yeah having those coolant lines disconnected will make it run at a higher rpm.

I'm not sure what your talking about with the adjustment. If your speaking of the actual electrical connector i removed, it just picks up a magnetic signal and when the motor warms up the IAC will apply voltage to one wire and it will turn the inside to one side or the other.

I dont think there is any adjustment.

One thing I do know is that if you can somehow jam the inside to one side it will idle really low (600rpm). I know this because the IAC I just replaced on the 92 XLE was carbon stuck to one side and it idled like that. After it warmed up there was no problem

 

yeah having those coolant lines disconnected will make it run at a higher rpm.

I'm not sure what your talking about with the adjustment. If your speaking of the actual electrical connector i removed, it just picks up a magnetic signal and when the motor warms up the IAC will apply voltage to one wire and it will turn the inside to one side or the other.

I dont think there is any adjustment.

OK in this picture the two screws with the red/orange paint on them MAY BE adjustable - just a theory on my part, looks like the valve can be opened/closed to some degree - may be wrong on this though:

 

eh, I dont think theres any adjustment . The FSM Indicates Continuity and voltages for the IAC and shows taking it off and re-installing it but doesnt say anything about that particular piece.

You never know, it may just do something

 

OK we'll have to remove it tomorrow and make an adjustment and see what happens...if anything...will keep yall posted

 

sounds good

 

Mine is a 5SFe and AjKalian is right. You can adjust the IAC. I found this out earlier when I actually royally screwed up my IAC cleaning project. I stripped off the Philips screws, broke the throttle body bolt and could not get off the coolant lines. In this whole mess I also managed to screw up my idle.
However I removed the two screws in post#3 picture above and moving the cylinder pivot by hand I was able to bring down my hot idle.
Cold idle hovers around 1000 RPM after settling down(high by 250 rpms)
Hot idle around 750. (after a couple of minutes of freeway driving)
So I dunno how but I am able to play with my idle which is cold screwy right now!

 

Excellent! THat's what I thought it was from the pictures - it's a thermostat of sorts which is adjustable. Other IACs should be similar in design to your 2000 model, V6 or otherwise. Will post a DIY this afternoon...Thanks for the nice pics!

 

This stuff will make you crazy

I did some testing on the IAC valve by applying 12v to the leads as outlined in the FSM. What I found out is that when the valve is opened, moving the plate on the end of the IAC doesn't do too much. But when the current is applied to close it, it doesn't close all the way. Maybe a .025" gap but the gap can be closed by rotating the plate. Maybe there is supposed to be a gap, IDK.

The other wild card is that the spring might some sort of a thermal spring, that changes tension when it heats up. If so, then the tension could be different depending on whether the engine is cold or warm and the gap could be adjusted depending on the temperature.

And to make matters a bit more confusing, the terminology referring to the terminals is different if you have a 4cyl, or a 6cyl. And to make it even more confusing, there is a typo in the 6cyl instructions. Easy to figure out, but try telling someone to test the IAC by reading them the instructions as printed in the FSM.

 

hmmm . Thats neat to know

 

Hmmm....

I know there is supposed to be some kind of gap - that's how the IAC works, but as to how large the gap is and when it should be receiving power/not receiving power - I will simply adjust it and see what happens.

Could theoretically make it MORE adjustable by removing more metal off of that plate but we'll see what happens this afternoon first...

 

Interesting! Yeah, that coil def looks like a bimetallic spring; a temperature sensor. And it looks like it's bathed in coolant, so it would rotate that gray "cup" in the center with the bowtie-shaped cutout, which looks like it would alter the range-of-motion of the shaft in the center. It sure looks like a way to adjust idle RPM, but in what manner?... Hot only?... cold?... both???

 

If I were you I would adjust it more to the HOT side. If the cold side is more opened you will get a higher RPM at idle. over more to the hot side It will idle lower where you want

 

Great thread guys...BTW I could adjust both hot and cold idle. In fact you can disconnect the IAC connector and with the car running turn the circular pivot either way.
Keep turning the pivot shaft (obviously circular motion!) with the engine running. Keep doing this until you pull out the IAC connector and the engine should stumble and shut off.
This is how I have set my idle right now.
And Perkins is very correct in post #14 above. I have done this on a fully warmed up engine. On a cold engine this procedure resulted in a vacuum leaks of sorts!

 

Now this is really getting interesting

My hunch that the spring might be thermal related turned out to be correct. Why else would they use a brass spring, compared to the normal blueish spring steel. To confirm that I put the spring in a pan of water and put the pan on the stove and sure enough it moved when heated.

So I decided to make a video of it. Sorry the video is not upright, but I couldn't figure out a way to rotate it.

You can see in the first part of the video how as temperature rises the spring rotates. I had to give up taking the video at about 150 degrees, because it got a little hot holding the camera right above a pot of boiling water.

But after the water got to boiling I took a close up pic of the position of the the spring.

The last part of the video is when I poured some cold water into the pan, and you can see the temp drop and the spring return to the 12:00 position.

