How to Fix a Car that Idles Poorly (Rough Idle)

hey guys chris fix here and today i'm going to show you how to fix your car if it's not idling properly and we're going to be doing 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 rpms 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 so 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 all right so clutch in we are in neutral and let's start up pay attention to those rpms and you can see the engine rpms are about 14 to 1500 rpms and that is way too high now normally when an engine starts sure it might go up to 500 rpms but after about a minute it drops down to around 800 rpms this never drops down even if the engine is fully warmed up you drive around for 10 minutes the rpms stay high like that and that makes me think that it's a dirty idle air control valve and it's stuck open allowing too much air in which keeps the idle high and even if i rev the engine up and let the idle drop down it still stays at 1500 rpms which is too high so that is why i think it is a dirty idle air control valve now the idle air control valve could also cause the engine to idle low let me show you that in the pickup truck so now i'm going to start the truck and watch the rpms and as you can see the idle is incredibly low if you press on the gas it revs no problem and feels nice and smooth but once you let go it drops down the engine shakes and it almost stalls so right away it's making me think we have a dirty idle air control valve that's stuck closed it's not allowing enough air to the engine which is keeping those rpms low now other symptoms you might encounter are if you put a load on the engine the rpms fluctuate they drop down they almost stall the engine for example if you turn the headlights on that puts a load with the alternator that could cause the rpms to drop or flutter if you put a load with the air conditioner compressor turn the ac on that could also cause the rpms to fluctuate and flutter 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 that your idle air control valve is dirty and it's worth giving it a clean to see if it alleviates those problems so now you have an idea of the symptoms of a dirty idle air control valve where is this located so you could remove it and clean it well it's actually usually pretty easy to find what you want to do is you want to find your air filter box this is where the air filter is that cleans the air coming in follow the intake tubing and go to your throttle body and right away you can see your idle air control valve right here 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 and without damaging your engine so that's where it's located right here sometimes it's located to the side sometimes it's located underneath or maybe it's a little bit back here on the intake manifold you just want to look in this general vicinity around the throttle body now let's check out the mustang real quick again you want to find the air box which is right here and then follow that intake tubing to the throttle body which is right there and right away you can see here is the iac valve now if your car is more modern like this 2014 maserati and uses an electronic throttle body so a throttle body that doesn't have a direct connection with a cable like this so there's a motor in here when you press on the gas it sends an electrical signal right to this motor and 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 you have this which could regulate your idle since it's electronic the computer could say hey open it up just a little bit and have the idle exactly where it needs to be so odds are electronic throttle body means you don't have an iac and then you'll have to look for something like a vacuum leak if your idle is fluctuating so 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 actually work on it that way you know why you're doing certain things such as cleaning it so i have an intake manifold here and here is the throttle body we have the idle air control valve right on top and let me show you how this works so the throttle body is what regulates the air going into the engine if you just give it a little bit of gas then it allows a little bit of air in and allows your car to accelerate if you floor it it opens that butterfly valve all the way now when you let off the gas and that closes completely how do you get air into the engine because you need air in here in order to keep the engine running well that's where the iac comes into play since the air can't get past that throttle plate what this does is it allows 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 so the computer tells this valve hey open the valve up we need more air or hey close the valve because we have too much air and that's how it regulates the rpm and here's an up close view so you have a better idea of how this works the air comes in right here and if the computer is saying hey close the valve it lowers the valve and plugs that hole if it says hey we need more air it opens the valve depending on how much air it needs and it'll let more air in so over time that valve could 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 on it which could really gum it up and make it stick all right so now that you know how this works let's go and clean it and it's very simple first let's get our safety glasses on so nothing gets in our eyes and all you're gonna need to clean this is some type of intake throttle body or carburetor cleaner anything like that that could dissolve carbon deposits either of these will work and if you do have some type of brush a toothbrush a pipe cleaner anything like that to get in there to get that carbon agitated will help very much you don't necessarily need to have a gasket it's super inexpensive this was like two bucks it's good to have when you reinstall it that way you know for sure you don't have any vacuum leaks and then finally you're gonna need some type of socket set very simple let's go and remove our idle air control valve so first we need to unplug the electrical connector from the valve then there's two bolts that need to be unscrewed so let's break the first one loose and unscrew it the rest of the way good then break the second one loose and unscrew that the rest of the way and now the idle air control valve can be removed the last thing to do is to tape off the opening that goes into the intake so no dirt or debris gets into your engine beautiful and 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 and this is a similar process unplug the electrical connector then remove the rubber intake tube and now we can remove the two bolts holding in the iac starting at the top good and to get to the bottom one i'm removing the pcv hose and now we can unscrew the bottom bolt with the bolt removed now the iac comes right out and the gasket fell off so let's get that as well and then finally tape off the hole so no dirt or debris gets into the engine all right so now that we have both of the idle air control valves removed let's go take a look at how dirty they are starting with the truck if you take a look in here you can see the carbon deposits which doesn't look that bad but you can definitely tell it's dirty also the valve looks like it's stuck closed yep would you look at that the valve was stuck in the closed position and that's definitely why the engine was idling so low now let's