how to diagnose a misfire

 how to diagnose a misfire in engine

2003 Toyota Matrix with a check engine light on customer says it has a little idle but I don't feel Aloha - I feel rough idle and I took it our little test drive and it feels like it almost feels like an ignition coils misfiring you have to be sitting in the car to actually feel this misfire it's pretty rough and yeah check engine lights on once you start driving the check engine light starts blinking once that check Engine light starts blinking that tells you right away that that's a misfire bad enough to damage your cat so I don't want to drive it too long I just put it in the shop and what I'm gonna do right now is just scan it for codes and then depending on what code I get if I need to look at some data or some graphs or something then I'll get my snap-on scanner but if not we can try to fix it just by reading a code and doing some basic tests under the hood so let me Show you what I'm let me show you what I got on my code reader all right so I got my coal reader set up right here when I use this code reader I go straight into them I go straight into global 3 codes I don't go to vehicle specific I mean sometimes there's no need to plus this scanner like I said before only goes up to 2004 and after that it goes global anyways but this is all three matrix and right now what I want to do is just get some code and then that's gonna tell us What we need to do if we need to get the other scanner or if we can figure it out just by reading codes with this Ektron so here we go see what's in there two codes found hopefully you guys can see that good so I got a cylinder misfires number two and a cylinder misfire number two alright so p0 302 cylinder to misfire so let's go under the hood and then check some plugs or or some coils or CC do a visual inspection first and then we'll See what we can do so it's going to the hood alright so I'm gonna keep you guys focused right here I'm gonna take this cover off pick the coils off and do some swapping around then we'll go ahead and clear the codes and recheck everything so let me do that for you real quick all right anyways on these connectors you want to be real careful puzzle when you try to take them off they use it to break I'm just gonna use a little t pin So that I can fry this connector up cuz I don't want to break it I'm just gonna help it out help it up and then I can pull it out just like so so this is coil number one this is a known good coil according to me and this is number three right here so number two so what I'm gonna do right now is swap the plugs I'll put the plug from two on to one and then I'll put the coil from two one two three and this way we'll figure it out all right so that's cylinder number one Spark plug it looks pretty bad it doesn't look like they they're near let's just open the place before this right here cylinder number two so just by looking at plugs I don't think this is a problem I think this is more like an ignition coil issue so I'm gonna swap these and then I'll swap coils so that quote is going onto cylinder three the spark plug from Senator - it's going on to cylinder 1 will clear codes and recheck everything And see where the misfire follows  all right so we couldn't back in here you still got that cylinder to misfire turn our key and what I'm gonna do a real quick is clear the codes so erase my coats here and then I'm gonna start it up and we'll see where that misfired go my guess is gonna follow the coil but I'm still gonna recommend spark looks Like I showed you so arranged diagnostic results yes please do command sent and just to be sure I'll go back and read the codes no faults okay let me start up the car and this is what I'm gonna do I don't need to go drive it I can feel a slight miss right now but what I'm gonna do is put a little bit of load on the engine I'll put it in reverse and I don't know if you guys can hear that but that really puts put stress on the coil and On the plugs and that'll don't make the misfire more evidence so what I'm doing right now is just waiting give it a couple seconds move it back and forth a little bit you don't got to go drive it just shift and put it back and drive and move the car forward and after like a minute you can join it what you can do is cycle the key on and off because usually it takes a couple key cycles for the computer to set a code so I'll keep doing that put it on Reverse oh yeah that has a dead misfire right there like I said before guys usually when you put it under load that is a dead giveaway of an ignition coil and plus these cause on these Toyota Matrix Corollas they're pretty common failures so that's what I'm looking at right now and and then you guys can also see it on the on the exhaust you can see the the inconsistent in the puffs so to speak so what I'm gonna do put it back in park and then I'll recheck for coals Just to see if there's anything here so I got the key on and see if there's any code sometimes there's pending codes and it'll come on right away so let's see if we got anything here with codes I here we go all right so let's see if we got anything no faults yet all right so got a key Primus drive what I'm gonna do is actually a brake torque it so I'll keep my left foot on the brake you just drove it up a little bit when my right while I was Still in drive but you don't want to do that for too long put it in reverse rev it alright that worked there we go we got a let's see one code found and that is cylinder three and that is exactly where our coil went so this car needs an ignition coil and that's gonna fix the misfire but I'm still recommending plugs like I said so this cars getting spark plugs one ignition coil and then we can Get it on its way so it's that easy guys senator three misfire ignition coil coming a quick cylinder misfire figured out in about ten minutes just by swapping some parts not all the time it's it's it's not necessary to be putting all your scanners and your scopes and your secondary testers and whatnot to figure out a misfire obviously if the car if the coils are not accessible like on this one then obviously yeah it's gonna be little bit Harder but if you have like this if you have something like this that's a four cylinder where everything is easily accessible to you go ahead and swap parts there's nothing wrong with it so it really doesn't matter how you go about it as long as you can figure out and solve the customers problems as long as you can correct the issue then there's no wrong way to go about it so I'm gonna leave it here this cars getting four plugs and one ignition coil And we're gonna send it on its way and that's it for the video homies so I'll see you guys on the next one drop a like if you guys like this leave me a comment below and then subscribe if you haven't so that's it it's not one more thing I want to point out to you guys and here's something to note if you look at that cylinder one ignition coil it's a Toyota part cylinder - which was on cylinder three years of Toyota part a coil that is misfiring is an aftermarket part you Could see it has no brand on it there's nothing on there cylinder four is a Toyota part also so one two and for our Toyota coils this one is an aftermarket coil it's already been changed and it's bad again so what does that say about aftermarket parts then it change the plugs change that one coil but I'm gonna hire at the man oh we parts so that's it guys see you on the next article

  As you guys can see I'm also doing a valve cover gasket because one of the grommets was actually leaking oil into this coil I don't know if it went bad because it's an aftermarket coil or because the oil was leaking into that but since I saw oil in there the valve cover has to be done so that's what I'm doing right now and we're gonna get back on it and keep working here [Music] all right so we're gonna be going with a Denso o e this looks like a pretty good quality code plus Enzo is yo e for the I think it's the only manufacturer for coils and then for the plugs, we're going to be going with some NGK Iridium so imma put these in put that in and this car should be running like a champ after this 

thank you for reading my blogs kindly share