DIY with Pics: Cleaning the IACV-SC400
10-03-12, 03:42 PM
#1
DIY with Pics: Cleaning the IACV-SC400
Hey CL
Here is a very short and easy DIY on how to clean the IACV, or Idle Air Control Valve on a 1992 Lexus SC400, but can be done on most any Lexus.
THIS WILL ONLY WORK FOR 92-93 IACV'S. IF YOUR IACV PART NUMBER IS #22270-50010 THEN THIS DIY IS FOR YOU!
What you need: (What I used)
1.Philips Screwdriver
2.Throttle body cleaner (I used CRC)
3.Towels or rag
I did not do an extreme cleaning, I just clean the basic easy-to-remove parts.
So how I started out is getting the throttle body cleaner spray and spraying the heck out of the tip of the IACV. Gunk, carbon and other buildup dripped off. I rubbed it VERY gently with a rag than did it again. I did this about 4 or 5 times before it was "good enough". Don't forget to get under the spring. The rings of the spring will move out of the way to clean underneath.
Filthy IACV that looked like it hadn't been cleaned in a LONG time.
Here is the throttle body cleaner I used. It worked pretty good.
OK, now for the dis-assembly. In the second picture you will see that the IACV has 3 nuts and tiny bolts. You only need the Philips screwdriver for removing these 3 little guys, the IACV has a socket built in were the tiny nuts are, so you do not need a tiny wrench to hold the other side. Pretty convenient, I think. The IACV will separate into 2 parts now. There will be a little resistance pulling the bearing part out because there is a magnet, so still be very gentle with it.There is a metal plate, a small metal plate, at the bottom of the rubber part of the IACV, don't lose that. Don't tip the IACV upside down or it will fall out and you will lose it forever. Don't know what it is, some electric connection I think... see picture below.
OK, now the IACV will have that one bearing. If you twist it left, (lefty loosey), it will come out. Again be careful, and use cation when cleaning the different parts of the IACV. Careful not to lose parts, you have the IACV in 3 separate parts now.
This is the IACV put together without the tiny nuts and screws put on. DO NOT LOSE THEM!!
Picture below is finished product, without hardware attached of course.
Picture of the tiny nuts and screws next to my finger. (No, my finger isn't that big.) Man, those screws are tiny!
This is a very easy task. Took me about 5 minutes, with pictures. Mod's can edit in places were i missed some stuff, or were I might have said something wrong. (I don't think I did!!)
I don't know about you, but this is equivalent to me go carting doing this sort of stuff..goodluck
Here is a very short and easy DIY on how to clean the IACV, or Idle Air Control Valve on a 1992 Lexus SC400, but can be done on most any Lexus.
THIS WILL ONLY WORK FOR 92-93 IACV'S. IF YOUR IACV PART NUMBER IS #22270-50010 THEN THIS DIY IS FOR YOU!
What you need: (What I used)
1.Philips Screwdriver
2.Throttle body cleaner (I used CRC)
3.Towels or rag
I did not do an extreme cleaning, I just clean the basic easy-to-remove parts.
So how I started out is getting the throttle body cleaner spray and spraying the heck out of the tip of the IACV. Gunk, carbon and other buildup dripped off. I rubbed it VERY gently with a rag than did it again. I did this about 4 or 5 times before it was "good enough". Don't forget to get under the spring. The rings of the spring will move out of the way to clean underneath.
Filthy IACV that looked like it hadn't been cleaned in a LONG time.
Here is the throttle body cleaner I used. It worked pretty good.
OK, now for the dis-assembly. In the second picture you will see that the IACV has 3 nuts and tiny bolts. You only need the Philips screwdriver for removing these 3 little guys, the IACV has a socket built in were the tiny nuts are, so you do not need a tiny wrench to hold the other side. Pretty convenient, I think. The IACV will separate into 2 parts now. There will be a little resistance pulling the bearing part out because there is a magnet, so still be very gentle with it.There is a metal plate, a small metal plate, at the bottom of the rubber part of the IACV, don't lose that. Don't tip the IACV upside down or it will fall out and you will lose it forever. Don't know what it is, some electric connection I think... see picture below.
OK, now the IACV will have that one bearing. If you twist it left, (lefty loosey), it will come out. Again be careful, and use cation when cleaning the different parts of the IACV. Careful not to lose parts, you have the IACV in 3 separate parts now.
This is the IACV put together without the tiny nuts and screws put on. DO NOT LOSE THEM!!
