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DIY IACV clean picture write-up

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Old 07-03-10, 06:47 PM   #46
weinkaufjr
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141k miles on a 99 Rx 300. Had my first check engine light with an intermittent rough idle, a friend pulled a PO171 code for me. Reviewed this thread and http://www.clublexus.com/forums/rx-f...ne-light.htmls. I cleaned the MAF (it had looked pretty dirty) and throttle body especially were I understand idle air is redirected but I did not remove IAVC. Also put in new air filter. I had changed the plugs a few thousand miles ago prior to current problem. Disconnected the bat while I did this. Had to crank a little longer than normal but when it fired it up the code was gone and has stayed gone for several cycles. Starts great now and rough idle is gone.
Great search feature on the forum and helpful threads. Thanks for the tips.
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Old 08-15-10, 04:13 PM   #47
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Default What to do when things go wrong...

First, it's been about oh, 7 or 8 years since I posted on CL, some of you old timers might remember me

My 2001 RX300 AWD has about 117K miles on it now and I've been having problems starting it in the morning when it's cool out (less than 72 deg F). No CEL indicator. So after reading the forums here I decided to attempt the IACV cleaning.

Those 2 screws which hold the valve motor to the throttle body are a nightmare. The best way to get them off is with a #2 Phillips 1/4" drive bit. Take the bit, insert it into the screw head and give it a good rap with a heavy wrench or small hammer. This will help loosen the screw and cause the bit to bite into the head. I then use a ratchet with a 1/4" socket on the bit to loosen the screw. You have to apply constant pressure on the screw to keep the bit from slipping and stripping the screw head. I can not streess this enough. I was able to get one screw out sucessfuly, but on the second one I lost my concentration for a second and the screw head stripped instantly. These screw heads are soft and worthless.

I then spent the next 15 - 30 minutes painstakingly getting the screw out slowly with a needle-nose vise grips. My back hurts from being hunched over so long. The screw was runied, and today is a Sunday so no chance of getting one from the Toyo/Lexus parts dept. You do NOT want to replace these with the same philips head screws, you are simply asking for more trouble. Decided was going to try to find hex bolt head replacements.

The problem is that the remaining good screw would not thread properly into any of the bolt hole guides I have due to something unusual Toyota does to the screw tips. It came close to threading into a M5-.80 thread, so I took a chance that this would work since the original screw tip was slightly flared.

You want to buy 2 M5-.80 thread by 20mm bolts, two lock washers, and two flat washers. Lock washers against the screw head, flats next. Spray some WD-40 on the bolt threads before starting to thread into the throttle body mounting point. Using a 1/4" drive ratchet, they will be be snug/tight all the way you drive them, but no different than what the original screws feel like when tightening them. Using this solution I was able to secure the valve controller without fear of stripping a screw head. Doing a subsequent IACV cleaning will now be a piece of cake in the future.

Hope this helps someone else out,
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Old 08-15-10, 08:56 PM   #48
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Another way is to use torx screws....
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Old 08-29-10, 05:39 AM   #49
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I just did this and found that a normal size vise grips worked excellent. Grabs the outside of the screw and one twist and you hear it crack free and then go to a screw driver. I had tried needle nose vise grips and it slipped so went to regular size.

Unfortunately I ran into problems after that. I pulled the plastic part off and the rubber hose off and sprayed TB cleaner in, but my valve was completely frozen. I was trying to twist it when the wide part came off the shaft (later found out it is a magnet). I did get the valve moving and put the magnet back on and it seemed to hold and I put it back together, but now my car idles at 2500 to 3000 rpms (in park), 1250 rpms in drive so it drives along by itself at about 30 mph...

I ordered a new valve from amazon for $120.07 shipped which is nice but now I gotta wait and although I can drive it, I don't like the way it shifts and I have another car I can use.

Looks like I will have to drain the coolant and pull the throttle body off (per the manual) since those four screws holding the metal part of the IACV on are very hard to get to so good time to do the spark plugs and coolant flush and maybe new hoses...

BTW, I could not find the PCV valve anywhere t check it. I have a 2002 and heard it was redesigned, maybe it was eliminated? I guess on earlier years it is on the right side (passenger side) from another post (although they said left in their post I could see it was right side - drivers side is left, passenger side is right).

Last edited by mrbeefy65; 08-29-10 at 05:46 AM..
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Old 08-29-10, 06:29 AM   #50
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The PCV valve is still there in the same place, except it is now a metal insert with screws in. It's located on the rear left/passenger side. It's on the rear valve cover, on the left side (passenger side).
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Old 08-29-10, 11:21 AM   #51
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Quote:
Originally Posted by mrbeefy65 View Post
I just did this and found that a normal size vise grips worked excellent. Grabs the outside of the screw and one twist and you hear it crack free and then go to a screw driver. I had tried needle nose vise grips and it slipped so went to regular size.

Unfortunately I ran into problems after that. I pulled the plastic part off and the rubber hose off and sprayed TB cleaner in, but my valve was completely frozen. I was trying to twist it when the wide part came off the shaft (later found out it is a magnet). I did get the valve moving and put the magnet back on and it seemed to hold and I put it back together, but now my car idles at 2500 to 3000 rpms (in park), 1250 rpms in drive so it drives along by itself at about 30 mph...

I ordered a new valve from amazon for $120.07 shipped which is nice but now I gotta wait and although I can drive it, I don't like the way it shifts and I have another car I can use.

Looks like I will have to drain the coolant and pull the throttle body off (per the manual) since those four screws holding the metal part of the IACV on are very hard to get to so good time to do the spark plugs and coolant flush and maybe new hoses...

