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Hey guys, Chris Fix here. Today I'm going to show you how to fix your car if it's not idling properly, and we're going to do that by cleaning the idle air control valve. This valve regulates the air going into the engine at idle. It maintains your idle, which should be around 800 RPM or so. The problem is this valve gets clogged up by carbon deposits, which could keep the valve stuck open or stuck closed, therefore messing up your idle. In this video I'm going to show you how to clean this at home very easily. All of you guys will be able to do it after you're done watching the video, and I have two perfect examples of how to do this.
First, we have the Drift Sting, which has a high idle. Let me show you. Clutch in, we are in neutral, and let's start up. Pay attention to those RPMs. You can see the engine RPMs are about 1400 to 1500 RPM, and that is way too high. Normally when an engine starts, sure, it might go up to 1500 RPM, but after about a minute it drops down to around 800 RPM. This never drops down, even if the engine is fully warmed up. You drive around for 10 minutes and the RPMs stay high like that, and that makes me think it's a dirty idle air control valve stuck open, allowing too much air in, which keeps the idle high. Even if I rev the engine up and let the idle drop down, it still stays at 1500 RPM, which is too high. That is why I think it is a dirty idle air control valve.
The idle air control valve could also cause the engine to idle low. Let me show you that in the pickup truck. I'm going to start the truck and watch the RPMs. As you can see, the idle is incredibly low. If you press on the gas, it revs with no problem and feels nice and smooth, but once you let go it drops down, the engine shakes, and it almost stalls. Right away it's making me think we have a dirty idle air control valve that's stuck closed, not allowing enough air to the engine, which is keeping those RPMs low.
Other symptoms you might encounter: if you put a load on the engine, the RPMs fluctuate, drop down, or almost stall the engine. For example, if you turn the headlights on, that puts a load on the alternator, which could cause the RPMs to drop or flutter. If you put a load on with the air conditioner compressor by turning the AC on, that could also cause the RPMs to fluctuate, flutter, or maybe even stall the engine. Turning the steering wheel, if you have power steering, could cause the RPMs to fluctuate. Putting the car in reverse, maybe you throw it in reverse and it stalls, or you put it in drive and it stalls. If you have any of those symptoms, there's a good chance your idle air control valve is dirty, and it's worth giving it a clean to see if it alleviates those problems.
Now you have an idea of the symptoms of a dirty idle air control valve. Where is it located, so you could remove it and clean it? It's usually pretty easy to find. What you want to do is find your air filter box, which is where the air filter is that cleans the air coming in. Follow the intake tubing to your throttle body, and right away you can see your idle air control valve. This is also known as an IAC valve or an air bypass valve, whatever you want to call it. Don't worry, I'm going to show you how to clean it properly without damaging the valve or your engine. Sometimes it's located to the side, sometimes underneath, or maybe a little bit back on the intake manifold. Just look in this general vicinity around the throttle body.
Let's check out the Mustang real quick. Find the air box, which is right here, then follow the intake tubing to the throttle body, which is right there, and right away you can see the IAC valve.
If your car is more modern, like this 2014 Maserati, and uses an electronic throttle body, meaning a throttle body that doesn't have a direct cable connection, there's a motor in it. When you press on the gas, it sends an electrical signal right to this motor, which opens and closes the throttle body. If you have an electronic throttle body like this, odds are you do not have an IAC valve because you don't need one. Since it's electronic, the computer can say, open it up just a little bit and have the idle exactly where it needs to be. So odds are an electronic throttle body means you don't have an IAC, and you'll have to look for something like a vacuum leak if your idle is fluctuating.
