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Guest Message by DevFuse
 

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IAC cleaning procedure wanted


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19 replies to this topic

#1 davebugs

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Posted 16 April 2009 - 04:07 PM

I searched here and endwrench(where I rarely have success searching) looking for a procedure.

Anyone have a link handy?

I have a car that cuts out for part of a second just off idle - especially when cold. I've never had to clean an IAC before. I may take one of a parts engine and clean it ahead of time. Actually I have ones that I know don't stumble to replace it with but might as well clean it while it's in my hand.

Debating how much of the unit needs removed/cleaned, etc.

Pics would be great.

#2 ericem

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Posted 16 April 2009 - 05:47 PM

There is a hose going to the unit. Just spray some IAC, carb cleaner, throttle body cleaner w/e cleaner in there and hold the throttle open when you do this, it should definitely help. Do you know where your IAC is? What year and model is your car btw?

#3 davebugs

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Posted 16 April 2009 - 05:54 PM

This is a 95 2.2 in an OBW that I transplanted.

You mean the stiff hose that goes to the airbox that if you forget to connect it the car immediately dies correct? Almost a foot long.

I do have ones here on parts engines that had no hesitation. So I could swap if that made sense.

Just spraying - engine running or off? I'm assuming off since if it's the hose I'm thinking of the car will die with the hose disconnected.

#4 ericem

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Posted 16 April 2009 - 06:01 PM

On the 2.2L i have I know it connects to the intake not directly to the airbox, the hose is like a couple feet long and yes it does die when you remove it. You can do either way, with the engine on, just hold the throttle via the throttle body, or off and just fill up the hose.

#5 Olnick

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Posted 16 April 2009 - 06:17 PM

I suggest taking it out of the car to clean. There are (IIRC) 3 bolts, one of them is hidden underneath but you can find it with your fingers! One air hose and one small coolant hose to disconnect.

When you have it out, take off the gray plastic top (2 phillips screws) then you can give it a good spray cleaning. Makes me feel so much better to watch the gunk flow out!

#6 fleming442

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Posted 17 April 2009 - 04:02 AM

I did mine on my 2.5; is it different than the 2.2? Point is, no hose involved. I just took a couple of bolts out and unplugged it. I used 3M Throttle Plate Cleaner to remove the gunk on the plunger and the seat in the intake.

It almost sounds like you guys are talking PCV.:-\

#7 davebugs

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Posted 17 April 2009 - 06:40 AM

I'll look today. I haven't seen a pic of the IAC yet. But the PVC is easy.

I think we're talking about the gizmo basically under the PCV - but I could be wrong. I started pulling one of a 96 2.5 parts engine yesterday because I had easy access but never got it off. Ran out of time. I had some assistance with garage cleaning (read engine stacking).

I'll probably remove one from one of the 97 2.2's that I have to put on the 95 2.2 having the issue.

#8 wtdash

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Posted 17 April 2009 - 09:56 AM

Pic of IAC (thanks Legacy777):
Posted Image

And a cleaning method from HERE:
Dirty IAC valve.

The procedure has been posted a couple times on other sites, but in short you have carbon dust build up that is making the idle controller stick. Easiest way to clean:

Remove pcv valve
Remove top (electronic portion) of IAC
Remove hose for the IAC at the intake side
Fill hose with plenty of carb cleaner, while turning the valve
Fill the tube again and this time blow while turning, air and cleaner will escape through the PCV valve hole

Repeat as needed. You should feel ZERO drag when turning the valve. Reassemble and try it.

#9 porcupine73

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Posted 17 April 2009 - 10:03 AM

For the traditional cable throttle soobs (before drive by wire), the IACV was in this position before about '99-00:

Posted Image
Posted Image


Then around 99-00 Subaru switched to speed density based setup (cheaper) and did away with the MAF and the IACV is here. This is the setup the endwrench article talks about.
Posted Image


Then what in '05 it went to drive by wire so there is no separate idle air control anymore; it simply controls the throttle butterfly for the idle.

I don't know, I do not remove the IACV's just because of the gasket issuse etc. I let them aspirate some throttle body cleaner and that has been working ok for me, maybe not as thorough as removing to clean it though.

#10 fleming442

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Posted 18 April 2009 - 12:34 AM

Porc, I do not doubt your knowledge. The bottom pic is what I have. However, in the 3rd to last pic, I believe that to be the EGR, no? The IAC looks to be to the left of the PCV. Just my .02

Edited by fleming442, 18 April 2009 - 12:36 AM.
wrong pic siting


#11 porcupine73

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Posted 18 April 2009 - 07:34 AM

Do you mean the pic of the 2000 Outback? That's the IACV as it is shown. That engine at least with auto trans does not have EGR. Here's a pic of the IACV intake on the 2000 Outback with the air filter and filter housing removed. It's the small hole at the top in front of the throttle plate:

Posted Image

#12 fleming442

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Posted 18 April 2009 - 09:31 AM

Gotcha. Yes the 00 OB pic. Upon further inspection of the other pic , I can now see the IAC (little blurry last nite- got deep in the cups). Most of the time I'm half talking out my azz, but going off general IC engine knowledge.:D

#13 davebugs

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Posted 19 April 2009 - 12:04 PM

Thanks for the pics. That is what I started to remove from the 2.5 and was planning on cleaning and installing on the 2.2. The 2.5 was on the ground so I couldn't see that elusive 3rd bolt and jus tput the engine on the shelf.

