I want to clean my iac because im idling a little high when I first start my truck in the morning. I looked around the tb but im still not sure Im looking at the correct part. So a picture would really help. Thanks

 

I just recently cleaned mine, but I forgot to take pics of the IAC and where its located, but I did have some that you can see it.

It's the canister at the top of the picture, you can JUST see if to the left of that large rubber hose:


Here's a shot of it removed:


To clean it, I used WD-40, just spray a bunch inside those two holes, let it drain, then spray some more. Let it dry.

To get it out, you need to either remove the throttle body + adapter (and the IAC is attached to that), or you can try to get back there with a combo wrench and remove the two screws that hold it on. There also a set of wires connected to the end of that canister you'll need to unplug.

 

Okay.,I think I found it. Went out and took pictures for anybody else that needs help finding it.

 

 

And incase you want the original full size pictures.

http://homepage.mac.com/waymond/f150/liacl.jpg

http://homepage.mac.com/waymond/f150/lifarawayl.jpg

http://homepage.mac.com/waymond/f150/lir.jpg

http://homepage.mac.com/waymond/f150/liclt.jpg

 

Yeah thats it

 

Great shots! Whats it take to get the IAC off? two bolts?

Not like I have to take it off for any reason, but... I do have tools... and I am a guy... and its like one of those life long goals... to visit all 50 states... to remove every engine part... to boldly go where no mechanic has gone before!

 

I have a stupid newbie question. What is the IAC and why is it so important to clean it periodically? Flame away. . .

-Craig

 

IAC is the abbreviation for Idle Air Control. It is a valve that lets air bypass the throttle valve which controls the engine idle speed.
The PCM can control the IAC and tell it to increase/decrease the amount of air that bypasses the throttle which controls the idle speed of the engine.

Carbon deposits can be cleaned out with a shop rag or soft cloth. Do not soak the IAC valve in any liquid cleaner as it is an electrical component.

 

Basically yeah you just have to take those two bolts off.

But you'll need a long combo wrench and some patience. The bolts take quite a few turns to get off.

I decided to just remove my entire TB assembly and clean it out at the same time (about 2 cans of STP TB/intake cleaner).

 

Do you know of a good link with instructions to remove the TB assembly?

 

Um, I havent really seen any, but it is not hard actually.

You only need a 5/16 socket and a 10mm socket and a 10mm deep, along with some extensions, and maybe a wobble joint. Also, if you have a magnet stick thing, I would keep that around. And then 2 or 3 cans of the TB cleaner.

Remove the intake stuff, then (on my '97) the two throttle cables are held on with 2 5/16" bolts, slide out the two cables, and then remove the 4 5/16" bolts holding the throttle body to the adapter. Remove the two cables from the throttle body and set it aside.

Next, there are 4 more 5/16" bolts holding the TB adapter to the intake manifold (not sure if thats the correct name). One of those wouldn't come all the way out quite yet because it's pretty long. Next you need to remove the 10mm nut holding the EGR to the TB adapter, and there's a bolt on the other side, you also need to remove the 10mm bolt holding the DPFE down so that you can get past that plate. Now you'll need to get the 10mm deep and remove the bolt holding the EGR and the TB adapter together.

Now you just need to unhook the four rubber tubes (the two in the back were a pain...I ended up removing the other ends and then taking them off the adapter after I had it all out, the smaller of the 2 hoses has a 10mm bolt holding it down...you'll need to remove that).

Now the TB adapter should come out, and you can proceed to spray away with the TB cleaner. Dont forget the TB. For the IAC, the WD-40 seemed to work a little better.

Afterwards, let it all dry, then put it all back in, be careful with the bolts, dont want to crossthread them.

I think that's it.
All in all, its fairly straight forward, and it was the first time I had gone into my engine that far. Took me about 3.5 hours I think, including 3 trips to autozone (more TB cleaner, another wrench).

If you decide to get new gaskets (I would recommend a new one for the EGR at least), you can find the P/Ns in my other thread "? about IAC cleaning".

 

I just changed my spark plugs and can't get the rear COP bolts all the way in. They turn very hard and I am sure they must of cross-threaded or something. I don't want to over-torque them a break one off. I backed out one of the bolts and it looks ok so the threads must be toast in the engine block.

Im thinking about using some washers on those bolts now as the rear COPs are pretty loose. The engine runs ok now though.

 

Yeah I had the same problem with some of the bolts the second time when I went to reinstall gaskets on that adapter.

One of the damn things broke :\

Like you said, I pulled it out several times, threads were fine, and the next time, was tightening it, then POP...Only thought was "Aw *****"

But the other 3 bolts went in just fine, and the thing runs fine and everything is secure, so hopefully no problems will come out of that.

 

I usually try to start them by hand to keep from cross threading them. I must have only thought I did it on those rear bolts. My "Aw chit" was the bolt getting tight and the COP was still loose. I still have a little "Fonz" left in me that said "Don't even think about trying to tighten it anymore" with little TAP and DIE tool pictures floating around in my head. It then progressed to "How and the hell would I even use one of those tools in those rear engine locations without removing the engine!

I turned the spark plugs by hand until they got tight then I loosened them a turn or two and then pulled on the spark plug socket just to make sure I was not cross-threading the spark plugs.

Thats what I get for not working on my cars for the last 20 years. I should have stuck with doing more mechanical things.