A misfire and how to gain Automotive knowledge

A misfire and how to gain Automotive knowledge


[Music] velcome be common given welcome to another episode of diagnose dan today working on this 2005 mazda 5 with a 1.8 liter four-cylinder engine the customer complaint is it has got a loss of power the check engine light is flickering and according to the customer is not running on all 4 cylinders so let’s diagnose this together now before we start diagnosing this Mazda there’s something else I need to address I’m getting a lot of questions from you guys lately on Dan how can I gain more knowledge how can I learn more now as you guys know that’s all this channel is about learning more so there’s something that got me very very excited I just need to share with you guys now a couple of months ago I got to learn about this company called electrode electrode is a company that’s developing automotive educational software for schools now they also made it available for individuals like you and me now I’ve been working with their software for a couple of weeks now and I’ve got to tell you guys each time I’m using it I’m getting more and more excited and I was thinking hey I just have to share this with you guys on my channel now I’m very excited about this software and I will leave a link in the description of this video how to buy this software and I will promise you guys for the amount of knowledge you will gain this is very very inexpensive if the software is above anything I’ve ever come across before and don’t worry there are all kinds of levels so everyone will get to learn something now I will also leave a link link in the description for a free game you can play and get used to the software a little and you actually have to fix a car and there will be a high score and it would make me very very proud if you guys one of my viewers or subscribers would get that high score well if you’re going to play that game please put D be diagnosed then in front of your name so when you get the high score everybody will know that you wanna my viewers now I’m not gonna lie and it’s kind of hard to hide but I’m really excited about elected if you are a visual learner like I am this is the software to go through just look at the details and look at the visuals now the amount of in-depth knowledge you can gain from elected is second to none now there are hundreds of classes like this one on a three-phase AC electric motor used in hybrid and electric vehicles now the information a lecture provides you with is hard to come by it isn’t just general information but to give you an insight look and detailed information about how its component works like the insides of this DC to DC transformer now it isn’t just all reading they also make you do experiments to get a better understanding of the fundamentals now it isn’t all about hybrid and electric vehicles components of conventional vehicles like this ignition coil also get explained in great detail now if you weren’t excited yet you’re gonna be excited right now one of the greatest features about electrode is their simulator you get a customer complain and you need to diagnose and fix a real car now you got all tools available like a scanner or let’s do a measurement with a scope let’s start the car painted great I will leave a link in the description of this video so you can play that free elected simulator challenge when you log in the software will recognize where you’re logging in from and you can play the game in language make sure you beat the best diagnostician from all around the world and get that high score when you log in with my initials DD in front of your name so we all know when you get that high score at one of the subscribers of diagnosed then has fixed it again now let’s return to our Mazda confirm the customer complained and see if it’s actually misfiring [Music] customer complained confirmed we saw the check engine light coming on and off indicating we have got a misfire we could also see that the engine was running very very rough the next thing we’re gonna do is hook up a scan tool and check for any misfire codes now let’s see if the snap-on can auto ID this vehicle no problem this is the car we’re working on let’s go to engine and just like we expected we’ve got a misfire and a P O 303 is telling us that misfire is occurring on cylinder number three our scan so confirmed we have got a misfire it’s even telling us we’ve got a misfire on cylinder number three now to be a hundred percent sure we’re chasing the right cylinder let’s do a cylinder drop test to confirm that code [Music] [Applause] and of course our scan to was right we’ve got a debt misfire on cylinder number three now what do you think is the next thing we should test for an NGO to run it needs three fundamentals being spark compression and fuel now since we have a debt misfire on cylinder number three we’re missing one of those fundamentals so our next step should be to check what we are missing on that debt cylinder now the first thing I’m gonna check for is spark just because the coils in this engine are very accessible so it’s basically the easiest thing to start with now there are multiple ways to check for spark but in this video I’ll be using a very simple spark tester now as you could see that coral was firing just fine now can we rule out an ignition problem well not yet we could still have a faulty spark plug so just to be a hundred percent sure we don’t have an ignition problem I’m gonna swap out that number three coil and plug with the known good of number two a little tip in between and a note to myself when you’re tall like I am you’re changing plugs and coils and you’ve got a lift available you might just as well use it just to make you work a little bit more comfortable [Music] [Applause] [Laughter] [Music] now just to rule out an ignition problem we need to do that cylinder