BTW, I could not find the PCV valve anywhere t check it. I have a 2002 and heard it was redesigned, maybe it was eliminated? I guess on earlier years it is on the right side (passenger side) from another post (although they said left in their post I could see it was right side - drivers side is left, passenger side is right).



Yep yours is metal. Just did mine, it's easy. http://www.clublexus.com/forums/rx-f...ml#post5533896
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Old 08-29-10, 01:45 PM   #52
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Yeah I had found it already, was looking for the plastic one that goes into a grommet in the valve cover. I am sure it's a better design with the metal one, but not as easy to change out...

Anyone else had the high idle with a bad IACV? I rechecked all connections and everything looked good, actually better than before I started. Last mechanic (or helper more likely) who worked on it left hoses barely connected or spring clips cutting the hose and there was one plastic clip holding the plastic shroud in front of the radiator on where there should be 6 or 7...

I actually tried bypassing the IACV by capping the line that supplies air to and it didn't make a difference. I am wondering if it is leaking around the plastic body now. Of course once the metal piece came off I figured I was done...
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Old 09-01-10, 02:48 PM   #53
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The new IACV fixed the problem with the high idle (2500 to 3000 rpm). I am not sure exactly what was going on with the old one...
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Old 11-06-10, 08:14 PM   #54
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Hello everyone,

I just did this DIY today. Here was my experience with the two brass screws: I used a middle or big size Philip screwdriver (as big as it can fits there), slowly turned until these 2 screws became loose. As long as you did it slowly but firmly, it is a piece of cake.

Quote:
Originally Posted by salimshah View Post
For folks who have not done this, the RX would not just fire-up like normal. It may take longer start time and a bit rough right after the process. Once things burn off, it should be fine.

Another tip from an other forum is ... tap the screw with the phillips screw driver/head in them. This helps break the bond in the threads and seats the screw driver head better. Just dont use the sledge hammer.

Salim
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Old 11-07-10, 07:05 AM   #55
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I usually find myself cleaning the IACV every few months, usually after a high idle. My screws have gotten to the point that they are no longer tight so I do not need to have a habit of trying to 'break' them loose.
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Old 11-20-10, 03:27 PM   #56
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Might put some antiseize on the threads next time
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Old 11-28-10, 02:13 PM   #57
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Quote:
Originally Posted by LALexusOwn View Post
Thanks for all the help Lexmex. Just to update my issue. I got the new IACV from www.rockauto.com and took some pictues of the old and new one side by side. You'll notice the old one on the left is filled with carbon in the right side air flow valve. The old IACV little magnetic drum would rotate in full 360 degree plus. The new one only would rotate the 1/4 or less turn just enough to open and close the valve. So, I guess the 360 plus rotations were the cause of my issues.

Further below is a picture of the new IACV with the black electronic cover taken off with the black inner washer seated into the casing and you can see the inner bronze wavy washer just behind the black washer.

for $160 for the part, I don't think it is so bad. My idle is now a perfect 1200 rpm cold in park and 750 rpm cold in drive and hot. It beats paying $600 for parts and labor at the dealership.
I'm thinking I might have to take a leap of faith and replace my IACV in order to rule it out as detailed in my other meesage thread regarding cold starts. Did RockAuto include a gasket with the new part? It looks like on their site it's an aftermarket AIRTEX.
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Old 03-02-11, 12:08 PM   #58
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Thank you tcheung!! Previously, the most I ever done to my car is change the oil...

My 2000 RX300 would die out immediately after starting. Luckily I was stuck in my own garage. Since I was unable to drive the car to the shop, I figured I'd try your directions. I went to the store to buy the cleaner, vice grip plier and a snub phillips. I followed your directions to the T, and now my rx is running smooth.

I had small trouble with one of the screws on the iacv, but eventually got it loose with the pliers without damaging anything (phew!). I gave it a tap like SALIMSHA suggested, and that did the trick.

When I first encountered the IACV lever, it did not feel impeded to me, and I had thought at that point that I did all that work for nothing. But after I sprayed the cleaner as directed, I noticed that the lever became extremely loose and free-spinning (back and forth). That gave me hope. It took me a while to get everything back in place (no wonder they charge so much). When I fired her up, my rx sputtered for a couple of seconds (which I expected from reading this thread), and then purred at about 1100 rpm. After I drove around the block the rpm sat nicely around 750-800 (I don't know if this is optimal or not, it just feels right to me).

Next day: Check Engine light and VSC lights came on. Not sure if I damaged a sensor while doing this procedure. Off to another thread...

Thanks again! My wallet thanks you.

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Old 11-02-11, 12:46 PM   #59
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Default es300 stalled on cold start when shifting into gear. Problem solved

First off,Thanks tcheung87, ArcherIII, Lexmex, Code58, LALexusOwn, and Nuckingfut, for the great tips.

I used this DIY on my 1999 ES300 1mz-fe w/VVti. It matches up exactly.

The rpms on my ES would drop dramatically when I shifted into gear on a cold start. Sometimes it would even stall. After doing this DIY and cleaning the throttle body intake valves the problem appears to have gone away.

I used vice-grips to remove the screws after trying just the Phillips screwdriver. And I removed the lower hose to let the fluid drain. And I kept a sharp eye on the o-ring. I could have easily missed/lost the O-ring. And it was nice to know that the magnetic drum only rotated 90 degrees.

The first time I started up, the engine took about 5 seconds before it started. I didn't notice any smoke. The car ran normal after that.
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Old 12-31-11, 10:05 AM   #60
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worked great! best write up and pictures I have seen. Thanks
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Old 12-31-11, 10:05 AM
 
 
 
 
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