take a look at the idle air control valve on the mustang and it's a little bit different the air comes in through here and it exits through here and looking at this valve it also has some carbon deposits on it but it doesn't look horrible let's check the other side and here you can see there's some deposits on the valve shaft which could be causing it to stick open alright so you got to see how dirty each of these are you got to see how each car idles with them now let's clean them and see if we could fix the idle and the most important thing when cleaning this the number one rule is to always keep this motor facing upwards if we face it upside down and we spray in here liquid could go down the shaft into the motor damaging the motor if we face it upwards and you spray it no matter how much you spray liquids not going to get up into that motor and you won't damage it so remember to keep the motor facing up now so we don't make a mess i have a little catch can and i have a glass jar that way as we clean we could empty all this into here and see what dirt and debris we removed and i'm going to be using the most common cleaner that i think most of you guys might already have and if not it's easy to get this i'll link it in the description it's just throttle body cleaner you could also use carb cleaner anything like that will work and all you need to do is spray the inside of the valve and use the pressure from the spray to knock loose any of the carbon and force it out of the valve and you can see the liquid coming out of the bottom is black instead of clear which means we're cleaning the carbon out now to more thoroughly clean this grab a thin pipe cleaner and just clean as much as you can poke around in there on the top cleaning the surface of the valve also clean the bottom as well and finally give it one more spray to flush everything out and that's all there is to it now check out how dirty this liquid is it should be clear let's spill it out onto a clean towel and it just turns that towel black and you can see all the carbon we removed from the valve and just take a look at that before and after so now that we got the truck iac valve cleaned let's move on to the drift staying and for this valve we're not going to be using any type of brushes no pipe cleaners no toothbrush nothing because i want to show you that even just spraying it with the carb cleaner will free this up so just spray the inside of the valve to dissolve the carbon and use the pressure from the spray to knock the carbon loose let's flip it over and do the other side as well make sure you get in there deep and spray at different angles and again we aren't going to be using a brush just to prove that this will still work using only throttle body cleaner and that is it that's all there is to cleaning it out just a couple seconds later and look at that it's nice and dark so let's check this out and you can see it's not as dark as when we use the brush but there are still plenty of specks of carbon which shows we cleaned it out also check out the before and after picks that is way cleaner so now both of these are cleaned obviously the one that had the brush is a little bit cleaner but again they'll both work so now let's go test them out now just like everything else in this video installation is super easy the hardest part is deciding whether or not you want to reuse your gasket if your gasket comes off what i would do is i would take a look at it i would see hey does it look like it's cracked does it look like it's going to leak in this case this gasket looks perfect so just put it back in place where it was make sure you line everything up now you want to make sure the mating surface is clean and smooth and if there's any leftover gasket material or corrosion you could use 800 grit sandpaper to clean it up but this is good as is so let's align the idle air control valve and hand tighten it down all the way now use a ratchet to snug up the bolts a little at a time going back and forth evenly tighten it down against the gasket that way we don't get any air leaks and don't over tighten it because it's screwed into aluminum and that'll easily strip good finally let's connect the electrical connector so that you can hear it click perfect so with that installed now let's go start up the truck and see if she'll idle properly all right moment of truth so when you first start your car your idle is going to be above a thousand rpms that's fine it should drop down slowly after about a minute or so and then eventually drop down below a thousand rpms and after about two minutes our idle settled at about 800 rpms and there we go cleaning the idle air control valve fixed the idle in the truck she wasn't even idling above 500 rpms before this and now she's idling perfect now let's go and see if cleaning the idle air control valve in the drift stand worked so let's remove the tape and then we can install the gasket and i'm reusing the old one because it looks fine there's no cracks or damage so get it aligned and then let's get the iac aligned and then tighten down the top bolt by hand so it holds it in place next let's get the bottom bolt in and hand tighten that as well and just like before snug up both bolts a little at a time back and forth to compress the gasket evenly to prevent air leaks good let's finish up by connecting the pcv hose and then the intake hose and finally connect the electrical connector so that you hear it click like that beautiful and that is all there is to it let's go test her out so let's see what we got and she started right up which is good so with the cold start the rpms are about 1400 which is fine and then that should slowly drop down just like that perfect and after a minute or so that'll drop down below a thousand all right and then after about two minutes the idol dropped all the way down to eight to 900 rpms and she's idling butter smooth and with that we've fixed the idol in the drift sting she is idling perfectly so there you go whether you have a low idle issue or 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 it's worth giving it a shot even if you're not sure if this is the problem because it's that simple to do it could still be a vacuum leak somewhere an egr leak something like that but again this is so easy to do you might as well just see if it fixes it and in this case it fixed both vehicles and this is actually a pretty common problem on fords for whatever reason the idle air control valve gets dirty this is one of my first videos i've ever done on my youtube channel back in the day i'll be sure to link that video right in the side here and in the description so you can easily find it if you're a fan of my channel definitely go check it out because it'll show you the difference between the old videos and the new ones and how much work goes into the new ones and the editing and all that stuff i think you guys appreciate it but as always hopefully the video was helpful if it was remember to give it a thumbs up if you're not a subscriber consider hitting that subscribe button and all the tools and products i used in this video are linked in the description

Channel: ChrisFix

Views: 4,539,181

Keywords: ChrisFix, IAC valve, idle air control valve, car idles rough, car idles up and down, idles and stalls

Id: KhvqT3blzVs

Length: 13min 51sec (831 seconds)

Published: Thu Sep 03 2020