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Someone reporterd recently after having cleaned the IAC valve.

I remember he said to watch out for flying spings when separating the electronic part from the mechanical part of the valve.

He also said that after plugging all holes with duct tape he filled the valve with cleaner and let it soak for a while.

He finally said that after that his idle had never been smoother.

All I remember. Maybe that very person will chime in.

Good luck!

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The manual has the procedure for cleaning the IAC valve. In short, it says to disconnect the IAC air hose from the intake duct, keep the engine speed at 2000 rpm and spray the cleaner into the hose. The Subaru manual specifically calls for GM cleaner and gives a part number.

Also, a new IAC valve would cost at least $300. Inside it has two solenoids whose duty cycle is controlled by ECU. So this may be a good time to get a $20 manual from techinfo.subaru.com.

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I have two problems with that procedure AVK.

1) Never could get the GM cleaner from a GM dealership. Bad luck maybe.

2) I was under the impression that the IAC only is open when the throttle is shut (engine indling). Would air be sucked into the valve at 2000 rpm. (throttle partly open)?

Has someone here used that procedure?

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frag: I didn't need to clean the IAC but only read about it as a possible preventive maintenance item. I don't know what the actual IAC control algorithm is. Could it be that it stays partially open at all times? The GM cleaner should be available mail-order under Delco name.

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i had no trouble getting a can of the gm top engine cleaner from a gm dealership. i never did get a chance to use it yet. in the service manual, it seems to show the cleaner as a spay can, but what the dealership sold me was just a bottle.... i cleaned out my throttle body and that seemed to solve most of the hesitation/throttle problems i was having...

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Ahh, I am here. I'm the one that recommended brake cleaner...

 

However, what exactly leads you to believe that it needs cleaning? If your IAC valve is stuck closed, it will not idle. It will only stall. If it's stuck open, you're going to basically haul rump roast, once you even nudge the throttle...

 

My personal opinion is that the IAC valve as well as the throttle body are best just left alone. You can easily make things worse by trying to make them better...

 

Anyway, I used some crappy carb cleaner in mine and caused it to seize closed, so $360 later, I put a new OEM one in... Yes it hurt. I definitely learned my lesson...:banghead:

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SUBYLOVR, I asked you this question in another thread that probably you did'nt read. Why could you not free the valve using this time a cleaner that does'nt leave a residue? How can something get so gummed up that nothing will be able to free it? Just want to understand in case I decide to clean mine.

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Subyluvr

My engine will start and run fine, but when I shut it down before it get's totaly warm it will stall. I then have to feather the gas to keep it going till it warm's up. I started to take the valve off and found it to be really tight place to work so I sprayed carb. cleaner up the biggest hose. Can't tell that I hurt it are helped it. (how much was the labor to have the valve replaced.) I know the valve cost's around 300.00. If you done your own labor how many bolt's and hoses are holding it.

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Frag, sorry I didn't respond in the other thread. It's possible that spraying a better cleaner in a gunked-up IAC might free it up. But I did this in the wintertime, and with the valve stuck closed, the car would barely start. So I bit the bullet and bought a new one. Had circumstances allowed, I might have taken a little more time to fiddle with it and possibly fix it, instead of blowing a whole paycheck on a new one:brolleye:...

 

TC, spraying anything in the big hose won't do any good unless the engine is running and idling. And pulling the hose off creates a large vacuum leak, which will not allow the engine to idle correctly, so you would have to plug that hose, while spraying stuff in the valve. But again, if you do this, I would suggest using a small amount of brake cleaner, not enough for your engine to choke on. The reason is that brake cleaner evaporates and leaves behind no residue...

 

I replaced mine myself, and while it's not a all-day job, it's not fun. You will have to remove anything PCV-related in the area to get to everything, disconnect the wire and unbolt in from the intake manifold, and then for the fun part: getting the coolant hoses off of it. The valve needs the engine's operating temperature to function correctly, so it has to have coolant going through it. These hoses are very small and hard to reach. Getting the old valve off the hoses isn't all that bad, just twist and pull. But putting the new ones on takes a little more patience...

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Subyluvr

Was your engine a 2.2 ? How many mounting bolt's were on your's I took two off of my 2.2 and it still would not come off. Also they were not real tight and I could not find the torqe valve for them so I did not retighten them to tight in fear that they might break. If their is mounting bolt's below the two I took off it looks like the intake manifold might have to come off to get to them. Did you has to have long needle nose pliers to remove clamps or did you remove them after removing valve from manifold? I appreciate all of the help already, and any more you could give would also be appreciated.

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Yep all 90-94 Legacies were 2.2 ...

 

TC, yours might be a tad different from mine. 90-94 Legacies has a difference in IAC valves depending if the car was AT or MT. The AT's had a rotary type valve, while the MT's was a shutter type I believe... All 2.2's past the 90-94 Legacies, regardless of tranny, got the rotary, I have the shutter-type...

 

Anyway, there are four bolts that hold the valve to the intake manifold, sorry forgot to mention that. I believe the two up top are longer than the two on the bottom, so watch your bolt lengths when you put it back on... You don't have to remove the intake manifold, nor do you want to. That's a FAAAR more complicated process than you think it is!!!

 

I had difficulty doing it, but yes I used needlenose pliers to get the coolant hoses loose enough to come off... I would say try to move the clamp back off of the valve nipple, but the hose is so short, it might just make things even harder...

 

Keep shooting if you got any more questions... I know more about this than I really want to :brolleye:

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Thank's

I can tell it want take long to get plenty of this. I will wait until I get the new part and a few day's off an I will take much more stuff off and out of the way. I could not even see the bolt's on the bottom much less get a wrench on them.

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