Car Engine Cutting Out Only Drives Slow How to Check Air Intake System

That's full power. My foot's on the floor. Go.

Hey, friends, it's Len here from 1A Auto. In this video, we're going to talk about car breathability issues. Essentially, every time your car is running, it's going to need to be able to breathe in through the intake and breathe out through the exhaust. In this particular video, we're going to talk about the breathing in aspect of it. So, let's get started. Now, firstly, what I want to talk about is inside your internal combustion engine, you should have approximately 14 parts of air for every 1 part of fuel getting burnt inside the engine. Now, of course, if this mixture was a little bit off, your engine's more than likely still going to run, but you might notice some runnability issues. Now, if you have a ratio imbalance, that's typically going to come down to the fact that either you have too much fuel or too much air getting into your combustion chamber. So, if you were to come over to pretty much any car, you're going to find that it has an air filter, and it needs to have an air filter because, of course, any air that it's breathing in to get burnt up needs to be clean and free of any debris. If for some reason you had an air filter inside of here that was clogged up or restricted in any way, that's going to cause another issue.

So, now the air filter housing is typically going to have some sort of inlet that leads into it. And generally, it's going to be either in the front or along one of the sides of the engine compartment. If you happen to see that there's any obstruction on your air inlet tube, that's obviously going to cause an issue where you're not getting enough air into your engine. Now, just because your air inlet is free and clear of debris, it doesn't mean that we shouldn't check the air filter housing. Let's go ahead and open this up. Let's grab onto that air filter. Really? What's this? Obviously, keeping your snacks inside your air filter box isn't probably the best idea. But let's talk about the air filter. Now, a lot of times air filters when you pull them out are going to look great. This one actually looks pretty good overall in exception of the fact that it's pretty much kind of peened over and bent. Any of these fins that are bent over like this could potentially cause air restrictions, which, of course, is going to starve the engine of air. A lot of times, if you were to go ahead and open this up, you might find that there's a whole bunch of debris inside here. Commonly, you're going to find leaves, dirt, even maybe some acorn debris, or something like that inside there typically from a mouse of some sort. If air can't make its way through the air filter, it's not going to be able to make its way to the engine.

Now, some of the symptoms that you might happen to find if you were having an issue with restricted air flow into the engine might be your engine just tries to start and it's not very easy, essentially like a hard start. So, maybe you crank, crank, crank, it sounds like it wants to run, but essentially it's just kinda like [vocalization]. And it just doesn't want to crank over and it definitely doesn't want to stay running. That would be an extreme condition. Other than that, you might happen to notice that you have a check engine light on. That's something that obviously you're going to want to pull the codes to. And more than likely, it's going to come up with a mass air flow sensor code and probably a couple others that you're going to want to pay attention to. Now, if the engine does happen to start, you might happen to hear weird noises or odd sounds coming from the engine compartment, maybe even pop the hood and you can hear a whistling sound, a chattering noise, or even a [vocalization] essentially just from something being lodged inside there, restricting the air flow. You might also notice that you're having a rough idle. Essentially if you're just sitting still at a red light or in a parking lot with the engine running, you can kind of feel the engine kind of shutter a little bit, and it feels a little shaky. And in a little bit more of an extreme case, you might notice an engine misfire, which essentially is kind of be...kind of like that shutter, but typically, you're going to feel a misfire under acceleration or under load.

With that said, something else that you're probably going to notice is reduced horsepower or essentially acceleration off the line. Now, on an older car like this, you're going to notice different symptoms than on a newer car. A car like this doesn't have a mass air flow sensor. So, there's no way for the car's computer to know exactly how much air is getting drawn into the engine. Essentially with this, if you had a clogged air filter, the engine is just going to keep trying to suck more fuel in to be able to keep running. And essentially, what you're going to notice is poor acceleration, less power, and more than likely, a whole bunch of black smoke coming out that tailpipe. So, now, essentially, if you happen to find that there's a restriction inside your air inlet systems, such as maybe something like this blocking where the air inlet is, or even if you were to look inside of the housing here and you happen to find that there's debris or a little snack, make sure you get any of that out of there, and make sure that the air filter is not restricted in any way. If you happen to look at the air filter itself and you find that it's damaged in any way, like with this one where it's kind of peened over and you can tell that the air might be restricted or even baffled as it's trying to get through, that could potentially be an issue.

Essentially, if you were to look inside here, and like I said before, if you see a whole bunch of debris or anything like that, it really only makes sense to go ahead and replace the air filter. Some people might try to blow it out with a little bit of compressed air. But the only thing about that is that there is a lot of fibers in this air filter that's supposed to collect debris. If you spray it with compressed air, especially directly onto it, you could potentially spread those fibers, which essentially means you're going to be having debris making its way past the air filter and into the engine. So, now, let's just do a quick experiment outside. So, let's take a look at what's going on with this with a scanner real quick. Essentially, on the left, we have the RPMs or the engine speed revolutions per minute, and then over on the right, we have the mass air flow sensor. So, essentially, this is going to be graphing the amount of air getting drawn into the engine. We're doing this prior to having any restriction on the air filter. So I'm just going to go ahead and start up the car. You can see our RPMs came right up. That looks great. At this point, everything's going to start leveling out. So, as you can tell the mass air flow sensor leveled out and it's doing exactly what it's supposed to.

Now, let's test it with a restriction. So, we can see that the RPMs jumped right up. And right now, with the air restricted, you can tell that it's kind of fluctuating a little bit here. Let's go ahead and give this a little bit of acceleration. I'm accelerating. I'm all the way down on the floor right now. My check engine light came on and it died. And after the restriction, here are some of the codes that you might happen to see. Now, if you have a restriction inside your air system which causes a check engine light, essentially what might potentially happen is your automobile might go into limp mode. What limp mode's supposed to do is make it so you can get off to the side of the road safely without the engine completely turning off. Essentially, it's going to kind of cut back a lot of that power and just give you enough so you can get off the side of the road without causing permanent damage to your engine. Okay. So, now that we cleared our restriction, you might want to find another place to try to hide your snacks.

Aside from that, I hope you liked the video. Maybe you learned a little something along the way or maybe you have a story of your own, either way, leave it in the comment section below because I always love to hear from you. If you liked the video, smash on the like button for me, it would mean the world. While you're at it, go ahead and subscribe and ring the bell. That way there, you can be kept up with all of our latest content. Thanks.