Chevy thunder looks like a old four or five. Maybe 06 chevrolet, it's the 1500. I just dropped her off brought her from one of the other shops. He said he took it there.

Well, let me tell you the story. What he told me is he took it to the other shop, we'll call it uh they uh his complaint. Is the engine light's on and sounds like a misfire lights on lights flashing. He said they did a number three coil and then a number four coil, and then they seen that the wires were braided.

So this is gon na, be a coil near plug from the sound of it. So a coil and a spark plug wire and then they did the wires because the wires were braided and then you know still has the issue of this flashing light and the skip and then they uh. He was told at that point once the coils were changed. The only thing they can do is change the sensor, not sure which one i assume maybe like a crank sensor, and then they did that and then he still has a problem.

So then they told him major electrical you're gon na have to go to this guy. In downtown avica - and here he is so - we need to figure out what's going on with it, so we'll fire it up here, she's, definitely skipping, let's put it in drive. Funny thing is, though, i've drove me a lot of shiverways, and this does not feel like. No contribution, let's power break it slightly, shall we ah, i could be wrong that might be a totally dead hole yeah.

It's got a pretty good hitch in this video. Let's have a little listen as we crank it over. That's always a clue so wide open throttle. We're going to try to crank it sounds pretty normal uh, but that can be deceptive even to the trained ear, not that i've trained my ears.

But you know what i mean. So, let's pull it in and the reason that we do that crank, no start there. Where we just whizz it over is because we want to hear, does she sound like she got a dead hole so um, let's get a scan tool on it. Let's see what cylinder it tells us is misfiring, but it's weird at an idle.

It feels more low contribution than no contribution. Why is that important to note simply because you know that could be engine mechanical, you know. Do we have a loss of compression, but not all of the compression like let's say, we've got 80 pounds compression uh, so it still starts runs almost fires, but not quite. Whereas if we had no compression or no spark or no fuel, then we usually have what we would consider a dead hole where it's you know hard misfire at night.

Oh, you know truck shakes, sometimes with a v8, though that can be deceptive um, because you got seven other little guys making up for the one little guy. That's not anyhow enough talk enough guessing, let's get a scan tool and figure. This baby out dang down 23 should have plugged her in last night and my updates are out really slacking here folks, big time i need to renew my sub. I just haven't had time yet we're gon na let this little guy go through and uh do a system scan as we would uh.

I don't think so. Uh too many questions mm-hmm! Oh my gosh. What's it want my blood type? I don't know. I have a little gander here and i do see the number two is brand new.

You see, i just work. We rhyme that one up uh, let's see what we got over here. Oh yeah, that's not number two, you didn't die start chevy, guys number three and number four on this side is brandy, new brandy, new wires, just like they said and as far as the sensors yeah we'd have to call underneath to see if it did get a Crank sensor, however, the all-tell is now booted survey, says random, cylinder, misfire and a large evaporative leak. Okay, this is the one we're concerned with today.

Let's hop into our misfire data just for poop and laughter, let's fire it up cylinder three and four is what it tells us cylinder 4 has the most accumulation on it according to the history. So that's interesting, just giving her a little look-see here, like i say, she's, not not shaking too bad fellas we need to find out is cylinder 4. Really. Our culprit, it appears to be here, appears to be more four than three.

I don't know what the firing order is on these new chevys uh i'd be curious to know if three and four next to each other, therefore giving us some false falsies on number three: let's go put it in gear and see if that cleans it up a Bit just because it doesn't feel like a multiple cylinder misfired, let's put her in the drive now, let's look at misfire data. Definitely more steady on four i'm going to give her a little throttle a little power break. Let me put it reverse case. The brake lines below give her a little bit of throttle and we can see there were steady misfire at number four.

So it doesn't surprise me to see it registering three and four with no load. Okay, so we're going to blame number four. However, we need to verify that so we want to go. Uh kill an injector here.

I don't know where, where that's at oops click happy jerk um, nothing, there maybe special functions. We should be able to shut off an injector blah blah blah. Here we go. Let's see okay, so what we're gon na do.

Let me let me close the door here in case we do blow a brake line. I don't want to have to put a door on this piece of junk. Let's see so i'm gon na power break it here. A little bit, i didn't feel any change there.

