Idle air controller?
05-31-2010, 09:05 PM
#1
Idle air controller?
I posted up an issue for my daughter and have gotten some great responses but none of them seem to have fixed the issue. I did a call in to a local automotive talk show and the recommendation I got was to replace the idle air controller? Now I'm not too sure just what this is suppoed to be or where it is located. If anyone knows what this might be, please feel free to tell me! I really do appreciate it. this site really makes me look like a hero to my kids when I ahve to work on their trucks ... and mine!
Last edited by Ritzy4Runner; 06-03-2010 at 12:46 PM.
05-31-2010, 11:18 PM
#2
Registered User
Lol.....well, it is nice when someone can fix the vehicles. I'm my wife's hero. 
I'd have to assume what they mean is the idle air control valve. There can be different terms used according to what manual your looking at, what year/design, and who the heck made it.
Anyway, I don't what issue you posted, so it would help if I could get up to speed. Maybe post a link to the thread you refer to? Or, just tell me what's going on?
I'd have to assume what they mean is the idle air control valve. There can be different terms used according to what manual your looking at, what year/design, and who the heck made it.
Anyway, I don't what issue you posted, so it would help if I could get up to speed. Maybe post a link to the thread you refer to? Or, just tell me what's going on?
06-01-2010, 10:05 PM
#3
Lol.....well, it is nice when someone can fix the vehicles. I'm my wife's hero.
I'd have to assume what they mean is the idle air control valve. There can be different terms used according to what manual your looking at, what year/design, and who the heck made it.
Anyway, I don't what issue you posted, so it would help if I could get up to speed. Maybe post a link to the thread you refer to? Or, just tell me what's going on?
I'd have to assume what they mean is the idle air control valve. There can be different terms used according to what manual your looking at, what year/design, and who the heck made it.
Anyway, I don't what issue you posted, so it would help if I could get up to speed. Maybe post a link to the thread you refer to? Or, just tell me what's going on?
Thanks for any help or suggestions
06-01-2010, 10:20 PM
#4
Idle air controller, also called the Idle Air Control valve (Or IAC for short) is located on the bottom of the throttle body. It has a plug with 3 wires and two water lines plugged into it.
This is a bad picture, but this is what you will be looking for:
This is a bad picture, but this is what you will be looking for:
06-01-2010, 10:22 PM
#5
btw that is for the 5VZ. I have no idea what sort of vehicles your kids drive, and every Toyota model is different. Toyota uses the same general idea for most of their vehicles.
If your daughter drives a vehicle with a 3.0 in it, they cast the IAC into the throttle body so you have to replace the whole throttle body.
If your daughter drives a vehicle with a 3.0 in it, they cast the IAC into the throttle body so you have to replace the whole throttle body.
You've got to be kiddin me!
So the "fix" for my issue is that I am going to have to find a thottle body with a good IAC? I hate to ask but what is that gonna cost me? I will have to investigate this further. Thanks DC
06-02-2010, 09:08 AM
#7
Registered User
People have had luck with simply cleaning the valve. If that doesn't work, if the IAC is the issue or even part of it, unfortunately you do have replace the whole throttle body. It's a thermal wax design.
http://www.autoshop101.com/forms/h21.pdf
The FSM also covers testing the valve. Fortunately, this is easy.
Did you ever check the TPS?
http://www.autoshop101.com/forms/h21.pdf
The FSM also covers testing the valve. Fortunately, this is easy.
Did you ever check the TPS?
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06-02-2010, 11:15 AM
#8
Not yet, as she lives about an hour away so getting to work on it is tough. I'm hoping to get it for aobut a week so that I can check some of these things out. I hope the IAC can be cleaned easily, and if so I hope that will resolve the issue. Then it will be on to replacing the spark plugs Thanks for your inputs!
06-02-2010, 09:09 PM
#10
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Plug the hole inside the throttle body before the butterfly valves.Just take off the intake hose and put a piece of tape over the hole which should be located at about 4o'clock. If all runs well, permanently plug it. That hole runs the automatic choke(also known as the AAV (aux air valve) and you will now have no high idle but should let you know if that is the problem.
Hope that helps,Dave
Hope that helps,Dave
06-02-2010, 09:25 PM
#11
Not crazy about "plugging" up holes for things espcially when it was designed for the ability of high idle. thei issue here is to determine the cause, not to correct the symtom. So if I do plug up that hole what does that tell me? what really needs to be replaced so it will operate as original? thanks for the info and method of checking
06-02-2010, 11:03 PM
#12
Registered User
Here's the thing....
The IAC valve purpose is to allow supplementary air (supplementary to what's already being drawn through the idle bypass....the hole behind the idle adjustment screw.......the one with the big flat head on it in the throttle body) into the intake during cold start and the warm up period. At this point it is supposed to be open. So, it won't pose any idle problem until the motor warms up. Nor will it being open pose any problem while the truck is being driven until it warms up. When the motor has reached operating temp, though, the valve should be closed. But, if it's stuck open, it's allowing too much air throwing off the air/fuel ratio. It will idle poorly and potentially cause the motor to stall when coming to a stop. Likewise, if the IAC is stuck shut, then you will have problems when the motor's cold because the supplementary air it's supposed to supply is not there. If you follow this then you can see the logic in the testing in methods given by WestCoast or in the link provided or in the FSM. To further clarify, the type of IAC valve you have is a thermal wax design. When the motor (coolant) is cold, the wax should be contracted causing the valve to remain open. But, the when the motor/coolant has gotten hot, it causes the wax to expand and therefore the valve to close. But again, if the valve is sticking, it can't do either reliably.