Now that you know where to find the IAC valve, let me show you how it works, because I think it's very important to understand how something works before you work on it. That way you know why you're doing certain things, such as cleaning it. I have an intake manifold here, and here is the throttle body. We have the idle air control valve right on top. The throttle body is what regulates the air going into the engine. If you give it a little bit of gas, it allows a little bit of air in and lets your car accelerate. If you floor it, it opens that butterfly valve all the way. Now when you let off the gas and it closes completely, how do you get air into the engine? You need air in here to keep the engine running well. That's where the IAC comes into play. Since the air can't get past the throttle plate, what this does is allow air up in front of the throttle plate to go through this hole and back down into this hole, which goes into the intake, and it feeds the engine enough air to keep it idling at the proper RPM. The computer tells this valve, open up, we need more air, or close, we have too much air, and that's how it regulates the RPM.
Here's an up-close view so you have a better idea of how this works. The air comes in right here. If the computer says close the valve, it lowers the valve and plugs that hole. If it says we need more air, it opens the valve depending on how much air it needs and lets more in. Over time, that valve can get clogged up. For example, check out this IAC with 300,000 miles on it. You can see the valve has carbon on it, which could prevent it from closing all the way. Also, the valve stem over here has carbon deposits, which could really gum it up and make it stick.
Now that you know how this works, let's clean it. It's very simple. First, let's get our safety glasses on so nothing gets in our eyes. All you'll need to clean this is some type of intake throttle body or carburetor cleaner, anything that could dissolve carbon deposits. Either of these will work. If you have a brush, a toothbrush, a pipe cleaner, anything like that to get in there and agitate the carbon, it will help very much. You don't necessarily need a gasket. It's super inexpensive, about two bucks, and it's good to have when you reinstall, so you know for sure you don't have any vacuum leaks. Finally, you'll need a socket set. Very simple.
Let's remove the idle air control valve. First, unplug the electrical connector from the valve. Then there are two bolts that need to be unscrewed. Break the first one loose and unscrew it the rest of the way, then break the second one loose and unscrew that the rest of the way. Now the idle air control valve can be removed. The last thing to do is tape off the opening that goes into the intake so no dirt or debris gets into your engine. It really is that simple to remove the idle air control valve, and it's even easier to clean it.
Now let's remove the IAC from the Mustang. It's a similar process. Unplug the electrical connector, then remove the rubber intake tube. Now we can remove the two bolts holding in the IAC, starting at the top. To get to the bottom one, I'm removing the PCV hose, and then we can unscrew the bottom bolt. With the bolts removed, the IAC comes right out, and the gasket fell off, so let's get that as well. Finally, tape off the hole so no dirt or debris gets into the engine.
Now that we have both idle air control valves removed, let's see how dirty they are, starting with the truck. Inside, you can see carbon deposits, which doesn't look that bad, but you can definitely tell it's dirty. The valve also looks like it's stuck closed. Yep, the valve was stuck in the closed position, and that's definitely why the engine was idling so low.
Now let's look at the IAC valve on the Mustang. It's a little different. The air comes in through here and exits through here. This valve also has some carbon deposits, but it doesn't look horrible. Let's check the other side. You can see some deposits on the valve shaft, which could be causing it to stick open.
So you've seen how dirty each of these are, and how each car idles with them. Now let's clean them and see if we can fix the idle. The most important rule when cleaning this is to always keep the motor facing upwards. If we face it upside down and spray in here, liquid could go down the shaft into the motor and damage it. If we face it upwards and spray, no matter how much you spray, liquid won't get up into that motor, and you won't damage it. So remember to keep the motor facing up. To avoid making a mess, I have a little catch can and a glass jar, so as we clean we can empty everything into here and see what dirt and debris we removed.
I'm going to use the most common cleaner, which most of you might already have. If not, it's easy to get; I'll link it in the description. It's throttle body cleaner. You could also use carb cleaner. Anything like that will work. All you need to do is spray the inside of the valve and use the pressure from the spray to knock loose any carbon and force it out of the valve. You can see the liquid coming out of the bottom is black instead of clear, which means we're cleaning the carbon out.
