Ilde Control Valve

[fnorman]

Gentlemen,

Car was hard to start and had a rough idle. The problem was carbon/dirt had fouled the ICV (Idle Control Valve). This valve's function is to provide path for air to bypass the butterfly assembly in the throttle body at idle; with out it functioning correctly the engine is starved for air. This is a common problem that can be remedied with a good cleaning process with carburetor cleaner.

When white electrical coil is removed from the ICV, it exposes a small pencil sized metal stud. This stud needs to rotate 1/8 turn feely and then one more additional 1/8 turn with some spring resistance for a total of a 1/4 turn. If this stud does not rotation freely, then the ICV will need to be cleaned.

08/092005

- No new gaskets were needed, used old ones with no problems.

- Caution, when removing the ICV from the throttle body. Great care must be taken not to strip out the four screw heads when breaking the factory torque. A very tight fitting screw drive is essential.

- DO NOT disassemble the ICV assembly after removing it from the throttle body; it has critical settings that may not be able to be maintained if reassembled.

More pictures...

http://www.thefilehut.com/userfiles/fnorman/DSC08219a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08220a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08221a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08222a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08223a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08226a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08227a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08228a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08229a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08230a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08233a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08234a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08236a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08237a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08238a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08239a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08240a.jpg

fnorman

[SKperformance]

Very nice for a first post.

Try and be more detailed in your explanation of things as you will get lots more questions,Like what to clean it with.

Why did you remove the cover,

how long and the usual.

It is such a common question on this forum because no one bothers to look.

[fnorman]

One more picture.

Global space settings will not let me post additional picturs. Sorry.

[fnorman]

corrections, see first post.

[mburnickas]

Gentlemen,

See pictures of Idle Control Valve.

Common problems with these cars is the idle control valve at the intake . It gets filled with carbon over time and makes it hard to restart your car when it is already hot. To remedy this clean the intake and iacv with throttle body cleaner. After the car will run amazing ,if not repeat until it is fixed.

fnorman

←

I like the pix. They are worth thousands to me! Keep posting!!!! Thanks :)

[Toysrme]

Small pictures suck. Here's the same pictures from CL, re-hosted.

IAC instructions Here

EGR instructions Here

[camlex]

Very Good info.

Thanks,

[eman_be_lexin]

Question, How did you get to this point? I opened the hood to my 97 to see what you are talking about and couldn't find it anywhere. I see the rubber tube connecting the air filter box to a the injector (I am not very automobile literate) but do not see what you have in the pic. Can you provice step by step instructions for this procedure starting from the beginning for those who haven't done this before?

[Toysrme]

The rubber air hose that runs to the throttlebody. The underside of the throttlebody is where it sits.

[eman_be_lexin]

Is it a simple process for the average person to perform or should I leave it to the professionals?

[Toysrme]

Very easy.

[justin97]

Very easy.

←

i could not get the second screw out well the one closesst to the radiator. i almost stripped it.

[fnorman]

corrections, see first post.

[Toysrme]

Good edit, nice new pics!

Surround your picture links with the img tags so they show up as pictures.

(img) www.picture.com (/img)

Replace () with brackets [ ]

Best to add a space, or two between pictures, they tend to run together without breaking up.

[hammer008]

thanks...very helpfull

[MNJack]

I am trying to gather info to do this job (clean IAC valve). I have had the stalling at initial startup problem, although only very rarely. Here is my current question:

I have the Haynes repair manual which recommends cleaning the throttle body with carb cleaner (make sure carb cleaner is safe with O2 sensor systems and cat converters) but they caution: Do not clean the throttle position sensor (TPS) or Idle Air Control (IAC) valve with the solvent.

So, what's up with this warning and what should I use to clean the IAC valve?

I also have the official Lexus repair manual, which states: NOTICE: To prevent deterioration, do not clean the throttle position sensor and IAC valve.

[Toysrme]

Which should read:

NOTICE

Allowing customers to clean their Throttle Plate, EGR, and Idle valve will result in the loss of both 2-4 hours labor charge over several visists, and parts charges for Idle Valve, EGR valve, EGR Modulator, Vacuum Hoses, Throttle Position Sensor, Intake Cleaning Service, and $1 can of STP cleaner for Fuel Injection Cleaning.

Clean it with a carb / tb cleaner & a small brush.

I have found Tri-Flow makes a good spray lubricant for post-cleaning.

The 1/2 an oz of solvent used in cleaning is not going to hurt an o2 sensor.

[leftiesrule]

Could somebody please give me some advice!! I cannot get those 4 screws loose. When you did it what method did you use to loosen them? I'd prefer not to take the throttle body off.