So, you can't be sure it's a problem with the IACV until you test it. Does that help?
Don't permanently plug it, though. That's just not even necessary or wise.
The IAC valve purpose is to allow supplementary air (supplementary to what's already being drawn through the idle bypass....the hole behind the idle adjustment screw.......the one with the big flat head on it in the throttle body) into the intake during cold start and the warm up period. At this point it is supposed to be open. So, it won't pose any idle problem until the motor warms up. Nor will it being open pose any problem while the truck is being driven until it warms up. When the motor has reached operating temp, though, the valve should be closed. But, if it's stuck open, it's allowing too much air throwing off the air/fuel ratio. It will idle poorly and potentially cause the motor to stall when coming to a stop. Likewise, if the IAC is stuck shut, then you will have problems when the motor's cold because the supplementary air it's supposed to supply is not there. If you follow this then you can see the logic in the testing in methods given by WestCoast or in the link provided or in the FSM. To further clarify, the type of IAC valve you have is a thermal wax design. When the motor (coolant) is cold, the wax should be contracted causing the valve to remain open. But, the when the motor/coolant has gotten hot, it causes the wax to expand and therefore the valve to close. But again, if the valve is sticking, it can't do either reliably.
So, you can't be sure it's a problem with the IACV until you test it. Does that help?
Don't permanently plug it, though. That's just not even necessary or wise.
Last edited by thook; 06-02-2010 at 11:06 PM.
06-03-2010, 02:27 AM
#14
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this might be the problem with my truck when its cold sometimes the truck stalls on me when i try pull out...an when it warms up it doesnt stall and i tuned it up and have a brand new tps but still stalls when its cold sometimes
06-03-2010, 05:27 AM
#16
Here's the thing....
The IAC valve purpose is to allow supplementary air (supplementary to what's already being drawn through the idle bypass....the hole behind the idle adjustment screw.......the one with the big flat head on it in the throttle body) into the intake during cold start and the warm up period. At this point it is supposed to be open. So, it won't pose any idle problem until the motor warms up. Nor will it being open pose any problem while the truck is being driven until it warms up. When the motor has reached operating temp, though, the valve should be closed. But, if it's stuck open, it's allowing too much air throwing off the air/fuel ratio. It will idle poorly and potentially cause the motor to stall when coming to a stop. Likewise, if the IAC is stuck shut, then you will have problems when the motor's cold because the supplementary air it's supposed to supply is not there. If you follow this then you can see the logic in the testing in methods given by WestCoast or in the link provided or in the FSM. To further clarify, the type of IAC valve you have is a thermal wax design. When the motor (coolant) is cold, the wax should be contracted causing the valve to remain open. But, the when the motor/coolant has gotten hot, it causes the wax to expand and therefore the valve to close. But again, if the valve is sticking, it can't do either reliably.
So, you can't be sure it's a problem with the IACV until you test it. Does that help?
Don't permanently plug it, though. That's just not even necessary or wise.
The IAC valve purpose is to allow supplementary air (supplementary to what's already being drawn through the idle bypass....the hole behind the idle adjustment screw.......the one with the big flat head on it in the throttle body) into the intake during cold start and the warm up period. At this point it is supposed to be open. So, it won't pose any idle problem until the motor warms up. Nor will it being open pose any problem while the truck is being driven until it warms up. When the motor has reached operating temp, though, the valve should be closed. But, if it's stuck open, it's allowing too much air throwing off the air/fuel ratio. It will idle poorly and potentially cause the motor to stall when coming to a stop. Likewise, if the IAC is stuck shut, then you will have problems when the motor's cold because the supplementary air it's supposed to supply is not there. If you follow this then you can see the logic in the testing in methods given by WestCoast or in the link provided or in the FSM. To further clarify, the type of IAC valve you have is a thermal wax design. When the motor (coolant) is cold, the wax should be contracted causing the valve to remain open. But, the when the motor/coolant has gotten hot, it causes the wax to expand and therefore the valve to close. But again, if the valve is sticking, it can't do either reliably.
So, you can't be sure it's a problem with the IACV until you test it. Does that help?
Don't permanently plug it, though. That's just not even necessary or wise.
People have had luck with simply cleaning the valve. If that doesn't work, if the IAC is the issue or even part of it, unfortunately you do have replace the whole throttle body. It's a thermal wax design.
http://www.autoshop101.com/forms/h21.pdf
The FSM also covers testing the valve. Fortunately, this is easy.
http://www.autoshop101.com/forms/h21.pdf
The FSM also covers testing the valve. Fortunately, this is easy.
06-03-2010, 07:11 AM
#17
Registered User
Okay. Well, you can test the original once it's off the vehicle. Just stick it in the fridge or heat it up with propane torch or heat gun. Then test to see if the inlet is open or closed.....blah, blah.
So, can I have the original one if it's still good?
So, can I have the original one if it's still good?
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