How much more complicated could they make this thing. You have two coolant lines going to it. There is a vacuum line in the Calif models. There is a magnetic motor that turns the valve. Now I come to find out that there is a spring that when heated changes the position of the valve. If I can find my geiger counter, I'll bet some part of that valve is radioactive and emits gamma rays to be picked up and processed by some other overly complicated system. :lol:

.

 

Yeah, this IAC design is probably the dumbest I've ever seen. The ECU has all the information (air temp, coolant temp, engine RPM, load, etc), so a stronger stepper-motor controlled IAC would be better.

The picture in message #7 shows the newer style IAC. Just leave out the gray cup thing and let the ECU do the calculations. The gray cup only changes idle speed I think at the cold extreme. When it warms up the ECU does all the calculations.

Just make sure there are no air leaks from the bi-metal spring lid or the magnetic motor :lol: side.

My hunch that the spring might be thermal related turned out to be correct. Why else would they use a brass spring, compared to the normal blueish spring steel. To confirm that I put the spring in a pan of water and put the pan on the stove and sure enough it moved when heated.

So I decided to make a video of it. Sorry the video is not upright, but I couldn't figure out a way to rotate it.

You can see in the first part of the video how as temperature rises the spring rotates. I had to give up taking the video at about 150 degrees, because it got a little hot holding the camera right above a pot of boiling water.

But after the water got to boiling I took a close up pic of the position of the the spring.

The last part of the video is when I poured some cold water into the pan, and you can see the temp drop and the spring return to the 12:00 position.

How much more complicated could they make this thing. You have two coolant lines going to it. There is a vacuum line in the Calif models. There is a magnetic motor that turns the valve. Now I come to find out that there is a spring that when heated changes the position of the valve. If I can find my geiger counter, I'll bet some part of that valve is radioactive and emits gamma rays to be picked up and processed by some other overly complicated system. :lol:
.

 

Thanks AjKalian, you are a very inquisitive science student
IMHO this disproves the FSM's claim that idle is not adjustable in camry's (especially 5SFEs).
Also I remember someone on TN saying he could adjust his 5SFE idle using the Throttle Posistion Sensor (aka TPS). I think I may have messed up my TPS also, stupid me I opened the TPS just to supposedly "clean" it up. To my chagrin I found there's nothing to clean!
I screwed the TPS back to the throttle body but I guess its gone out of alignment. Is it possible? Has anyone tried this?

 

IMHO this disproves the FSM's claim that idle is not adjustable in camry's (especially 5SFEs).
Also I remember someone on TN saying he could adjust his 5SFE idle using the Throttle Posistion Sensor (aka TPS). I think I may have messed up my TPS also, stupid me I opened the TPS just to supposedly "clean" it up.

When I removed the Throttle Body and the IAC for cleaning the first time I did this, I screwed up the idle too. I looked on the throttle body and saw the adjustment screw, and figured it worked the same as a carburetor. So I adjusted it when the engine was warm, but the next day when I started it up the idle went to like 2,500 and stayed there.

I figured it was time to read the instructions.

Once I did this procedure, the idle worked as it should, both for cold starts and when warmed up.
==============================================

1. INSPECT THROTTLE VALVE
(a) Apply vacuum to the throttle opener.
(b) Check that there is no clearance between the throttle stop
screw and throttle lever when the throttle valve is fully closed.

(Note: The "Throttle Stop Screw" I thought was the throttle adjusting screw.)

2. INSPECT THROTTLE POSITION SENSOR
(a) Disconnect the sensor connector.
(b) Disconnect the vacuum hose from the throttle body.
(c) Apply vacuum to the throttle opener.
(d) Using an ohmmeter, measure the resistance between
each terminal.
Fully closed VTA – E2 0.2 – 6.3 kW
Fully open VTA – E2 2.0 – 10.2 kW
...............VC – E2 2.5 – 5.9 kW

(Note: This is a very wide range, so I just picked something in the middle.)

(e) Reconnect the vacuum hose to the throttle body.
(f) Reconnect the sensor connector.

3. INSPECT THROTTLE OPENER
(a) Allow the engine to warm up to normal operating temperature.
(b) Check idle speed. Idle speed: 700 ± 50 rpm
(c) Disconnect the vacuum hose from the throttle opener, and plug the hose end.
(d) Check the throttle opener setting speed. Throttle opener setting speed: 900 – 1,950 rpm
If the throttle opener setting is not as specified, replace the throttle body.
(e) Stop the engine.
(f) Reconnect the vacuum hose to the throttle opener.
(g) Start the engine and check that the idle speed returns to the correct speed.
==================================================

So I don't think you can "adjust" the idle speed in the traditional sense. You might be able to change it by experimenting with the fully open/closed values in the TPS. BTW, the above procedure was for my 6cyl, it might be a bit different for the 4cyl.

But I'm betting Mr. Perkins will know the answer for the 4cyl motors.


.

 

If the IAC is as i said in my previous post, this is about how it should idle:

Also ...

