Toyota Nation Forum banner

21 - 33 of 33 Posts

·
Registered
Joined
·
688 Posts
Discussion Starter #22
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!
 

·
A camry n00b
Joined
·
390 Posts
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
 

·
イリジウム
Joined
·
11,652 Posts
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:
.
 

·
2001 Camry XLE 1MZ-FE
Joined
·
1,620 Posts
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?
 

Attachments

·
抵抗は無駄で&#
Joined
·
9,079 Posts
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
sorry, but that's not entirely true for 4 cylinder 5s-fe models since 2000. statements like those make people search for something that don't exist and no one really will tell them they don't have it (on specific models, like my ''00 5s-fe solara).

that vacuum line on IAC (for Air Assist used on California specs heads) has been removed from the design and fuel injectors have been upgraded to compensate, starting with 2000 camry/solara 2.2L.

I have no idea about gen3 designs in that matter though.
 

·
Turbo Snail
Joined
·
5,300 Posts
I have no idea about gen3 designs in that matter though.
All generation 3 camrys have them. All of the information I provide regarding camrys are usually for the 3rd generation camry as I am more familiar with their design

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?


.
The valves are a different design because the one is a 4cylinder and the other is a 6cyl :D. You have 2 more cylinders, so it must be designed like that to compensate for the added cylinders. (Just guessing).

The IACV is an electrically operated valve that, on commands from the engine-control computer, varies the size of an air passage that bypasses the throttle plate of an electronic fuel-injection system, thus controlling idle speed. The vacuum line is simply what it is .. A Vacuum line. (On the 5sfe anyways). It runs to the copper tubing behind the Intake and runs to a pressure regulator thats electronically controlled. Then it is diverted to the Intake manifold Gas Filter (Hose right to the side of where the MAP sensor vacuum hooks into. I really dont know why its there, but it does serve some purpose. If you look at the Kens Update thread, I list a 5sfe Federal Vacuum Routing for the 3rd gen camry, and you can clearly see where the IACV Vacuum line runs to.

http://www.toyotanation.com/forum/showthread.php?t=360388
 

·
Registered
Joined
·
688 Posts
Discussion Starter #30 (Edited)
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.
 

·
イリジウム
Joined
·
11,652 Posts
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.
 

·
Turbo Snail
Joined
·
5,300 Posts
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
 

·
Registered
Joined
·
2 Posts
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
 

Attachments

21 - 33 of 33 Posts
Top