Cleaning IACV, FITV and TB
 

I was having some issues with my car Idling at random spots when In neutral. When I would push in the clutch or throw it in neutral it would drop to 1000 rpms, and sometimes bounce back up to 1200-1500 and stay there, and other times it would drop back to 750 where it should be. I also had a pretty consistant miss at idle that I thought was unrelated, but cleaning the two valves solved that too.
The whole process took me about an hour and I'm more than pleased with the results.

First thing is to get a mocha from the cute coffee girl down the road. Take off your intake, and strut bar if you have one. Those will just get in your way and make the job harder. Be careful of the cruse control cable while you are working in that area, you don't want to kink it or bend it.

https://farm1.static.flickr.com/124/...e5500645_o.jpg

With those out of the way you can easily access the three 10mm bolts holding the fitv on.

https://farm1.static.flickr.com/143/...ab7988de_o.jpg

Go ahead and pull it down, no need to remove the hose. There are three little rubber o-rings, you can see in my pic that one was left stuck to the bottom of the t/b, make sure they are all seated properly before re-installing.

On the end of the fitv there is a brass plate with two 8mm bolts holding it on. remove that plate.

https://farm1.static.flickr.com/164/...00cb5804_o.jpg

underneath that plate is the white valve body that comes loose and causes the vacuum leak that causes your idle to hunt.

https://farm1.static.flickr.com/160/...a43ee9dc_o.jpg

You can see in the pic that on both sides there is a little notch for a screwdriver for tightening it up. I just used a small flathead to spin it. Mine spun about one and a half rotations before it was nice and tight. Thats it here, nothing to clean. re-install the plate, wrap it in a small towel to keep it clean, and set it aside for now.

Next is the IAVC. With everything removed so far its pretty simple to get off. First unclip the harness. Then on the back side of it there is two 12mm bolts. The longer one is on the bottom. Remove the bolts first, then remove the two coolant hoses. I was able to pinch the clips and slide them down with my fingertips, but a pair of needle nose pliers might be needed for some. The hoses came off easily.
In the pic you can see all the crap clogging the screen, and the body filled with black buildup. Thats what you need to clean.

https://farm1.static.flickr.com/146/...eea95d5b_o.jpg

With it completely removed from the car, remove the rubber gasket so it doesn't swell from the cleaner. Fill it up with carb cleaner and let it sit for a minute. spray it out and repeat a few times. When mine was done the screen looked shiny new and the valve inside was white and clean as snow.

https://farm1.static.flickr.com/160/...f0f55fae_o.jpg

Now while you wait for it to dry grab an old toothbrush and your carb cleaner and clean your throttle body. Hold the butterfly open, spray it all down and scrub both sides with the toothbrush. clean the whole thing out well using copious amounts of carb cleaner to break up the deposits and rinse them out. There are two little holes that lead off to the IAVC and the FITV, spray those clean also.

https://farm1.static.flickr.com/154/...03aded66_o.jpg

Now re-install everything, reset you ecu so it can learn any changes you've made by cleaning up the idle, and enjoy how smooth your machine runs.

https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

cool, so does this fix our "bouncing 1000-1500rpm repeat" idle when we warm up our car?

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

yeah, crank that FITV all the way down; kiss the warm up fast idle goodbye.

Re: Cleaning IACV, FITV and TB (hondadude)
 

No sarcasm here or anything but can you explain honda dude?
what can screwing to far do? Cause I might perform a little maintainance by cleaning the IACV and FITV.
I don't know about the IACV though cause I'm having a bitching time getting the coolant hoses off in that cramped space.

Re: Cleaning IACV, FITV and TB (Homesickelian)
 

This is how the FITV works..."At room temperature, the wax in the enclosure is small enough so that the needle is pressed in by the spring loaded valve, thus letting in air through the ring-cap and increasing the idle. The needle sticks out 6mm. As the temperature of the coolant rises to about 150F, the wax expands and the needle eventually protrudes to about 11mm at around 220F. The force of the needle on the spring keeps the valve closed. If the ring-cap is loose, there is not enough force to keep the valve closed thus letting in air and raising the idle when not necessary."