What let me kill number one. Oh yeah, big change, i don't know if i can just kill one and it kills turns the other one back on. You know what i'm saying if i go, two dead one dead. Three dead, so they're all enabled, but when i kill four there is absolutely no change.

Don't worry about the day, we're not looking at any data, we're just going with what we feel and what we hear yep. So number four is. Definitely the culprit number three big change. You know we probably could see it in fuel trim.

I don't know i got ta. Show you something. Let's see we'll kill number three yeah. I say our fuel trim should should start to increase number four, because anytime, you have a dead hole.

Now that cylinder is just pumping air, so uh um, look at this see our fuel trim for cylinder for bank 2 is really high. I mean this tells us. We have a misfire. Does that mean it's fuel related? I can't really attest to that.

There's lots of controversy on that. In my opinion, the cylinder's pumping air - it's definitely cylinder four, let's find out. Why so does that make sense to you seeing that the fuel trim numbers are really high on this bank? So this is bank two uh, because we have cylinders. You know two, four, six and eight over here.

I don't know the firing order, but i know that much uh. So when you have a cylinder, that's not firing. There's no combustion. The oxygen sensor doesn't see it.

Therefore, it sees it as pumping air and and sees that whole bank is lean and then the fuel trims are high for that bank. Now i know uh some guys in a watch or some guys see they'll put their life on the line and say that 100 is fuel related yeah. It's a fuel related misfire, because your field trip numbers are high. I would have to disagree because if i pull a spark plug wire off that side over there, even though the injector is still working, that cylinder is now pumping air and it drives the fuel numbers high on a speed density engine on one that runs with a Mass airflow not a speed density engine, a mass airflow engine; rather so i never really banked my whole diagnosis on what type of misfire it is based on fuel trim alone.

I look at it. I take it in consideration and then i move on with my light. So what we need to know now is number four you know: do we have spark, do we have a good spark plug? Do we have compression? You know, is this mechanical? Is this ignition related or is it fuel related brand new coil brand new wire doesn't mean they're good sounds like they've been chasing this thing around, so all i want to do. Uh is quickly verify you know.

Do we have spark is the spark making it to the plug? Is it sparking if it is great? Let's move on and just like, if you're in the business of skinning cats uh there's more than one way to do that and then what we're gon na do is we're going old school spark plug tester mother, that's hot! Come on danny uh! Just simply because i can have this plug wear off uh faster than i can get out of scope and turn it on. So what we want to know is, is this coil firing and we're just going to hook this to something and then we're going to sit here, we're going to start it up see if it's firing, if it is um, the spark plugs are brand spanking new. So highly doubting that we have a bad spark plug, but we can and we're not going to interrupt our process for an assumption, because you know that whole process assumption and me and you and something to do with an a-hole and stuff like that. So, let's see, can she jump the big gap right there? Let me go fire it up.

Well, yes, sir, you leave me on the levee. Let's make that up, so we have spark out of the coil. Is it occurring at the right time? We don't know more than likely, because all the other seven spark plugs seem to be firing at the same time. So what we could do now uh, if we're so inclined to do so, is we could pull the spark plug out and say: hey? Did these guys? Just have some bad luck and get a spark plug.

That's you know carbon track down the side easily could see that on the scope. If we had a scope, we hooked it on where we could see. Are we firing inside the cylinder? Are we firing outside the cylinder? Does it appear to be a lean condition? There's a lot we could gather from secondary waveforms, and sometimes that's good to do, especially when we find out like hey this thing's just got a bad injector. Then you could take your time to hook your scope up and say: well what does this look like on a super lean, cylinder and then kind of commit that to memory and use that in your diagnostic arsenal in the future, when you get another car in that Has a misfire that let's say it's not as easy to get to the plug and wire, but you can get a scope on it.

You can look at that secondary waveform and say: hey this one's rich, this one's lean. This is firing outside the cylinder. So on and so forth, but for this purpose on this video we're going to yank the plug, have a visual inspection and then, if it looks fine, just swap it with another cylinder, misfire stays on this cylinder. We know we have spark.

We know the plug's good. Now, let's look at engine mechanical and fuel old school, so let's pop this uh plug out there. I know you can't see much, but it's just a standard plug removal. So we'll get this out because some ac delcos, i tell you what brand new out of the box.

