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How to: IAC valve cleaning thread (w/pics)

karl_burns

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Have you ever noticed a loud hum and/or whine (whining) coming from your engine bay? Or more specifically your intake area? Or does your engine have a hard time holding the idle? Well, more often than not, this is due to a dirty IAC Valve. Since everyone is always asking about it, hopefully this will help.

My engine was making the loud hum / whine noise. AutoZone wanted $131.99 for a new part. and it's $50 deductible against my extended warranty, so I wanted to fix this myself. I purchased a can of Electrical Parts cleaner, the non-residue type, drove home and let the engine cool. Here's a pic of where the IAC Valve is located under the hood:
3661iac_before_low_res.jpg


Two 10mm bolts to remove, and unclip the electricals:
3661iac_removed_low_res.jpg


Here's the dirty intake's connection with the IAC:
3661intake_connection_low_res.jpg


Turn the valve to notice two chambers. Inside one of them you will see a spring. Inside the other, you will probably see a bunch of dirt coating what should be an exposed sensor. Spray the Electrical parts cleaner liberally, directly into the opening, and watch until the liquid coming out of the valve is clear (white). Set the IAC on a towel or clean surface and allow any other liquid to drain and the sensor to fully dry. Here's a picture of a clean IAC valve (underside):
3661iac_after_cleaning_low_res.jpg


And don't forget to clean the sensor below the black snap off cap on the side of the IAC valve:
3661iac_sensor_after_removing_black_cap.jpg


After allowing to dry, replace the IAC and start your truck. You should allow the engine to warm up for a few mintues and the computer will re-learn how much air to allow into the engine at idle.
I experienced a much LOUDER whine after doing this for the remainder of the day, but I only allwed the liquid to drain for about 2 minutes. The whine hasn't returned in two days since, so I'm guessing the liquid cleaner wasn't completely drained when I replaced the IAC Valve. Just a warning in case you are anxious like me.

Karl

CBOUG76.... can I be on the Useful Threads list?
 


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Opera House

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What!!!!! You didn't take off the plastic cap

The outside black plastic cap that easily spins will pop off and snap back on without damage. Inside there is a felt filter pellet. Cleaning just the valve without removing this often cloggs this filter up worse. This source of back air flow balances the valve and provides clean air to prevent buildup on valve. Often just cleaning this will get rd of the moose calls. Add pictures of this and you have something.
 




drmoore71

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karlito, i am so proud of you! you got your hands ditry! now i need a moment to wipe the tear from my eye. you do know, however that not allowing the cleaner to drain completely could have led to an incendiary situation, though.
 








karl_burns

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Ooooooohhhhh

Now that I know it spins off, I'll check that tonight. Mine wasn't coming off easily, so I didn't press my luck.
I'll append my post with pics of that.
Thanks Opera House,
Karl
 




Jason_25

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It doesn't spin off, it just pops off when you pull it outward.
 




williecume

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i think i'll try this saturday, i'm getting tired of the whining also.
 




karl_burns

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I updated to include the black cap

Didn't look like much in there, but went ahead and sprayed cleaner on it as well. Allowed to dry for almost an hour, so hopefully I don't get that same 100 db whine I got when it was still wet Saturday!
At least it went away, and I didn't have a date that night.....
<Don't even think about flaming me Doug>

Karl
 




drmoore71

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and I didn't have a date that night.....


NO DATE?!?!?!? are you losing your touch?
 




Opera House

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Arrrrgh This is a tough crowd to please

But, that plastic item is two piece. The outside plastic cap snaps off the inner plastic piece which stays on the IAC. Between these two pieces is the felt filter pellet. Interesting how much sand makes its way up there.
 




MaverickDaKid

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Sorry I'm not that smart when it comes to mechanics but... what is that thing under the IAC called. It has 2 tubes leading down somewhere in the engine and has an electrical socket aswell?
 




X~FACTOR

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I noticed you have a '98, karl. I have a '97 with 60k miles and have not experience this problem at all [knock on wood]. What mileage does this normally occur?

Very good write up btw.
thumbsup.gif
 




frickea86

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i have a question...i've done all this and the wineing noise still hasn't gone away. my rough idle has some but it comes back off and on. i'm just wondering if its not functioning as well as it should be. how do u know when it needs replaced?...thanks...

adam
 




karl_burns

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I really think most IACs have to be replaced

The other day, while this thing was wining a whole lot during idle and driving, I decided to pull over, popped the hood, and yanked/removed the black plastic cap from the side of the IAC. NO more whining. NO loss in milage. NO change in idle.
Hmmmmm........
Karl
 




X~FACTOR

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karl_burns, wouldn't removing the black cap get the inside of it dirtier faster? It's gotta be there for a reason. If nothing else its there to cover the inside so dirt would not go in.
 




'96explorereddiebauer

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Originally posted by MaverickDaKid
Sorry I'm not that smart when it comes to mechanics but... what is that thing under the IAC called. It has 2 tubes leading down somewhere in the engine and has an electrical socket aswell?

That's the DPFE. I had to replace that last week because of the CEL.
 




nfixit

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Idle

Hello all, I just brought a 97' xlt 5.0L, and I notice an idle problem also BUT IT HAPPENS AFTER THE TRUCK WARMS UP!, when I sitting at a traffic light it starts to vibrate a little then some times alot(like it wants to shut off). My question is do the IAC sensor have problems on v8 also?. and is it located in the same place as the v6

Thanks in advance, the dealer I brought the truck is a distance (2.5hrs), I want to have an idea what the problem is so I don't have to make more than one trip!

Nfixit
 




V8BoatBuilder

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Just cleaned my IAC, it was SUPER dirty. I was having trouble starting, and a dip in RPMs (almost to the point of stalling) when coming to a stop. We'll see if the cleaning helps, I used denatured alcohol.

I wasn't able to clean the felt pads that well :(
 




Foo

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I also cleaned mine out today it was DIRTY! coming from a paintball backround which involves a lot of valving I don't even see how it sealed properly lol

I used some Turner Labratories electronic parts cleaner w/quick dry tech. and it worked great... just waiting for them to dry off ;)

Also do I need to take the negative battery cable off for about 10 minutes to clear the PCM?
 


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karl_burns

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Just let it dry and you should be fine

I don't think I disconnected my batter either.
Actually, my IAC continued to whine, and I yanked off the black cap. Instantly, no whine. So I'm thinking the cap gets loose and air tries to get through there causing the whine? I also think that becasue of the video someone put up here about the IAC whining when his hand attpeted to partially seal off that hole the black cap covers.
Thi is so weird.........
Karl
 




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