Makes sense then that if you "crank that FITV all the way down;" Like hondadude says that it wont work anymore. I'm just saying to tighten it up till its not loose, witch will stop the vacuum leak causing the idle problems.
I respect your knowledge hondadude, But I've read many tech articles explaining this fix, and not one saying that they lost their fast idle at startup.

https://honda-tech.com/zerosearch

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

I should add that My car warms up now around ~1600 rpm's.
The same as it always has.

I dont think your suppose to put carb cleaner inside the IAC, theres seals inside that could get damaged.

Wrong^^ Cleaning it with carb cleaner is one of the only ways to clean it. It has worked countless times with positive results for the owner.

Re: (rollercosta123)
 

Why did you do this?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rollercosta123 &raquo;</TD></TR><TR><TD CLASS="quote">subscribed</TD></TR></TABLE>

You can just click on Subscribe at the top right of the page and select to either Watch or Receive Email Notifications. You don't need to bump a thread to just subscribe to it.

Re: (TouringAccord)
 

sorry. No reason to start complaining

Re: (rollercosta123)
 

I'm not complaining, I'm informing.

Re: (TouringAccord)
 

Finally!! It worked!!! Thanks!!!

im gonna have to do this

need to know the abbraviations...

IACV?? FITV?? TB??

Re: (EvenStar)
 

IACV = Idle Air Control Valve

FITV = Fast Idle Thermo Valve

TB = Throttle Body

edit:
correct the IACV, thanks GhostAccord for catching that https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

I did just what you said to do. The problem went away. no more pulsating idle. The car runs real smooth, it's wierd adjusting to it. The only thing that i noticed is a random humming that comes on and off. it sounds like it's coming from the brake master cylinder area, but haven't check yet. Thanks hondadude, great directions and advice.

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

sticky. .
nice write up https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Cleaning IACV, FITV and TB (abxman)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abxman &raquo;</TD></TR><TR><TD CLASS="quote">I did just what you said to do. The problem went away. no more pulsating idle. The car runs real smooth, it's wierd adjusting to it. The only thing that i noticed is a random humming that comes on and off. it sounds like it's coming from the brake master cylinder area, but haven't check yet. Thanks hondadude, great directions and advice.</TD></TR></TABLE>

this write up is GREAT....i did this step by step on my 92 4dr dx and it worked like a charm....but i did not reset my ecu....any help on resetting it?

Re: Cleaning IACV, FITV and TB (Grandhustleman86)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grandhustleman86 &raquo;</TD></TR><TR><TD CLASS="quote">....any help on resetting it?</TD></TR></TABLE>Disconnect your battery for a couple minutes. But first, find your radio anti-theft code...

Then, start the engine without touching the gas pedal. Let it idle to warm up completely without touching the gas pedal. After the radiator fan comes on, you're done.

Re: Cleaning IACV, FITV and TB (JimBlake)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Disconnect your battery for a couple minutes. But first, find your radio anti-theft code...</TD></TR></TABLE>

couldn't you just pull the ecu fuse? that way you don't have to worry about the radio.

Re: Cleaning IACV, FITV and TB (TouringAccord)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TouringAccord &raquo;</TD></TR><TR><TD CLASS="quote">
couldn't you just pull the ecu fuse? that way you don't have to worry about the radio.</TD></TR></TABLE>
Yes.

But we've got a bunch of people in this thread, different year cars, etc. The ECU fuse isn't always the same fuse # in the same fuse box, and it doesn't always maintain the stereo security.

For '98-02 Accords, pull fuse #13 in the fusebox in the right end of the dashboard (near the door hinges).

i love you you save me a lot of money

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

Im gonna try this for surezzzz!!!

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

wow this interesting... just bought my carb cleaner....

*I WILL POST FOR THE NONBELIEVERS* lol

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

hey but i have a question.... i was screwing the notch, as u mentioned, it turned about 4 times before being tight. However the question is this... when i took the brass plate of my FITV it was pretty much dirty inside it. what can i use to clean it?

