IAC valve
I bought a car that has a bad idle air control valve. I want to know if it is save to drive it home, I will only be driving 5mins to get home. So in those 5 mins will the car be save enough to make it home.
My car has 164000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hello. Your car should be safe enough to drive home. The one risk of this may be that it could potentially leave you stranded momentarily, but most of the time even when this valve is not working properly, it will still allow the car to run, albeit not run very well. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine. This valve is controlled by the vehicle’s computer which will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage.
When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed. This is all done by the idle air control valve. When the engine RPM drops below the normal range of 750-800 RPM (for most cars), this may indicate a dirty or faulty idle air control valve. If you need further help with an idle air control valve replacement, a certified technician from YourMechanic can assist with this repair.
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A bad IAC can potentially lead to stalling, which can compromise vehicle safety. Plus, you won`t pass a state emissions test if the check engine light is on due to a bad IAC. As such, you should replace a faulty IAC as soon as possible.
It works by allowing air to bypass a closed throttle plate when the engine is at idle and, for this reason, is also referred to as the air bypass valve. In a fuel-injected engine, a throttle body regulates how much air enters the engine.
What happens if idle air control valve is stuck open? If your car`s idle air control valve is stuck open, it will cause the engine to idle at a higher than normal rpm. This can lead to decreased fuel economy and increased wear and tear on the engine. In some cases, it can also cause the engine to stall.
Yes. The fuel injectors are designed to work under a certain amount of fuel pressure.
The most common sensor which can lead to your car stalling is the manifold absolute pressure sensor (MAP) or the mass air flow sensor (MAF). Most cars typically have one or the other.
Set the multimeter to measure Ohms, place the red lead on one terminal of the idle air control valve solenoid, and place the black lead on the other terminal. If the IAC valve is in good condition, you get a resistance between 7 and 25 Ohms, depending on its model. Another value means the unit is bad.
The idle air control valve is programmed to regulate and maintain the engine idle speed at a constant rate. If the valve fails or has any issues it can cause the idle speed to be thrown off. This may result in an unusually high or low idle speed, or in some cases a surging idle speed that repeatedly climbs and falls.
The higher your Reset RPM is above your idle RPM, the higher you`ll need the Reset Position. Another trick is to play with the min and max duty values so that the IAC can`t close enough to allow the engine to stall. I generally aim to have the engine idling warm with no more than 5% on the IAC position.
The duty cycle frequency of an idle air control valve solenoid is about 100 Hz, other motor management systems can have different frequencies. The duty cycle signal at idle is usually 40-45% for the opening solenoid and the opposite for the closing solenoid, so 60-55%.
If your powertrain control computer is misreading idle speeds, this can cause a high idling malfunction. When your car`s throttle is malfunctioning, this can cause your car to stall or idle high. Often this is a result of dirt buildup in the air intake. Other times it can be a problem with a cracked intake tube.
There are three major causes for a stalled engine: A lack of fuel, a lack of air flow and improper ignition. Running out of fuel is one of the most common causes of engine stalling, but dirty fuel injectors or a plugged fuel filter can also be the culprit. Your engine needs air to run properly as well.
If your powertrain control computer is misreading idle speeds, this can cause a high idling malfunction. When your car`s throttle is malfunctioning, this can cause your car to stall or idle high. Often this is a result of dirt buildup in the air intake. Other times it can be a problem with a cracked intake tube.
The IAC valve should not effect trans shift from 2nd to 3rd gear. If you experience stalling from a cold start or low idle speed or stalling when the headlights, air conditioning and or steering is cranked fully to one side, address the IAC problem first.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
New IAC Valve – High Idling but old IAC Valve normal (800/900 rpms) 1993 Saab
ANSWER : Hello – I think you were on the right track with the idle air control valve. It sounds like your engine is getting extra air from an intake leak somewhere. It’s also possible there is a throttle body problem. The "multiple tries to start" problem sound like the fuel pump check valve bleeding down overnight. The fuel pump has to work extra long on first startup each day to compensate for no residual fuel rail pressure. Putting a fuel gauge on the fuel rail will confirm/reject this possibility. For diagnostic assistance, I recommend a high idle inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
Read Full Q/A … : IAC valve
Car had a hunting idle so replaced Iac valve and now it idles at 2200 rpm’s cold and 1000 rpm’s warmed up.
