If your idle air control valve gets clogged with carbon buildup, your car will have a very poor idle. This has happened to me before. I will tell you right away, you don’t have to be a mechanic to clean your air control valve. I will guide you through the steps on how to clean your idle air control valve without removing it. Let’s talk more about the idle air control valve and what it does.
The idle air control valve has a mission to allow air to bypass your throttle plate at idle. When you press on the gas pedal, you open up the throttle plate and allow air from your air filter box to enter the engine. But at idle, with the throttle plate closed, there is a bypass which is going to allow air to go from the front side of the throttle plate when the throttle plate is closed and travel to the backside of the throttle plate and come out and enter your engine.
The job of your idle air control valve is to open up a valve that will allow air to only go through the bypass at idle. If this valve fails completely, you’ll have a really hard time starting your car or idling would be really rough. If the valve doesn’t fail but the passage gets clogged up with carbon buildup, then you also have very poor idle. In fact, you’ll like more likely to have a very low idling car.
How To Clean Idle Air Control Valve Without Removing It
Before I show you how to clean your idle air control valve without removing it, here is what you need to know. Always protect your hands and eyes while working on your car. Since you are going to be working with chemicals and possibly hot surfaces, use gloves, and eye protection.
1. Prepare the working area
Before I show you how to clean your idle air control valve without removing it, you have to prepare your working area. It may sound not important, but please only work when the engine is cold. It has happened so many times to me. I have a lot of scars on my hands from working on a hot engine. Also, if you have a pair of gloves, and safety glasses, please put them on.
2. Locate the idle air control valve
If you haven’t cleaned an idle air control valve before, you might have a hard time locating it. Start from the filter box and work your way up. The filter box is a large box that holds the air filter. Once you locate the air filter box, follow the duct past the mass airflow sensor (MAF) as it goes deep into the engine. You will then reach the throttle body and the idle air control valve. Depending on your car’s make and model, the idle air control valve is almost always attached to the throttle body.
3. Remove the filter box and the air duct
In order to disconnect the filter box, you will have to disconnect the clamps that are holding the filter box. Next, if your vehicle has a MAF sensor, disconnect the wiring that goes into the MAF sensor. Then, you want to remove all vacuum lines that are connected to this air duct. Make sure to remove the PCV hose that is connected to the big air duct.
4. Disconnect the clamps that connect the air duct to the throttle body
Undo the clamp that’s holding in the air hose to the throttle body by unscrewing the screws and disconnecting the clamps. Then, pull out the air hose and store it safely with all of the screws that you have just removed. At this point, you should have an exposed air filter and an exposed throttle body. When you get to this point, there is something that can also cause a rough idle and that is a dirty air filter. If you have a dirty or partially clogged air filter, that’s going to restrict the amount of air that’s getting inside your engine. This is going to be more noticeable at idle.
5. Locate the passage to the idle air control valve
With your throttle body exposed, you will be able to see a small ”hole” or passage that is located on the inside of the throttle body. This ”hole” or passage allows the air to bypass from the air duct into the engine when your car is idle. Inspect the hole and see if it has visible carbon build-up or something that may restrict the airflow.
6. Spray the hole with throttle body cleaner
Get yourself some throttle body cleaner. It doesn’t have to be fancy. The one that I am using is listed on amazon.com (see the price of throttle body cleaner here). Then with a plastic wire brush, clean the passage or passages even more. I got this cool plastic wire brush on amazon.com. The reason why I went for a plastic wire brush instead of a standard wire brush is that I don’t want to damage the passages or the throttle body.
7. Reconnect all of the components
After we clean everything up it’s time to put everything back together. The reconnecting part is going to be a reversal of removal. Just make sure that you don’t skip any steps. Reconnect one side of the air hose to the throttle body and secure it with screws and clamps. Then re-attach the airbox and re-attach the PCV hose and the vacuum hoses that you previously removed.
Word of caution
If you have a car that has an electronically operated throttle body plate, please make sure that you do not move the throttle body plate while cleaning the idle air control valve. The reason for this is if you touch the plate and move it around with your hand, you’re going to throw off the calibration. In order to reset that, you’re going to have to go to a dealer or a mechanic shop and that’s going to cost you money.