Throttle body and idle air control valve maintenance and testing

[Bob98SR5]

Since I'm in the engine bay anyways and have never cleaned the IACV, I decided to pull out the throttle body and clean it. Going through the owner's manual, there's some maintenance and testing you can perform on it to make sure things are in working order. More to come.

[4x4mike]

Take care when buttoning things back up. After my first cleaning I had to remove the TB and IACV three or four more times. With the RTV goop or whatever you use, use just the right amount. I was using too much or too little.

[Bob98SR5]

3 or 4 times? Dammmmmn, Daniel. I'd be pissed after the 2nd try. Did you remove the old RTV? Maybe that was it.

[4x4mike]

I removed all of the old. One time I used too much and it interfered with the turny piece, I forget what it's called. Then one time there was too little sealant. That and coolant leaks plagued me with that maintenance item.

[mastacox]

SO... any updates on your IAC valve maintenance Bob?

Just finished up a round of maintenance on the top-end of my engine including a supercharger rebuild, but I feel like my idle is crap and it could be the IAV valve is to blame. Looked through the FSM and there are test procedures for the sensor but didn't see anything about cleaning the valve; maybe I missed it?

[Bob98SR5]

Brian,
Yes aside from 1 morning, it's working flawlessly. Idle from cold start is around 1700, but nicely settles down to 700 after warmed up. Looking through my manual, I didn't see anything in great detail about cleaning the IACV other than to clean it with a cleaner. If I were to do it again, I'd definitely use a q-tip or the like instead of bombing it with cleaner. A little more gentle for me next time.

The odd thing was I believe the IACV stuck, so I ended putting a few drops of machine oil down near the vane edges. No problems since. Perhaps it was too dry from all the carb cleaner I used?

[mastacox]

Good feedback, I'll have to take a look and clean things out with q-tips and some carb cleaner.

[YotaFun]

Don't mean to hijack.
I see the words carb cleaner getting used a lot here.
CNC makes a Throttle Body Cleaner that more specific for today's engineering over the Carb cleaner that is a little more harsh.
That might give you different results.
I have see how carb cleaner affects plastic over the throttle body cleaner so the carb cleaner could be causing an issue.

[Bob98SR5]

Good feedback, Avi

Brian, the other thing I wanted to advise is to remove your TPS sensor before cleaning the throttle body. I believe I may have fouled it up by getting cleaner in there. Maybe. There's no special setting or alignment for removing and putting it back on. All I know is I didn't and my idle was way too high and would not settle. This is even after bench testing the IACV after placing a drop or two of oil to make sure it worked.

[mastacox]

Thanks Bob I was able to do basic cleaning with the throttle body on the engine, seems to have helped but the real difference was re-adjusting the throttle and transmission kickdown cables. Bolting it all back together I think I didn't get the tension right for all the cables.

[Bob98SR5]

brian,

that reminds me, i need to do the same on the cable. I think there's a wee bit of slack on mine. when i'm going up hills i feel like there's something a little missing and the slack on the throttle cable is the culprit.

[YotaFun]

If you guys figure this out that would be awesome but I think the slack is built in.
All 3 of the 4runners I have (well 2 now) have that little bit of slack, even after doing the frame swap (where I had to disconnect those lines) I still haven't been able to get the slack out of the throttle. -_-