They do, have a tendency to get some carbon tracking on them or be cracked down the porcelain. So we'll take her out she's white and shiny hotter than a banshee covered with slime. Hi luna come here. Come here, baby, hi pumpkin! What's in here baby say hi.

Here's luna! She just coming in it's the night out on the town. Take one side i just gave the plug a full cat scan and it came back good, but that's not always a good test cause. What do cats know so now come on baby, what the freak hole so typically, this is where i should just use the scope, because guess what the plug wet super attached to the spark plug down there, so we're gon na take that off now we're gon na Take our spark plug wire: this is from the number two and we'll pull it back in back in the hole, everything's pretty hot, and then we're just going to swap that plug, because we know we're not having a problem with the number two cylinder. So you see what i'm saying we'll do the old swaparoo.

It's called swaptronics, it's not as bad as triagnastics, because it is kind of like diagnostics, but it doesn't cost us anything except a little bit of time and i'm doing this solely for your education, educational purposes and as silly as it sounds uh, even though many folks In the automotive industry diagnosticians they like to be called would scoff at this approach. It is, it is an approach that a uh, you know that not only can be used in the shop, but you know a diyer can do themselves simply because these parts are all similar. The coils are the same. The plugs are the same.

The wires are the same and if you don't have access to as scotty kilmer calls them your big fancy scan tools. Then this is a approach that a guy could take um and - and sometimes even if you do have your big fancy scan tools, you can still use this approach uh simply because it works and um it's really limited by access to like and similar products on the Vehicle, you know, are the coils are real pain and the hoo-hoo to get to are the plugs that you know, son of a mother to swap around. You know stuff like that where this here, like i say, is pretty quick and it's a good eliminator and i mean you can take it as far as you know, if you had to you, know swapping injectors, but at that point it gets kind of silly. But simple stuff like this, you know the coil is a plug.

Is a wire nope? It's not ignition doesn't appear to be, could it be still yeah? But what are the odds you know head your bets baby? You guys can't see crack down here. So that's me trying to do kilmer impersonations, make sure she's locked on she locked and loaded and of course, this whole thing could go sour, because if this had old, crappy wires and the wire breaks and here's your judgment, i guess what i'm getting at fired up. Still skipping oops, we don't want to go to active tests, we'll just go right back to the live data engine data we'll go to the misfire hope. Let me power break it a little, but it looks like we're still having an issue with numeral.

Four still got the problem in number four, so there we go process of elimination. We have a pretty good idea what it's not now. This is where i could get burned by going diy-ish on it is listening to it crank over here we can have a listen again more inside, listen closely so cranking over, like that sounds pretty normal. I could get burned.

If i had my scope out - and i was looking at secondary ignition waveforms i'd boom - throw it on the uh, you know negative battery, post or positive or whichever hook up the leads. However, we want to do it. We do a relative compression test and say yep relative to each other. They all look the same in my experience, i'm gon na skip that which i shouldn't and we're going to do an injector balance test because we have our scan tool hooked up.

So what we'll do is we'll pressurize the injectors with the scan tool as a built-in injector balance test for these chevrolets and we'll turn on each injector and we'll see how much pressure it drops uh when we command those injectors on and we're gon na go right For the gusto we're not gon na do them in order we're just gon na go down that bank. We might do cylinder. You know three four and five and see if cylinder four is not flowing as much fuel as the others. That's kind of fun just had a fellow stop, then a local farmer down the road got one of these chevrolets and uh he's bleeding out his hand, pretty good and asked me to change his number seven spark plug for him because, as you know, these afm engines And the later models are complete garbage and, of course they burn oil and follow up the spark plugs and stuff, so you keep spark plugs with them and keeps changing out the number seven every six months or so, but he's a little frustrated this morning.

So i just went on the parking lot and changed his uh number seven spark plug, so we could keep driving this chevrolet. So what we're gon na do now is we're going to install this little guy, so we're going to put on our fuel pressure gauge now. I could be wrong here folks or we could be right. I think those are lyrics to a song, oh get that there and then, like i say, we're gon na turn.

The key on and the scan tool has an automated process of turning on the fuel, letting it build pressure and then turning on an injector for a given period of time or pulses, which equates to time and then we're going to see so we're at 60. Then we're going to kick it on and watch it and see how many pounds it drops per each time it kicks on. So let's do that. Let's get something right on so some people ask uh, so click fuel injector balance like oh erico.