Re: Cleaning IACV, FITV and TB (Shay91Racer)
 

I'd use a toothbrush and some starting fluid, then dry it out with a rag.

OP, thanks for the great write-up, did this and wah-lah my idle was fixed. https://honda-tech.com/forums/images/smilies/emthup.gif

Re: (TouringAccord)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TouringAccord &raquo;</TD></TR><TR><TD CLASS="quote">IACV = Intake Air Control Valve

FITV = Fast Idle Thermo Valve

TB = Throttle Body</TD></TR></TABLE>

Not that I'm perfect buy any streatch of the imagination or anything but the
IAC valve or IACV = Idle Air Control Valve

Not meaning to be nit picky TA....sorry!

One more point to this regular maintenance tip for cleaning the FITV, IACV, and TB. If you find that you are doing this more frequently than you think you should be and it finally doesn't work, 9 times out of 10 it is actually the Throttle body ports that are clogged with carbon or oil from the intake manifold side. I wish I had pics of the last TB I cleaned it was gummed up really bad so bad neither the IAC valve or the FIT valve were working. So if this happens to anyone here there is one more step that you can add to the end of the above proceedure and that is to remove your TB and give it a good soaking in TB cleaner/Carb cleaner it's only another 4 nuts and it's off, just make sure to have a replacement TB gasket before you do this, or have a roll of Felpro Karropak .035 on hand to make your own as I do.

Just a few pics to show what I am talking about....everyone loves images

4 easy nuts to remove if the studs come out with the nuts no big deal they'll go back on the same way.
https://i133.photobucket.com/albums/...leaning-01.jpg

View of the Throttle body from the intake manifold's point of view.
https://i133.photobucket.com/albums/...g-air-flow.jpg

wow colour coded....("colour" yes I'm Canadian...lol)
Red arrows = Air Flow
Blue Circle = IACS, Idle Air Control Screw
Yellow Circle = IACV air ducts/ports/holes......whatever you want to call them!
Green Circles = FITV air ducts/ports/holes...etc!

The area around the (Blue)Idle Air Control Screw, this is fed directly from IACV port in the throttle body, it does not go threw the IAC Valve. This is were the majority of the carbon and oil ends up gathering Remove the IAC Screw and clean this out with a pipe cleaner https://honda-tech.com/forums/images/smilies/emthup.gif

The following image shows (top yellow circle)where the air comes in threw the throttle body into the manifold and on threw to the IACV. The lower yellow circle shows where the air is finaly passed into the manifold from the IACV.

https://i133.photobucket.com/albums/...flow-chart.jpg

Nice and clean looking eh?....NOT! This is where major improvements can be made in the general performance of an older vehicle. every little thing counts.

Hope this helps!

Cheers https://honda-tech.com/forums/images/smilies/emwink.gif

NOTE: [i]To avaoid any confusion I must state that the Throttle Body & Intake Manifold in my images above have not been cleaned. Do not base how clean they should be on these images, they are only for visual reference of parts to be cleaned.[i]


Modified by GhostAccord at 6:50 AM 4/17/2007

Wait.... what?

Re: Cleaning IACV, FITV and TB (accord2021)
 

a toothbrush and starter fluid huh? alrighty then... i'll give it a go. does it have to be starter fluid or could i jus use the carb cleaner since i have it lying around the house? http://images.honda-tech.com/set1//smile/emcrook.gif

Re: (GhostAccord)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GhostAccord &raquo;</TD></TR><TR><TD CLASS="quote">Not that I'm perfect buy any streatch of the imagination or anything but the
IAC valve or IACV = Idle Air Control Valve

Not meaning to be nit picky TA....sorry!</TD></TR></TABLE>

haha, oops. Thanks for correcting me https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Cleaning IACV, FITV and TB (Shay91Racer)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shay91Racer &raquo;</TD></TR><TR><TD CLASS="quote">...could i jus use the carb cleaner...</TD></TR></TABLE>

yes, carb cleaner should be just fine.