To more thoroughly clean this, grab a thin pipe cleaner and clean as much as you can, poking around in there. On top, clean the surface of the valve. Also clean the bottom. Finally, give it one more spray to flush everything out, and that's all there is to it. Check out how dirty this liquid is. It should be clear. Let's spill it onto a clean towel, and it turns that towel black, showing all the carbon we removed from the valve. Just look at that before and after.
Now that we've cleaned the truck's IAC valve, let's move on to the Drift Sting. For this valve we're not going to use any brushes, no pipe cleaners, no toothbrush, nothing, because I want to show you that even just spraying it with carb cleaner will free it up. Spray the inside of the valve to dissolve the carbon, and use the pressure from the spray to knock the carbon loose. Flip it over and do the other side as well. Make sure you get in there deep and spray at different angles. Again, we're not using a brush, just to prove that this will still work using only throttle body cleaner. That's all there is to cleaning it out. Just a couple of seconds later, and look at that, it's nice and dark. You can see it's not as dark as when we used the brush, but there are still plenty of specks of carbon, which shows we cleaned it out. Check out the before and after pictures too. That is way cleaner. Both of these are cleaned. The one that had the brush is a little cleaner, but both will work.
Now let's test them out. Just like everything else in this video, installation is super easy. The hardest part is deciding whether or not to reuse your gasket. If your gasket comes off, take a look at it. Does it look cracked? Does it look like it's going to leak? In this case the gasket looks perfect, so put it back in place and make sure everything lines up. Make sure the mating surface is clean and smooth. If there's any leftover gasket material or corrosion, you can use 800 grit sandpaper to clean it up, but this is good as is. Align the idle air control valve and hand tighten it all the way. Then use a ratchet to snug up the bolts a little at a time, going back and forth evenly, tightening against the gasket so we don't get any air leaks. Don't overtighten, because it's screwed into aluminum and that will easily strip. Finally, connect the electrical connector until you hear it click.
With that installed, let's start up the truck and see if she'll idle properly. Moment of truth. When you first start your car, your idle will be above a thousand RPM. That's fine. It should drop down slowly after about a minute and eventually drop below a thousand RPM. After about two minutes, our idle settled at about 800 RPM. There we go: cleaning the idle air control valve fixed the idle in the truck. She wasn't even idling above 500 RPM before this, and now she's idling perfectly.
Now let's see if cleaning the idle air control valve in the Drift Sting worked. Remove the tape, then install the gasket. I'm reusing the old one because it looks fine, with no cracks or damage. Get it aligned, then get the IAC aligned, and tighten the top bolt by hand so it holds in place. Next, get the bottom bolt in and hand tighten it as well. Just like before, snug up both bolts a little at a time, back and forth, to compress the gasket evenly and prevent air leaks. Finish by connecting the PCV hose, then the intake hose, and finally the electrical connector until you hear it click. That's all there is to it. Let's test her out.
She started right up, which is good. On the cold start, the RPMs are about 1400, which is fine, and that should slowly drop down. After a minute or so it drops below a thousand. After about two minutes, the idle dropped all the way down to 800 to 900 RPM, and she's idling butter smooth. With that, we've fixed the idle in the Drift Sting. She is idling perfectly.
Whether you have a low idle issue, a high idle issue, or your idle is bouncing around, that's how you clean your idle air control valve. It's quick, it's easy, and it's worth giving it a shot even if you're not sure it's the problem. It could still be a vacuum leak somewhere, an EGR leak, or something like that. But this is so easy to do, you might as well see if it fixes it. In this case it fixed both vehicles. This is actually a pretty common problem on Fords, for whatever reason, where the idle air control valve gets dirty. This is one of my first videos on my YouTube channel. Back in the day, I'll link that video in the side here and in the description, so you can easily find it. If you're a fan of my channel, definitely check it out, because it shows the difference between the old videos and the new ones, and how much work goes into the new ones, the editing, and all that. I think you guys appreciate it. As always, hopefully the video was helpful. If it was, give it a thumbs up. If you're not a subscriber, consider hitting that subscribe button. All the tools and products I used in this video are linked in the description.