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Cleaning IAC

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Old 07-08-2011, 08:12 PM
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rfomlover
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Default Cleaning IAC

My understanding is that when I clean my IAC, I take it off of the plenum (not sure if thats what it is called so I will call it "The thing with the horse on it" ) Then what I am going to do is clean the IAC with brake cleaner on q-tips, and then clean the inside of the hole on "The thing with the horse on it" with brake cleaner on q-tips. Any suggestions as to what else to do or do differently?
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Old 07-08-2011, 08:57 PM
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Repzard
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I spay both area out with TB cleaner.
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Old 07-08-2011, 11:28 PM
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cliffyk
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Ford says:



And that has been my experience. At best cleaning it will buy some time, most likely it will do nothing. And use TB cleaner, at least it is designed to clean intake components--oddly enough brake cleaner is for brakes...

Last edited by cliffyk; 07-09-2011 at 06:36 AM.
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Old 07-08-2011, 11:35 PM
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1998Slow 'Stang
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Originally Posted by cliffyk View Post
Ford says:



And that has been my experience. At best cleaning it will buy some time, most likely it will do nothing. And use TB cleaner, as least it is designed to clean intake components--oddly enough brake cleaner is for brakes...

I tried this on mine......did absolutely nothing.....can't hurt though, if you need a couple hour to a couple day "grace period". Just my .02
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Old 07-08-2011, 11:58 PM
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Ill probably just buy a new one. My car is so jerky in 5th and twice shut off when pressing the clutch. I want my car to be a little more reliable for Myrtle in 2 weeks.
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Old 07-09-2011, 03:37 AM
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scottybaccus
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Even buying a new one isn't a sure thing. The problem is carbon build up on the IAC pintle and the air passage it modulates. You often need to clean the interior of the intake at the IAC port. This could be a simple as swabbing the holes to clear the ports, but I have had to pull the upper intake, removing the IAC and throttle body to access all the interior passages, then I also removed more than 1/8" of carbon from the back of the throttlebody butterfly.
There is a real danger here. Dislodging pieces of carbon and allowing them to fall down the intake tract will potentially put a piece of carbon in the cylinder that the engine can't digest. I have a car in the driveway that this happened to through a similar circumstance. The carbon became lodged at the top of the piston, above the top ring. Over a period of hours it scored a groove in the cylinder wall that can only be repaired by boring the block for over sized pistons. This is an extreme case, but if you are not familiar with the IAC valve, I'll wager you aren't prepared to watch out for all the pitfalls that come with cleaning all the carbon from an intake. Get professional help or a tutor.
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Old 07-09-2011, 06:47 AM
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cliffyk
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Originally Posted by scottybaccus View Post
Even buying a new one isn't a sure thing. The problem is carbon build up on the IAC pintle and the air passage it modulates. You often need to clean the interior of the intake at the IAC port. This could be a simple as swabbing the holes to clear the ports, but I have had to pull the upper intake, removing the IAC and throttle body to access all the interior passages, then I also removed more than 1/8" of carbon from the back of the throttlebody butterfly.
There is a real danger here. Dislodging pieces of carbon and allowing them to fall down the intake tract will potentially put a piece of carbon in the cylinder that the engine can't digest. I have a car in the driveway that this happened to through a similar circumstance. The carbon became lodged at the top of the piston, above the top ring. Over a period of hours it scored a groove in the cylinder wall that can only be repaired by boring the block for over sized pistons. This is an extreme case, but if you are not familiar with the IAC valve, I'll wager you aren't prepared to watch out for all the pitfalls that come with cleaning all the carbon from an intake. Get professional help or a tutor.
That must have been one yangy old engine--I have over 80k on my TB & Plenum and they were nearly as clean as new when I repaired the intake manifold 3-4 months back. Leaking intake valves, and/or worn guides and seals can cause that.

Also from the shop manual:



Most modern fuel charging systems carry such a caution, and cleaning the TB just for the sake of cleaning it (including just spraying it with TB cleaner) can lead to persistent idle issues--though were one as crapped up as you describe I would likely clean it as well.

That said fowever, in over 50 years of repairing internal combustion engines I have never seen one that crapped up...

Last edited by cliffyk; 07-09-2011 at 06:50 AM.
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Old 07-09-2011, 07:07 AM
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just replace the IAC usually the valve is stuck inside i tried cleaning on and it didnt work either...

cliffyk- ya ive seen a couple mustang guys clean there tb and it just never acted the same...i did work on this toyota sienna it had a clogged cat and it built up so much pressure it blew oil through the pcv valve all over the tb and then proceeded to burn it on...no cleaner could take it off so i used a wire brush made it run better but the owner wanted the cheapest fix lol...by far the worst thing ive ever seen
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Old 07-09-2011, 01:07 PM
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This particular case was about 140k of city driving in Texas heat. The carbon is worse in short trips. The design of this type was really bad.
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