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

[Cherokee kid]

Great thread!

It saved me some bucks. My 1995 Explorer would run but wouldn't idle. I remembered that it had this problem several years ago and the shop replaced something simple and easy to get to but i couldn't remember what. It was the IAC.

So, I pried off the black cap, unhooked the plug and took out the two 10mm bolts. Lots of black crud on the piston shaft and spring in the upper chamber.

I used some gun cleaning solvent called Remoil, q-tips and an artist's brush. The brush was great to clean the valve and the valve seat and the spring. Obviously, the valve and the valve seat have to be clean to seal properly and the return spring needs to be able to move. I soaked the black plastic cap in alcohol to clean the felt pad and blew a little solvent through the brass tube. Get all these clean and your good to go.

The Remoil not only acted as a solvent but provides a light lubrication as well. Put everything back on and it idles smoother than it has in a while.

 

[jjotero]

What a fantastic resource this forum is. I had some jerking issues with my 97 X so I got my lazy ass to Pep Boys and got a can of brake cleaner (no chlorine) and cleaned out the valve. Took off the black cap and clean the little pads as well. Started it up and had some idling issues and the moose call was evident. I figured the valve & pads hadn't dried completely and left it over night.

This morning, fired up the truck and smooth idling and no moose call. Next project is to clean the MAF sensor.

 

[tkye31]

Cross My Fingers!!!

Well Im going to try it! and see if it works I hope It does tired of the whinning myself! Well men wish me lots of luck Im not scared of getting my hands dirty or using a tool! I think I do very well for being a women!

 

[Didionkh]

I have a bit of a whine, mostly around "cruising" speeds, but nothing major. No idle issues to speak of. After reading some of the horror stories on here (and the triumphs) I almost don't want to crack open the IAC and just turn the stereo up. haha.

FYI, advanceautoparts.com has the IAC for $49.99.

Edit: $45.19

 

[bigjoej956]

Heres the problem Ive been having.

I noticed in the last week when my car is in drive at a red light and I have my defroster on full blast my RPMs will drop the car will shake a little and then the RPMs will go back up, then a little while later the same thing will happen the car has died once from this happening.
It does not do this when the car is moving or if its stoped and the heater is off or in park.
I did notice when driving with the defroster on full blast I had a smell like candles were just blown out.

I took out the IAC valve cleaned it let it dry but it back in but I am still having the same problems of rpms dropping. Should I just order a new valve? Is there any other thing I could try? Am I going to have to take it in to a shop? Could it be the air conditioning compressor?

 

[W3HOG]

Tools needed:
- 10 and 12 mm sockets
- 3 inch socket extension
- universal joint (swivel pivot socket thing)
- 12-inch ratchet (a short ratchet may not work – need something to apply a lot of torque to loosen the bolts)
- Phillip’s screwdriver
- rag
- throttle body cleaner

1. Unplug the 4 connectors from the IAC assembly. Undo the hose that connects the IAC to the
intake assembly.

2. The metal bracket holding up the gray-colored connector is blocking one of the IAC mounting
bolts. Using a 10mm socket, remove the bolt that holds the metal bracket. The bolt is just
below the purple connector – you have to twist your head and crane your neck around to see
the bolt.

3. Remove the 3 mounting bolts using the 12mm socket. The lowest bolt may require the Universal joint.

4. Pull out your IAC valve and clean it w/throttle body cleaner, rag, and old toothbrush.

You may even want to separate the plastic valve to clean it more thoroughly. Use a philip’s head
screwdriver, but make sure it is a snug fight. It’s on there tight and if you don’t have a good
fitting screwdriver, you could ruin the screw head.

Re installation is just the reverse of these steps. It may be easier access to the IAC if you remove
the whole air intake assembly, but it’s not necessary.

What year vehicle are you referring to? Mine is simply under the black top cover and on the top of the intake, (2) 8mm bolts, easily reached.
2001 Explorer Sport Trac

DAN

 

[GregAW]

What year vehicle are you referring to? Mine is simply under the black top cover and on the top of the intake, (2) 8mm bolts, easily reached.
2001 Explorer Sport Trac

DAN

Mine too Dan and I have a 2000 Explorer Limited. I was surprised at how east it was to get to. How did you clean yours and did you spray any WD-40 or something like that to lube it? Greg

 

[W3HOG]

No Wd40, that will leave a residue, you want something that evaporates quickly like CRC Electronic cleaner, or some king of Throttle body cleaner.

I'll be putting mine back on in a few minutes, hopefully it works, otherwisa its off to Advanced auto to simply buy a new one!!!

Good Luck, This forum is awesome isn't it!!!!

DAN

 

[Corik]

Heres the problem Ive been having.

I noticed in the last week when my car is in drive at a red light and I have my defroster on full blast my RPMs will drop the car will shake a little and then the RPMs will go back up, then a little while later the same thing will happen the car has died once from this happening.
It does not do this when the car is moving or if its stoped and the heater is off or in park.
I did notice when driving with the defroster on full blast I had a smell like candles were just blown out.

I took out the IAC valve cleaned it let it dry but it back in but I am still having the same problems of rpms dropping. Should I just order a new valve? Is there any other thing I could try? Am I going to have to take it in to a shop? Could it be the air conditioning compressor?