@ ajkalian

I think that the vacuum line is on both federal and Cali. all my cars are federal and all four have a vacuum line and two coolant lines

 

I think that the vacuum line is on both federal and Cali. all my cars are federal and all four have a vacuum line and two coolant lines

Hmmm, that's interesting for a couple of reasons. When I was reading your DIY on the IACV I noticed that they were different. I just assumed it was because of some stupid Calif regulation. But if yours all have the vacuum tube, then why are they so different. I can't see how a 6cyl slot would need to be any larger than a 4 cylinder slot. I took one of your pics from the DIY and compared it to the 6 cylinder valve in my car. You can see that the slot that the valve rotates in is quite a bit larger than the one in the 4 cylinder. I wonder why??

And I guess the last question is what purpose does the vacuum line serve, other than to crud up the inside of the valve? The valve is turned by the magnetic motor. The spring on the end is thermally sensitive, and it controls the position along with the motor depending on the temperature. So where does vacuum come into this equation. I haven't removed the line to check, but I'm betting it isn't vacuum at all, rather crankcase blow-by. And then you have to ask the question, why dump oily crankcase gases into an already overly complicated valve system?

 

IT'S FIXED!!!!

Turns out that it IS adjustable as I had suspected by loosening the two small screws and doing some experimenting. First pic is where I started from...looks like it is close to midway between stops:

I first tried to turn it counterclockwise to its full CCW travel so it looked like this:

When I did this idle speed jumped to 2000 RPM and surged between about 1600 and 2000RPM with the computer (I guess) trying to compensate for too fast an idle. So I turned it the opposite way to full clockwise travel, and idle went to 750 RPM on the dot!

If you do the "remove-coolant-lines-to-IAC" mod then you will likely need to turn this adjustment plate FULLY CLOCKWISE for normal idle in colder weather - like so (I just inverted the picture here guys):

HOWEVER, I have no idea how it will idle in the summer months We shall have to wait and see

@ ajkalian

I monkeyed with the TPS last year and it took a little fiddling to get it back to where it wouldn't throw a code every week or so. But, I also have the MAP sensor enhancer which I'm sure complicated things with the computer as well. Works well now! My gas mileage is acceptable for now and power is, well, it's a 5SFE so what do really expect outside of a turbo or S/C:lol:

 

Thats awesome man. You should add that to the 5sfe IAC Removal DIY :thumbsup:

Or just write your own DIY

DIY: IAC Fine Adjustment or something . lol

 

Thats awesome man. You should add that to the 5sfe IAC Removal DIY :thumbsup:

Or just write your own DIY

DIY: IAC Fine Adjustment or something . lol

I would but I'm not sure how to go about doing it...if you would like to copy and paste it to your DIY feel free - I'm sure someone will need it down the road at some point!

 

^^ lol

I added it to my DIY. I just quoted you
http://www.toyotanation.com/forum/showthread.php?t=361673

 

You guys are awesome Mister Perkins, N/A Camry Sleeper and of course AjKalian...Its only and only coz of TN that my 16 year old 174K miles car drives like new. No Kidding.
Where is the NightTime thread janitor aka LynchburgCSI? Can you please sticky this in the DIY section. Many guys screw up their idle while cleaning the IAC. This will benefit the spooked out and pissed souls...ha ha

 

See, if people want threads like this stickied, they should add it to my "add this to the sticky" thread!

http://www.toyotanation.com/forum/showthread.php?t=359953

Good info here. It may need to be cleaned up a bit though.

 

Also when I manage to get around to using the 1MZ 60mm TB on the 5SFE (50mm) in the next several months, I will have to adjust that one as well. It will be interesting to see how and if it's possible to adapt the larger TB to work - I love the challenge though:thumbsup:

^I'll bet that the IAC uses a vacuum input signal that corresponds to MAP voltage somehow that allows constant idle speed regardless of ambient and engine coolant temperature - for maximum fuel economy I am guessing.

 

Also when I manage to get around to using the 1MZ 60mm TB on the 5SFE (50mm) in the next several months, I will have to adjust that one as well. It will be interesting to see how and if it's possible to adapt the larger TB to work - I love the challenge though:thumbsup:

I bet it will fit, You might have to modify the inlet on the plenum but its definitely possible

You could always make an adapter plate for the TB to accept the 60mm TB like this thread:

Its a ford, but you get the picture :thumbsup:
http://www.taurusclub.com/forum/87-engine-drivetrain/142730-60mm-tb-upgrade-vulcan-motor.html

 

Is that the Air Assist hose you guys are talking about? It's just to help bring air next to the injectors to help fuel atomize for emissions reasons.

 

i m nearly 10 years late to this topic i guess. i have same issue like you. revving high when i start up. so i pulled out IAC including the motor and gave it a good clean..it now spins freely but what i forgot to do was i forgot to make a note of how the motor thing with screw was originally set at factory. so i m now struggling to find the sweet spot. my question is when you adjusting the IAC, should i wait till the engine is fully warmed up before i adjust the idle and what should the ideal idle be when i set it? should i set this with accessories like A/C on? if i set the idle while the engine is warmed, then how does that impact my cold start rpm? many thanks