Now it sounds like the 2.5 and 2.2 aren't interchangable anyways.

Perhaps this is tonights project.

#14 davebugs

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Posted 21 April 2009 - 08:20 AM

I'm gonna try cleaning it on the car today. Car is sold and for the first time I let some one widdle me down a little bit on price.

I was gonna put plug wires, HVAC bulbs, and remove and clean the IAC - of course they didn't know that. So now it won't be happenning. You literally get what you pay for.

Thanks for the pointers and pics.

I reread the thread and don't fully understand the pointers. But I'll remove the hose that goes to the airbox, get the airbox outta the way. Then decide whether to leave the hose on or not when spraying the carb claner. I know the car won't run more than a few seconds without this hose connected.

If it makes sense I can remove the plastic top with the few screws and clean it off a bit.

The symptoms I'm hoping to improve on are mostly the delay/cutout just off idle when you're easy on the pedal. Also it doesn't run real smooth at low RPM's. No CEL's after a couple hundred miles. It should be smoothing out by now based on past experience.

If anyone has any other recommendations now that I'm unlikely to remove it for cleaning please chime in.

o.k. last edit wasnt saved.
My reason for cleaning this is stumble off idle when pedal is gently pressed, doesn't run smooth at low RPM"s - idle through 1k. No CEL's. 200 miles on this engine so passed experience tells me it should be settling down. If there is something else to look at please mention it. New plugs, has aftermarket wires that aren't new.

Edited by davebugs, 21 April 2009 - 08:46 AM.


#15 89Ru

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Posted 11 July 2009 - 05:30 PM

Pic of IAC (thanks Legacy777):


And a cleaning method from HERE:
Dirty IAC valve.

The procedure has been posted a couple times on other sites, but in short you have carbon dust build up that is making the idle controller stick. Easiest way to clean:

Remove pcv valve
Remove top (electronic portion) of IAC
Remove hose for the IAC at the intake side
Fill hose with plenty of carb cleaner, while turning the valve
Fill the tube again and this time blow while turning, air and cleaner will escape through the PCV valve hole

Repeat as needed. You should feel ZERO drag when turning the valve. Reassemble and try it.


Thx for the procedure. Wouldn't have touched the IAC without it.

Take care when removing the top portion of the IAC, the valve is driven by a magnetically coupled shaft that is brittle and its top can shatter if the housing comes off at an angle. The housing should come off straight vertically, not easily done since the housing is secured into a channel in the valve base, don't know with what, some type of glue.

Just my 2 cents.

Here's a pic with the shaft top buggered...still works tho after de-chipping

http://i444.photobuc...ru/P1040145.jpg

Edited by 89Ru, 11 July 2009 - 05:51 PM.
add pic


#16 1-3-2-4

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Posted 21 August 2011 - 04:05 PM

Pic of IAC (thanks Legacy777):
Posted Image

And a cleaning method from HERE:
Dirty IAC valve.

The procedure has been posted a couple times on other sites, but in short you have carbon dust build up that is making the idle controller stick. Easiest way to clean:

Remove pcv valve
Remove top (electronic portion) of IAC
Remove hose for the IAC at the intake side
Fill hose with plenty of carb cleaner, while turning the valve
Fill the tube again and this time blow while turning, air and cleaner will escape through the PCV valve hole

Repeat as needed. You should feel ZERO drag when turning the valve. Reassemble and try it.


Any clue where the coolant line on the right side of the IAC goes? From the IAC where does the hose go?

#17 wtdash

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Posted 21 August 2011 - 05:43 PM

Any clue where the coolant line on the right side of the IAC goes? From the IAC where does the hose go?


It goes to the coolant crossover pipe. See it here...it's that black hose in the upper middle of the pic (this is an EJ25 crossover, but should be the same as the EJ22). I labeled the other end, too:
Posted Image

Edited by wtdash, 21 August 2011 - 05:51 PM.


#18 1-3-2-4

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Posted 21 August 2011 - 06:23 PM

uhmm lets make sure we are on the same page.. here is where I'm stuck

Posted Image

I don't see anything near by where the coolant line hooks into.. I know it's gotta be some place given the short length of the hose..

*edit just saw your edit.. Oh man.. I hope I don't have to lift the intake manifold again for that.. I just put on new gaskets..

#19 wtdash

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Posted 21 August 2011 - 06:28 PM

*edit just saw your edit.. Oh man.. I hope I don't have to lift the intake manifold again for that.. I just put on new gaskets..


If you remove the IAC, You 'should' be able to access the crossover connection.

#20 1-3-2-4

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Posted 21 August 2011 - 07:44 PM

yep got it thanks! lol good I did that I forgot to plug up the CTS and the one for the gauge.

now gotta do the heater core lines and one more bolt for the transmission and the fuel lines and see if she starts :D




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