I don't have a no. I don't have a big fancy scan tool. That's okay, because if you're doing an injector balance test, it doesn't matter because you can buy a standalone device to do that. A little injector, pulsing tool, uh, i don't know ktool - makes i have to look at my box, they're quite inexpensive and you can get them on amazon and then they're universal.

For all. You know. Electric fuel injectors like this, not gdi um, but this style electric solenoid type injector. I don't know what else to call it.

So, let's go injector number three, let's see here, so she just built up fuel that was quick a little bit better too much. Looking too much talking, so i get you, i need to do that again, uh. So when i push the injector button, it's gon na build up fuel pressure, we're going to look see where it's at record that and then watch the drop. So, let's do let's say: let's do cylinder five hit the button 48 to 34., so 48 psi to 34 psi, and that was number five.

So now we'll do number i'll. Let one build up: there's 48 to 35, so 48 to 35, and that was number one. Now, let's do our offending injector. Let's do number four just to see where that's at 48..

Nothing there's no clicking, there's no, nothing! Let's do number six 48 to 34 48 to 34 psi, and that's number six now just for grins and giggles. Let's do number four again: 48 psi. Oh injector has already been tested and unable to restart during this ignition cycle. Okay, so it won't run the test twice because it doesn't want to swap the cylinder so uh.

We have a pretty good idea, though, from watching that either that injector has some electric problems going to it or the injectors just pooched, which i would imagine if that injector was unplugged. Let's say it's open, circuited, broken power, feed or a broken control wire. I would imagine we would set an injector code like a p0204. I think that would be an injector code which we don't have.

So i assume that electrically it is there and it is. The computer sees it as having continuity through it back on the control wire. Therefore, the injector itself is probably garbage, so, let's just test that theory uh we're going to back out of here and we're going to simply just do that by starting it running it and using our test light uh or we could use a noid light. So, let's do that so busted out the old noid light set we're gon na unplug.

This injector here get our harness up out of the way, get the little blue clipper up out of the way. These things can be a real pest pot. There we go there. She is baby, so then what we could do at this point is, we could check.

Do we have power here and then do we have control pulsing control uh or we could just shove a noise light in there and fire it up and see if it blinks, which this one doesn't fit quite right and i don't want to spread the pins. So, let's just start it and see a couple things you know: do we get a code for it which that would be nice and do we have a blinky light which would be even nicer so stand by now we're gon na go to codes and we're gon Na see, hopefully, we threw an injector code. Injector control circuit po200 surprised it's not specific to that cylinder. But what do i know and we have a pulsing? I don't know if you guys can see it here, turn off the light.

Let me see what you see and we have a pulsing noise like. Can you see that i don't know you're gon na have to trust me, but we have a pulsing noid light. So that tells me you know we have the ability to fire this injector. So that's that let's uh shut this junker off so now.

What we'll do is, let's test our injector. It must have some sort of resistance through it or continuity through it um, because a lot of people right now are like oh you're, an idiot. You can't test an injector with annoyed light, blah blah blah. I understand that.

I also understand that that noid light draws about a half of an amp. These injectors probably draw about three quarters of an amp and it lit up what seems to be about normal. So calm down, it's close enough test. If we had no blinking at all, then we would be concerned so we're going to check uh the injector here i would expect probably 14 ohms or so we can always compare it to no good.

But if let's say we're, if we're higher than 15 we'll do something here or lower or higher or whatever, but let's see we checked this in jack there and the survey says: come on baby 14. ohms, 14.3 ohms. In my opinion, that is perfect and that folks is why we have no um no code for it, because that is what i would consider to be perfect. That's really good! Let's do this.

Let me turn the key on and show you something we have k-o-e-o kion engine off we're gon na pop back into our special functions. We're gon na go hit the cancel, we're gon na, go to fuel injector balance and then we're gon na go to cylinder four and we're gon na make sure that our balance test is working properly, where it fires this injector power up and then should fire bing Bing bing bing bing see how nice and bright that is. We are 100 being a shadow of a doubt making the call on a bad fuel injector. It is a mechanically stuck shut electrically.

