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Step By Step Cleaning Instructions For IACV(idle Air Control Valve)/isc/throttle


Description

Step by step instructions on cleaning the IACV/throttle body

Hello Everyone,

I know IACV has been a huge topic on the forum and I have found various pictures in the RX forum and ES forum on the idle air control valve (IACV) or as others call it the idle speed control valve (ISC). However, I have not found a "step by step" posting to date which definitively shows how to clean this thing so that my car stops giving me idling problems.

Symptoms I have had included:

- low and rough idling that would cause the car engine to start shaking after starting the car

- this eventually got worse to the point that when I start my car, it would not idle unless I gave it gas

- idling problems for me tended to occur more often after my engine was warm or had been sitting in the sun

I hope these series of postings help you fellow LOC members out there. You've certainly helped me in the past so here's my two cents at this common problem. Additionally, the instructions I give are the way in which I have cleaned it myself. As you go about and attempt this, you may find better ways to do so. Please add and refine my instructions/terminology as needed. I am not a professional. I've only changed my oil, air filters, and conducted minor maintenance previously. The bottom line is that if you have the right tools, you should be able to do this. This discovery/ cleaning took me about 2 hours to do cause I ran into problems and there were major steps left out in previous postings that I've encountered read. The next time I do this, I believe I can get this done in about an hour or less.

Tools Needed:

1) Tightly fitting Philips Screw Driver

2) Carb cleaner that is O2 sensor safe (I've seen CRC. I used Valvoline Carb Cleaner)

3) Locking Grip Pliers (definitely helped me remove the factory tight screws)

4) Small brush for cleaning

5) Towels for cleaning

6) Pliers (help removed brackets holding the hoses)

7) Latex gloves helps with limit the messiness.

* I used the same gasket and did not replace it. No problems found.

1) Remove the hose that comes from the engine/motor that connects to the air intake hoses.( Hose is below in red – we'll refer to this as Hose A) When you pull back the rubber hose covering, you will see that a metal bracket is holding the hose pretty tightly in place. Use the pliers to clasps the two metal pieces together to loosen the bracket and pull the hose loose. You can also do this by hand if it's easier for you.

original_2.JPG

2) Upon removing the hose, you will want to remove the two air intake hoses. Loosen the three screws above in green and remove the hose. Below is a picture of the intake hoses removed.

intake_hoses_only.JPG

3)After removing the intake hoses, I opened the lid to the air filter and moved this to the side of the car to create more working room. I believe there are two clips on the right holding the lid in place. Just pop the two clips and move the cover to the side. I also took out the air filter and temporarily moved this to the side.

intake_hoses_removed.JPG

4)After removing the intake hose, the throttle body/IACV/black electric coil is revealed. At this point, I removed the black electric wire from the black coil. Once the electric wire is removed you can remove the black coil from the IACV by removing the two screws. Note, the screws are factory tight so use a tight fitting screw driver to remove the screws. One of my screws was partially stripped from the dealership's work, so I had to resort to my locking grip pliers which helped out tremendously. After removing the two screws, the black electric piece pops right off. When the black electrical coil is removed from the IACV, it exposes a small pencil sized metal stud. You will also notice a washer that sits on this stud. Don't lose this washer. Take it and put it aside so it doesn't fall off when you continue on in the next steps.

throttle_body_revealed2.JPG

5)Additionally, I removed the hose coming out of the IACV. We'll call this Hose B. This hose can be removed in the same manner by clamping the bracket and pulling the hose out. You will see that the hose is removed below. Below are pictures of before and after.

sensor_removed2.JPG

6)Here is where the fun begins. I initially attempted to remove the four screws attached to the IACV at this point, but found that after an hour, this would be nearly impossible to remove considering the location of the screws were in an extremely tight spot. The only way I would be able to remove the IACV is to remove right throttle body. Not as tough as it sounds. Three screws need to be removed to accomplish this. Again, be careful when removing the screws. Also you will see I removed another electric plug and I also cut a tie wrap. Once you complete these steps, the throttle body/ IACV comes out pretty easily. Note when you remove the throttle body, there will be one LAST hose connected to the IACV. Be careful when you remove this hose as radiator fluid may spill. Some of my fluid spilled out so I just refilled my coolant after I was done.

throttle_body_connected2.JPG

7)Below is a picture of the bottom view of the IACV. You now can EASILY remove the four screws connecting the IACV to the throttle body . In the picture below, I have already removed one of the screws.

bottom_view_iacv.JPG

Once the four screws are removed the IACV and throttle body separate. Now you can clean both of them with your carb cleaner, brush, towels, cotton swabs etc…. Picture here is before I the cleaning with all the muck inside

iacv_removed.JPG

Pictures after I cleaned the IACV and throttle body

This last picture is the post throttle body cleaning

iacv_post_cleaning.JPG

iacv_upclose.JPGpost_throttle_body_cleaning.JPG

8) Once you are done cleaning, just put back the throttle body/iacv the same way you took it off, and put everything back in reverse order. Ensure the gasket is in place. Also, ensure you put the washer back on the electric coil. Make sure you place hose A & B back and ensure the electric plugs are back in their original position. Once these things are in place, then it's all about putting the air filter/hoses back and you are good to go. If you have lost any coolant, make sure you refill it to a safe level.

After completing this cleaning, my car starts up without any problem and idles as if I just purchased the car brand new. Replacing this at a dealership would have costed me $300-400 easily. Let me know if you have any questions. Cheers (Also, I tried to post these as separate replys, but the software combined all my replies into a single reply and did not keep them separated)

*Edited the posting to have the pictures follow step by step in sequential order*



Recommended Comments

Thanks for the detail explanation.

But please, I need to confirm if this is what i need to get down in my own case.

I use a 2001 RX 300. I have to crank it more than once before it starts. It runs smoothly though and no other observed issued but the multiple cranking for it to start. The only recent thing I did before this cranking problem started was a change of my Oxygen sensors and Air flow sensor because of an issue of black exhaust smoke and bad gas mileage. These issues have resolved and the present issue is just the multiple cranking to get it started.

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