Idle air control valve ?

g_rizzo · 04-05-2011, 01:34 AM

Can someone expalin the symptoms of a bad idle air control valve, i know the bearings are not ceased in it but whats the best way to tell if it is bad, also the hose going into it the large 1/2inc from the intake are they always slightly kinked going into the vale

90 Turbo A.T

Bru · 04-05-2011, 05:09 AM

There is a test procedure in most repair manuals. It's a "stepping motor" so that means to get the valve plunger to move in one direction you have to activate the positive pins in a sequence. The reverse sequence moves the plunger in the opposite direction. After shutting off the engine you should hear a buzzing clicking sound that is indicative of a functioning idle control valve. You can disassemble and check for crud build up on the plunger and clean it. Be sure to get the check valve that goes into the intake manifold installed in the correct direction. The rubber diaphragm goes into the manifold body. Under turbo boost conditions it blocks air from backing out through the idle valve. If your hose is pinched it may not be a factory formed hose. It should have the same texture as the other hoses used on the intake bellows.

Midwest_Mudder · 04-05-2011, 05:18 AM

I may be having issues with mine, haven't had the time to test it yet. Idle is all over, yet timing is perfect, new plugs new wires and no vacuum leaks. It'll go up, stick, then come down too far and nearly kill it, if i tap the gas it sticks then will drop too far, then over correct. It does this when warm and when cold. Motor runs strong in all other aspects. Back when I had a neon (the only other computer controlled car I have owned) it's IAC went bad and was doing the exact same things. I was told I could have possibly saved it by cleaning it up.

So, my question is, what is the best way to clean the dang thing. There was some gunk in my throttle body when I bought the car so its not a far reach to think the ICV would be gunked up also. I don't want to pull it off, then clean it with something and have whatever I used kill it.

Also, if it does need replaced, what all other toyota cars have the same part in them? I've found out pretty fast that you put "Supra" in front of the part the damn auto places tack on an extra 50 bucks.

Anyway, not meaning to threadjack, I believe this is all on topic, and I didn't want to make another post when it could all be answered here.

Bru · 04-05-2011, 06:16 AM

Make sure the throttle position sensor is in adjustment and working. You'll need an ohm meter, a set feeler gauges, an S shaped phillips screwdriver for tight places and the repair manual procedure to do that. It's helpful to have a couple alligator clip wires.

g_rizzo · 04-09-2011, 08:11 PM

I have cleaned the valve and fixed the hose going into it. Now the car will stall from time to time without warning. I think i will check the TPS

04-05-2011, 01:34 AM	#1
g_rizzo Stock Join Date: Mar 2011 Location: Canada Posts: 6	Idle air control valve ? Can someone expalin the symptoms of a bad idle air control valve, i know the bearings are not ceased in it but whats the best way to tell if it is bad, also the hose going into it the large 1/2inc from the intake are they always slightly kinked going into the vale 90 Turbo A.T

04-05-2011, 05:09 AM	#2
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	There is a test procedure in most repair manuals. It's a "stepping motor" so that means to get the valve plunger to move in one direction you have to activate the positive pins in a sequence. The reverse sequence moves the plunger in the opposite direction. After shutting off the engine you should hear a buzzing clicking sound that is indicative of a functioning idle control valve. You can disassemble and check for crud build up on the plunger and clean it. Be sure to get the check valve that goes into the intake manifold installed in the correct direction. The rubber diaphragm goes into the manifold body. Under turbo boost conditions it blocks air from backing out through the idle valve. If your hose is pinched it may not be a factory formed hose. It should have the same texture as the other hoses used on the intake bellows. Last edited by Bru; 04-05-2011 at 05:17 AM.

04-05-2011, 06:16 AM	#4
Bru Bone Stock w Upgrades ;-) Join Date: Apr 2010 Location: Tampa Bay Posts: 210	Make sure the throttle position sensor is in adjustment and working. You'll need an ohm meter, a set feeler gauges, an S shaped phillips screwdriver for tight places and the repair manual procedure to do that. It's helpful to have a couple alligator clip wires. Last edited by Bru; 05-19-2011 at 01:45 AM.

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04-05-2011, 05:18 AM	#3
Midwest_Mudder Stock Join Date: Apr 2011 Location: Kennard, NE Posts: 2	I may be having issues with mine, haven't had the time to test it yet. Idle is all over, yet timing is perfect, new plugs new wires and no vacuum leaks. It'll go up, stick, then come down too far and nearly kill it, if i tap the gas it sticks then will drop too far, then over correct. It does this when warm and when cold. Motor runs strong in all other aspects. Back when I had a neon (the only other computer controlled car I have owned) it's IAC went bad and was doing the exact same things. I was told I could have possibly saved it by cleaning it up. So, my question is, what is the best way to clean the dang thing. There was some gunk in my throttle body when I bought the car so its not a far reach to think the ICV would be gunked up also. I don't want to pull it off, then clean it with something and have whatever I used kill it. Also, if it does need replaced, what all other toyota cars have the same part in them? I've found out pretty fast that you put "Supra" in front of the part the damn auto places tack on an extra 50 bucks. Anyway, not meaning to threadjack, I believe this is all on topic, and I didn't want to make another post when it could all be answered here.

04-09-2011, 08:11 PM	#5
g_rizzo Stock Join Date: Mar 2011 Location: Canada Posts: 6	I have cleaned the valve and fixed the hose going into it. Now the car will stall from time to time without warning. I think i will check the TPS