Also I took off one of the hoses connected to the iscv and some radiator fluid spilled out. Should I have drained the fluid before doing this? After trying to put that hose back on, it won't sit tight and still slides around with the clamp on.

This is my first time attempting to fix my car so please give me some pointers. I have a 2000 ES300.

[GoldenStateSilverSport]

Could somebody please give me some advice!! I cannot get those 4 screws loose. When you did it what method did you use to loosen them? I'd prefer not to take the throttle body off.

Also I took off one of the hoses connected to the iscv and some radiator fluid spilled out. Should I have drained the fluid before doing this? After trying to put that hose back on, it won't sit tight and still slides around with the clamp on.

This is my first time attempting to fix my car so please give me some pointers. I have a 2000 ES300.

Those four screws are sitting in a VERY VERY tight spot! The head of the screw is facing downward which makes it even harder to get access to. Additionally the two screws holding the IACV in place require much force to loosen and it is very very easy to strip the screws...be very careful

[azmalu]

Hey guys I am going to go through this process of cleaning ICV and throttle body but I remember even after doing this on my 94 maxima I had before that the shaking did not go away and while at a stop light etc as long as I put it into neutral it was okay. Does this sound more like a motor mount issue? The response to this thread seems like that might be the problem ... http://us.lexusownersclub.com/forums/index...4115&hl=icv

[OneGuyInCA]

Gentlemen,

Car was hard to start and had a rough idle. The problem was carbon/dirt had fouled the ICV (Idle Control Valve). This valve's function is to provide path for air to bypass the butterfly assembly in the throttle body at idle; with out it functioning correctly the engine is starved for air. This is a common problem that can be remedied with a good cleaning process with carburetor cleaner.

When white electrical coil is removed from the ICV, it exposes a small pencil sized metal stud. This stud needs to rotate 1/8 turn feely and then one more additional 1/8 turn with some spring resistance for a total of a 1/4 turn. If this stud does not rotation freely, then the ICV will need to be cleaned.

08/092005

- No new gaskets were needed, used old ones with no problems.

- Caution, when removing the ICV from the throttle body. Great care must be taken not to strip out the four screw heads when breaking the factory torque. A very tight fitting screw drive is essential.

- DO NOT disassemble the ICV assembly after removing it from the throttle body; it has critical settings that may not be able to be maintained if reassembled.

More pictures...

http://www.thefilehut.com/userfiles/fnorman/DSC08219a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08220a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08221a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08222a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08223a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08226a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08227a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08228a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08229a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08230a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08233a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08234a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08236a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08237a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08238a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08239a.jpg

http://www.thefilehut.com/userfiles/fnorman/DSC08240a.jpg

fnorman

Links to the pics are broke!

[camlex]

Looking for these pictures.

Thanks,

[homemechanic]

If you guys stripped the screw on the IACV, you can get them out with a pair of vise-grip. I stripped two of them and had to go with the vise-grip. I bought replacement screws at home depot. they are 5mm metric threads. just can't understand why toyota - lexus has to install screws that are a$$ tight. no point having all these extra torque when 4 screws are holding down such a small area.

[homemechanic]

If you guys stripped the screw on the IACV, you can get them out with a pair of vise-grip. I stripped two of them and had to go with the vise-grip. I bought replacement screws at home depot. they are 5mm metric threads. just can't understand why toyota - lexus has to install screws that are a$$ tight. no point having all these extra torque when 4 screws are holding down such a small area.

[punt]

I would thank all the posters and confirm that cleaning the idle air control valve worked for me.

I have a 99 ES300 with 140K miles. I have had all major service done at the dealer and stalling on starting still happened to me. I do confess that I use mid grade gas. I am not sure if this has anything to do with the fouling of the IAC but mine definitely was fouled.

I took off the air intake to the throttle body and took off the solenoid to the IAC. I removed the air assist line to the IAC to see the cleaner come out and also I did not want the cleaner in the engine. The valve stem was VERY difficult to turn. I sprayed GUMOUT throttle body cleaner ($4.50) into the air bypass in the throttle body and into the stem as much as possible while turning. After a minute of two the valve stem turned easily.

Make sure you do not lose the metal ring and the rubber o-ring when removing the IAC solenoid. Also make sure you put them back exactly as they came out. I must have put it back together wrong or lose because the first time I drove it after I put it back together it was revving up and down. I took it back apart and made sure it was together correctly and it works great. If it comes back again I will replace the IAC.

Thanks again to all that have posted! It save me a lot of money. The so called mechanic at a new shop I took it to wanted to replace the whole throttle body!!! Can you believe that? He said a new one with labor might be as much as $1000. I solved it with the help of you all for $4!