You are low on feon, or whatever else you use for your A/C
Mine does it too, I have a small leak on one of my hoses so the compressor turns on and off a lot. You should be able to hear it turn on and off. At least in my '91 Ex I can while driving.

 

[barbaroja]

Well I just wanted to point out that I cleaned my IAC cause was having the rough idle thing. Cleaned it many times with electrical contact cleaner, however, there is no sensor on the IAC, as the OP says. In fact after cleaning, some oil in the shaft and the spring worked wonders. Still have a little stall after you push the accel hard and let it go abruptly. I will change the IAC gasket.
Some members say there is no gasket there, I can confirm there is one, but it seems to have lost its sealing abilities over time. I read a report of someone having luck with the IAC only after installing a new gasket.

 

[barbaroja]

Also, searching for the rough idle issue, I also noticed the truck having good power until I hit 3500 RPM. So I checked the DPFE sensor, and one of the hoses was like thin and bent. So I tried to take it out of the sensor to cut the bad spot wich was just right next to the sensor and BAM! The little pipes that go into the sensor just broke as it was a cookie. So it looks like the sensor element itself was fine, but the case cristalyzed with heat. That for me is bad quality, bad choice for plastic. The new sensor I got is a F77Z part, original part was a F77E part.

I wonder if the Z letter being afterwards the E letter in our alphabet means its a revised piece???

Also had to get new hoses. Hope it goes well after these changes.

 

[W3HOG]

Can you give a little more description on what the DPFE sensor is and where it is located, so I can give mine a look please.

thanx Dan

PS< cleaning my IAC has done nothing for me, so I guess it is time to buy a new one.

 

[MIKE161]

THanks Mr. burns!!! you helped me out a bundle.

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:

Two 10mm bolts to remove, and unclip the electricals:

Here's the dirty intake's connection with the IAC:

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):

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

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?

 

[tcruise709]

An idle air control actuator or idle air control valve (IAC actuator/valve) is a device commonly used in fuel-injected vehicles to control the engine's idling RPM. In carburetted vehicles a similar device known as an idle speed control actuator is used.

 

[hasoan]

Thank you Wikipedia

 

[krisjenner640]

The idle air control valve (IAC) is a small component that controls air coming into the throttle body of your car. Normally, the air intake is controlled by the throttle plate, which is in turn controlled by the accelerator pedal.

When you pull up to a stop and idle, however, the throttle plate is closed. The IAC valve then opens to a certain point, allowing in a carefully calculated amount of air to allow the engine to idle properly. If this valve gets gunked up with carbon debris, which happens over time especially on higher mileage vehicles, the valve will either not open or it won't open properly.

The result? Either a rough idle or, in my case, a complete stall. The valve wasn't opening sometimes, completely cutting off the air to the engine and forcing it to stall.

On the 1997 Chevrolet Cavalier, this is on the back of throttle body. Stand in front of you car, and look under the hood. You should see a large air hose that connects to the air filter at one end (located in the front right) and to a big metal thing on the other end (in the center of the engine compartment, all the way in the back). That metal thing is the throttle body.

Remove that large air intake hose. There should be two screws holding down clamps. Remove those, and the hose will come off no problem. Be careful, though, it will be dirty.

This will reveal the throttle plate and the front of the throttle. You should see a large metal plate covering a large hole, and above that a much tinier hole. That tiny hole is part of the Idle Air Control Valve.

On the back of the throttle body, you'll see a small component that is attached by two screws. It has a wiring harness plugged into it. This is the IAC valve. You need to take it out.

Unfortunately, it's in a crappy place to get to. You need a hex key or hex bit for the screw. If you have a small hex key, you should be able to reach in and unscrew the screws. I was able to go to Lowes and get a t-shaped screwdriver. It worked kind of like a ratchet, but it took a hex bit instead of a regular socket. Without it, I don't know how I would have gotten in their and removed the IAC.

 

[GRNMACHINE]

WoW 12 pages. Has anyone commented on long term results with non Ford IAC? Prices can be as low as $25 on ebay. CHeapest I can find online is $96 for the Motorcraft IAC I need. I generally dont buy generic parts, but considering the cost difference and ease to replace I may have to rethink it... Also didnt find a part no. for gasket. (Cleaning and soaking IAC overnite did not fix the foghorn noise). As others have pointed out, removing the black cap silences the noise totally, but mpg went down to about 12...

 

[tchalm]

Great forum! After reading just a few of the pages of this thread I cleaned out the IAC on my 98 SOHC and that solved the problem I was having with rough idle and dying when cold.

I was surprised that when I removed the IAC there was no gasket. So I put it back together like I found it and it runs fine. IDK.

Thanks!

 

[GRNMACHINE]

x2 on great forum and INFO!! Small Update, ended up soaking the cap for hours in alcohol. So Far, idle seems better and no noise...

 

[bauers]

Brilliant

Just encountered the idle problem today, and wanted to say that tkz to this post on the first Page, I was able to clean the iac and started the EXACT without a problem. Tks again. It's a 15 minute job minus the hour for drying (took the dog for a walk lol).