It is perfect, therefore, we have no codes but, as we could see doing our balance test when we did that it cannot flow fuel, even though we have control to it, it will brightly light a noid light, which draws almost as much current as a fuel injector Um, that's that we could easily put a scope on that and we could see our inrush current. We could watch our ramp build up, but we would never see a panel hump in it where the injector normally would open, where we would see that mechanical movement of the fuel injector we will not see in this case. Perhaps i could show you that for you guys who are scope, users where we could have thrown a scope on that scrutinized that waveform and i would be willing to bet that we will not see mechanical movement on it. So, let's, let's do that.

Just so! Everybody's happy we'll do it right here at the injector that way, i don't have to find a fuse. Let me grab a capture here, uh and then i'll i'll see. If i can show you what's up uh we'll see if this works, we're gon na try a good cylinder we're upside down. Are we upside down a lot of interference here? Okay, let me uh, let me try to set a trigger here: uh edge, triggering okay, okay.

So we got a trigger set up uh. We need to change our time because we want to be able to see what we can see trigger's in a bad spot. Let's put our trigger up here higher, let's get a little more time. I want a little better definition here and then, let's change our scale here to one and whoa baby click on that bring her down um.

That is on a good cylinder. Let me change my time yet one more time we'll go to 500 microseconds here i was really hoping to see a more clearly defined panel opening. We can see a little sag right there, so this is as current being induced in that coil and typically, when that panel opens. When you get movement of that physical movement, we have a little reduction in current, which usually it's more of a clearly defined hump.

As you will and then, of course, the injector is on and then the injector shuts off, so i see slightly here. This may not be a good demonstration, so that's a good cylinder. Let's go to our bad one. Now this is our bad one and i cannot definitively look at that and then look you in the face and tell you that yes, i would make the call based on that waveform uh, because i'd be lying to your face.

So, there's there's not much that i can tell you there folks uh, i was hoping that was going to be a better demonstration oops. However, this is perhaps why we uh why we test things multiple ways. So that's a little frustrating hoping that was going to be better for you. I don't see a clearly defined kennel hump looking at current, usually it's more defined.

So that's a bad cylinder. That's our dead hole! This is our good hole must be. I didn't didn't zero. This little guy something's happening there.

There we go so again. That is the good one, and that is the bad one. I'm looking at the leading edge here and now, frankly, i'm not going to scrutinize it too heavily because well, we already know what's wrong. Sorry for such a poor demonstration with that, i honestly thought that we would see something more definitive with the amp clamp, but it's also a great learning opportunity because, like i say you know, we've proved the injector doesn't flow.

It's got everything it needs to make it flow um. You know it's, not engine mechanical, nothing. You know it's simply injectors receiving its commands. Coils getting saturated, you know electrically, it works it's physically stuck, so you know take that opportunity grab your scope.

You know hey. We got a known bad. We got seven known goods. Look at them.

Can i see the difference in the current flow uh with those you know, look at the secondary ignition can identify a lean cylinder like i know this cylinder is dead, it's gone, it has no fuel. What does that spark look like, and can i discern that waveform that scope pattern from a cylinder, that's firing good and then kind of, like you know, save that like this cylinder, we know for a fact. This waveform has no fuel this. This one is pumping air.

How does it look you know? Do we see this huge lean spike at the end of the burn line? You know the secondary ignition um. You know, what's that, due to the overall, you know kv spike um. Is it easier for that spark to ionize in a lean cylinder versus a rich cylinder? You know you can start to see that take some of that stuff. You learned in classes and kind of apply it like yeah.

Or do you look at it like? We? Just looked at this and been like you know, i don't know, i would have never been able to make the call. I would have never made the call looking at using this scope with this clamp in that fashion and say: yes, that is a bad injector. We could have done other tests, we could have used the scope and a pressure transducer to look at injector drop on each cylinder because even just doing what we did, we see there's a psi or two difference between a couple of them that we just tested. So lots and lots of different ways.

Like i say, if you're in this cat, skin and business, you already know it there's more than one way to do things so, but there's only one way for you to do something for me and that's for you to head to that comment section. The questions. The comments the concerns i'm gon na get an injector for this fella and you're gon na go down there and ring the bell: the insti, the facebook and just remember viewers. If i can do it, you can do it thanks for watching.