drop test again now let’s see if our problem moved from cylinder number three to seal num number two now since we ruled out an ignition problem the next thing we’re gonna check for is compression this is a great opportunity to check out this new tool this is a relative compression meter made by dot X dot X is a company that makes automotive test equipment now I’ve never used it before but I thought this video would be a great opportunity to test it together with you guys now let’s make sure the engine doesn’t start to run by unplugging the ignition coils now let’s start out by selecting compression when doing the voltage method and we’re doing it unsink since we already know we’ve got a problem on cylinder number three we’ve got four cylinders so let’s press Start I must tell you guys I’m impressed come on ten seconds to figure out if your engine is mechanically in good shape come on that’s fantastic unfortunately for the customer this engine isn’t in good shape as you can see we’re losing compression on two cylinders and one cylinder has got no compression at all now it looks like cylinder number two has got no compression but since I didn’t hook up the accessory to sync to the cylinder the bars are just in random order but this tool is definitely ending up in my diagnostic tool box I mean considering it doesn’t even cut more than a good compression meter that’s fantastic I’m leaving a link in the description of this video now just for fun let’s hook up an old-fashioned compression meter to a known good cylinder number one and let’s compare it to that bad cylinder number three [Music] [Music] now are we done diagnosing this car I guess some of you guys are screaming yeah we’re done but as a diagnosis I like to get answers answers to question like why is the cylinder losing compression now to answer that question we need to do a cylinder a leak down test mm-hmm a leak down tester usually has got two gauges one gauge will be the amount of pressure you’re putting into the cylinder the other gates worry the amount of leakage now when the cylinder is okay and is holding pressure it will read 0% now everything in the green is considered okay if it’s in yellow you’ve got a moderate leak everything in the red is considered a high league the gate runs all the way from zero to 100% in order to do a cylinder leak down test we need to get the piston in top dead center with the intake and exhaust valves closed then pressurize the cylinder and determine where the pressurized air is leaking from now although this is not necessary and I would normally not do it on this engine I’m gonna remove the valve cover just for educational reasons to show you guys exactly what we’re doing [Music] [Applause] [Music] I want to start out by doing a leak down test on our known good cylinder number one I got the piston in top dead center I got the exhaust and the intake cam facing upwards so they’re not pushing down on the valves so all the valves are closed right now and the cylinder should be sealed now as you can see there’s no leakage on cylinder number one everything in the green or beyond is considered fine in the yellow area you’ve got a moderate Lake and once you’re in the red area then you’re in serious trouble then you’ve got a high league now let’s do the same test on cylinder number three 80% that’s bad news on this customer is not going to be happy the last thing we need to do to conclude this diagnosis is to figure out where the air is escaping from if it’s blowing by the piston rings the air is escaping into the oil pan if we’ve got a leaking exhaust valve the air is leaking into the exhaust system and if we’ve got a leaking intake valve the air is leaking into the intake manifold now if the air is blowing by the piston rings it’s ending up in the oil pan so when I take the dipstick out I should be able to hear the air coming out of here absolutely nothing our piston rings are fine now if we’ve got a leaking intake valve that air is ending up in this intake manifold so when I open up this throttle valve we should be able to hear the air rushing out now I can hear absolutely nothing so it appears to be nothing wrong with their intake valves now I’ve got to mention one more thing there is a small possibility the air is not coming out of this exhaust right now there is another way foot it air to escape can you tell me how exactly the head gasket if we had a bad hat gasket the air could escape into another cylinder or into the cooling system now if the air was escaping into another cylinder we would have two dead cylinders because the air could go both ways now if the air was going into the cooling system this would cause cooling problems now I didn’t hear the customer complain about any cooling problems and that’s why I didn’t mention it in the first place now I can hear the air coming out of this exhaust but I doubt the camera is going to pick it up so to prove my point we’re gonna have a little fun [Music] now that’s how you diagnose a misfire caused by a leaking exhaust valve now if you want to learn more about the die text tool I used in this video there’s a link in the description box there’s also a link for the free diagnostic game on the elected website make sure you guys play it and get that high score over there and make me proud just make sure you put my initials DD in front of your name so I know you’re one of my subscribers now if you like this video and if you want to learn more please subscribe to my channel and when you hit the little bell you will get a notification each time I post a new video diagnosed then fix it again see you next time guys hi everyone welcome back to another Pine Hollow out of Diagnostics hmm interesting I’ve got my trusty headlamp and my trusty duct tape and we’re gonna fix this your car no pots needed hmm interesting [Music]


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