them but the other one i could not get through gm so yeah let's hope for the best uh this is what i was worried about come on look at the quality of that plating why are they plated the gm line is stainless steel yeah there's no way i'm going to put that on what a bunch of crap so is this crappy poorly plated dormant part a bigger risk than reinstalling the slightly used part i really don't know man i'm trying to think about the last time i worked on an actual car four bolt wheels even anyway we're back together i chose not to install this shady dorman fuel line or my new other fuel line i put the old ones back on we're gonna run it like that for now until i can get the correct fuel line from the gm mothership hopefully they'll have it for me soon i think it'll be safe enough to run it that way for for a little while you've got to be kidding me now we got a dead miss on cylinder six it was fine before now it's not fine ah if i had the dynamite i would blow this thing straight to hell i just i don't know what to say about this what am i doing wrong it's the same as it was with number eight but now it's on number six runs fine at idle it's fine under no load or moderate load you step on it and it just falls apart i just don't know what to do replace all four injectors and the rail is there something floating around in there that's blocking the injectors i just i don't know i guess we'll go back to the shop call the customer again tell him his truck's broken again and we'll wait for more parts see it's fine right now there it is i just don't know [Applause] it's fixed it's done it's gone it's out of here i've had 27 hours to kind of calm down and collect myself that was not fun not even a little bit if you weren't following along the initial misfire was on cylinder number seven that's on bank one that was caused by a collapse lifter we pulled the head we replaced the lifter that really wasn't a problem the problem is once we got it back together we had a new misfire on cylinder number eight that's on bank two and all i can figure is that somehow i damaged the injectors when i pulled them out i mean they came out hard but i thought i thought i was being careful not to bend them or tweak them or do anything crazy but apparently i was wrong i replaced the number eight injector we took it for a test drive it seemed to be going well and then about two miles into that test drive we got a misfire on cylinder number six and i was ready to push it off a cliff cylinder six is also on bank two so in the end i put the parts cannon on full auto and i replaced all four injectors on bank two i also replaced both the fuel lines and that did the trick yeah i ended up having to use that crappy dorman fuel line i called six dealerships within a reasonable driving distance that was supposed to have this fuel line in stock three of them either no longer had it in stock or it was already sold to a customer the other three they either had they had it already booked for a job or they just refused to sell it to me because they don't know when they're gonna be able to get one so the the parts guy at the last dealership he told me they use the doorman part all the time because they they don't know when they're gonna be able to get them from gm so what i ended up doing was just taking some very fine sandpaper and polishing this flared end just to get those whatever they were pits out of the plating and i was pretty happy with it when i got done so that that wasn't that big of a deal yeah i guess all's well that ends well we'll put that into our our knowledge bank our bank of very hard earned knowledge if the injectors come out hard plan on replacing them i don't know if i bent them or tweaked them or did something to the the coil electronically i really have no idea but uh yeah they're no good okay that's it folks thanks for watching and i'll see you next time

Channel: Watch Wes Work

Views: 672,171

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Id: fnsFjwpf-zo

Length: 48min 15sec (2895 seconds)

Published: Sun Aug 14 2022