ANSWER : Hello. You car does have an adaptive memory when it comes to the idle control valve. Over time the computer is going to adjust the placement of the valve to compensate for water and carbon build up. In some cases, driving the vehicle around 100 miles straight will cause changes. But more importantly, going through 20 or more key cycles will cause the idle control valve to adapt.
The best way to resolve this would be to use a factory scan tool that will allow you to go into the computer and clear this adaptive memory back to factory. If you are looking to have this done, consider using YourMechanic, as a certified mechanic can come to your home or office to inspect and repair your high engine idle speed problem.
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Does a 2.7l engine iac valve fit a 2.4l iac valve
ANSWER : Hello and thanks for writing in. The IAC valve for the 2.4L and 2.7L motors should be interchangeable for years 2000-2004.
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Air suspension valve not working pump works but no air comes out of valve to struts
ANSWER : If air is getting to the valve but not coming out, odds are yes the valve is bad. Unfortunately there is no rebuilding kit for them. It most likely will have to be replaced then the entire system will need to be checked for any other leaks or faults.
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I have to replace my IAC valve myself but don’t know how to go about it.
ANSWER : Hi there. You will need the basic hand tools to remove engine accessories to access the IAC (Idle Air Control) Valve. The valve is located on the throttle body and is held on with either Allen head screws or Torx head screws. There is a plug that you will have to remove before you take off the valve. To remove the part, you need to remove the throttle body from the engine. There are Allen head screws or Torx head screws that hold the throttle body on the engine along with the hose clamp to the intake hose. Be sure to clean the throttle body with throttle body cleaner when it is off. If you need further assistance with your IAC replacement, then seek out a professional, such as one from Your Mechanic, to help you.
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Will a sticking valve burn out my variable valve timing solenoid?
ANSWER : Hi there. Typically a sticking valve does not cause the VVT solenoid to fail, but it can increase vacuum pressure inside the motor that will lead to other timing related issues, which can trigger the same error codes.
Anytime you have a cylinder head hardware issue, or any other mechanical problems, it’s important to have a professional mechanic, such as one from YourMechanic, determine exactly why the Check Engine Light is on before additional damage occurs.
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Missing IAC valve vacuum line.
ANSWER : The IAC (Idle Air Control) valve is required to have a vacuum line on it to work the engine properly. The line from the carbon box filter is supposed to be hooked to it, but it may be damaged. Take the hose on the carbon box filter and suck on it to see if it holds a vacuum. If it does, then I suggest hooking up the hose to the IAC. If it does not, then I recommend replacing the carbon box filter and then hooking up the vacuum hose to the IAC. If you need further assistance with your vacuum lines disconnected, then seek out a professional, such as one from Your Mechanic, to help you.
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Please help me figure out where my PCV valve and PCV Hose is!!!
ANSWER : Hi there. The PCV valve is located on bank 1; the valve cover closest to the cabin. It is usually found under the intake plenum towards the passenger side of the vehicle. The hose will be attached; or loose. Please understand that a code retrieval and an internet search is not a proper diagnosis as there are several other possibilities that can cause the code to set. Some of the possible causes could be spark plugs, ignition coils, intake manifold leaks, intake plenum leaks, vacuum hose leaks, failing airflow meter, failing O2 sensors, exhaust manifold leaks, low fuel pressure, failing ECU, faulty wiring harness, failing injectors, etc… As you can see, the list of possibilities runs on and on. This is where the expertise and experience of a qualified technician with the proper diagnostic tools and procedures becomes invaluable. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts and determine the exact cause of the code. Your Mechanic has several available technicians that can assist you with a check engine light inspection.
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