Picture below is finished product, without hardware attached of course.
Picture of the tiny nuts and screws next to my finger. (No, my finger isn't that big.) Man, those screws are tiny!
This is a very easy task. Took me about 5 minutes, with pictures. Mod's can edit in places were i missed some stuff, or were I might have said something wrong. (I don't think I did!!)
I don't know about you, but this is equivalent to me go carting doing this sort of stuff..goodluck
Last edited by SC400slide; 03-01-14 at 07:36 PM.
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MGa (04-03-17)
10-03-12, 07:44 PM
#2
1JZ Single SC400
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This is a great detailed thread for the cleaning. There is another thread somewhere about actually replacing the bushings in there while its apart. Again great effort, and I will move this thread under the performance and maintenance section. BTW, what resulted you to clean this? Bad idle, died at idle, unless on the gas a little, symptoms please. Make this much more appealing. Thanks!!
10-04-12, 07:27 AM
#3
I cleaned this IACV because I bought it at a junkyard....it was filthy. Though symptoms of when you need to clean the IACV is when there is a bad idle, slow acceleration, rpm's moving around...TPS would make these symptoms too as well as bucking and kicking at any speed. It came out of a 1993 SC400 with no paint, no transmission, and most parts were gone besides the engine itself. Is this appealing enough? 
10-05-12, 10:21 AM
#4
Lead Lap
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SC400Slide. I pulled my IAC off (what a nightmare) and cleaned it per your DIY. Mine looked as bad as yours. Cleaned reinstalled and now things are worse. Before the cleaning I was having a rough idle and the car ran rough but I did not have cold start problems. Now after the cleaning I have cold start problems and my idle has dropped from 700-800 rpms to about 500 rpms. When I cleaned the IAC I made sure I put all parts back which was only the strange looking metal piece that sits in the bottom.
Any suggestions??
Any suggestions??
10-05-12, 12:32 PM
#5
A couple threads that might be your problem:
https://www.clublexus.com/forums/rx-...-too-high.html
https://www.clublexus.com/forums/gs-...t-shaking.html
Are you sure you plugged all of the vacuum lines in? and di you plug the plug wires in the correct cylinder, if you did take them out? I wonder if that metal plate has a "backwards"
https://www.clublexus.com/forums/rx-...-too-high.html
https://www.clublexus.com/forums/gs-...t-shaking.html
Are you sure you plugged all of the vacuum lines in? and di you plug the plug wires in the correct cylinder, if you did take them out? I wonder if that metal plate has a "backwards"
10-05-12, 01:18 PM
#6
Lead Lap
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Slide, thanks for your help and advice. I think the IACV might be going through the relearn process it seems to be getting better as I drive it. I'm talking about the idle. The other problem of feeling like it is not running on all 8 with no power is still there
10-05-12, 02:41 PM
#7
SC400Slide. I pulled my IAC off (what a nightmare) and cleaned it per your DIY. Mine looked as bad as yours. Cleaned reinstalled and now things are worse. Before the cleaning I was having a rough idle and the car ran rough but I did not have cold start problems. Now after the cleaning I have cold start problems and my idle has dropped from 700-800 rpms to about 500 rpms. When I cleaned the IAC I made sure I put all parts back which was only the strange looking metal piece that sits in the bottom.
Any suggestions??
Any suggestions??
Trending Topics
10-05-12, 05:11 PM
#9
Well, not to be rude, but the internet is there still... Resetting the ECU will make the car "reset" everything. It is sort of like the refresh button on the internet. Your car will re-learn it's factory settings this way, and resetting the ECU will also make the CEL leave. If it comes back you know you have a problem. It's simple to reset the ECU. Just disconnect the negative battery cable for 20 minutes or so, (just to be safe) than re-plug it in. Tell us if anything comes back for further reference on this site. GL!
10-05-12, 07:45 PM
#10
Lead Lap
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Thanks man. Don't worry about rude. Tough skin. Love to learn and don't mind searching. Use to own an 8 series BMW. You haven't seen crap until you deal with German engineering.
I've got a guy coming over about noon tomorrow to pull codes. Should I reset the car prior to him coming over?
I've got a guy coming over about noon tomorrow to pull codes. Should I reset the car prior to him coming over?
09-24-19, 08:24 AM
#14
Just wondering... I can't see the pictures clearly because there is Photobucket watermark on all of them! Is it something only I experience or others have the same issue? Appreciate some help on how to access the pictures.
so try to make these pics work! 
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