Re: Cleaning IACV, FITV and TB (mtnwkr)
 

Do I need to drain the coolent first? Another question is the IACV is behind my intake manifold, so the space to loose it is really tight and I cannot put a socket wrentch there. How do you guys do?

Re: Cleaning IACV, FITV and TB (chibiko)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chibiko &raquo;</TD></TR><TR><TD CLASS="quote">Do I need to drain the coolent first?</TD></TR></TABLE>

No You do not need to drain the coolant, just make sure that you have a rag or a drip pan under your car as there is a bit of coolant in the lines.... maybe 100ml that's about it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by "chibiko" &raquo;</TD></TR><TR><TD CLASS="quote"> Another question is the IACV is behind my intake manifold, so the space to loose it is really tight and I cannot put a socket wrentch there. How do you guys do?</TD></TR></TABLE>

I have the same problem with my 96 Accord, I use a wrench to crack both of the bolts then after that you can usually turn them by hand.

nice writeup, I think im gonna do this on my day off...

hi peeps, i just cleaned my IACV this morning, it was so easy as 123, but I havent got time for the FITV, maybe on friday. I have a question though, will cleaning the FITV or the IACV fix my rev problem? it goes a little like this:

even though the engine is already on the operating temp, whenever I rev, and let go, rpm goes down as if the engine will want to stall, but its catching its breath, what can be the cause of this?

Re: (syler)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by syler &raquo;</TD></TR><TR><TD CLASS="quote">... whenever I rev, and let go, rpm goes down as if the engine will want to stall, but its catching its breath, what can be the cause of this?</TD></TR></TABLE>That might be your base idle is off. So I'll add to this cool thread since that's sorta related...

First, check for vacuum leaks and get rid of any air in your cooling system. Clean your TB like those pictures above. Or maybe CLEANER than the pics in GhostAccord's post.

The throttle cable should have a little slack, and the mechanical stop for the throttle must not hold it open. Only just barely enough to prevent it from wedging stuck closed.

Then you can set your base idle. That's not the operating idle, but the base idle is a LOW idle speed you set with the IACV unplugged. Look up the "BASE" idle speed for your year/model. It's usually around 500 or 600, and it's NOT the rpm listed on the sticker under the hood (that's the operating idle).

Find the idle air bypass screw about 11 oclock in this picture (thanks GhostAccord).
https://i133.photobucket.com/albums/...leaning-01.jpg

1 - Warm up the engine, turn off all electrical loads.

2 - Jumper the SCS connector (prevent ECU from messing with spark timing).

3 - Unplug the IACV - idle rpm will drop - try to keep it running.

4 - Adjust idle with idle air bypass screw to set your base idle rpm.

5 - Shut off, plug IACV back in, cool down, RESET ECU.

6 - Start engine without touching gas pedal.

7 - Let it idle to warm up without touching gas pedal. This allows the ECU to learn the behaviour of the idle system after it's all cleaned & adjusted.

Re: (JimBlake)
 

Thanks for the post Jim, https://honda-tech.com/forums/images/smilies/emwink.gif

have a few question though if you have time.

I am not sure of the "Base idle" of my d16z6 engine, i dont have the manual anymore,. hope someone can answer that?

"2 - Jumper the SCS connector" &gt; sorry but what is scs? is it the airbag? my car does not have one. :D so i gez i have to bypass that.

"3 - Unplug the IACV - idle rpm will drop - try to keep it running." &gt; do you mean while the engine is running, il unplug or remove the IACV? and adjust the base idle?

again, thanks for helping me man... its great to be here...


https://honda-tech.com/forums/images/smilies/emthup.gif

Re: (syler)
 

I Don't know your base idle...

The service check system (SCS) connector is the same plug that you jumper when you're reading ECU error codes. Blue plastic plug, 2 wires. I think in a Civic (D16?) it's tucked up between the glovebox & the right kick panel.

When you unplug the electical connector from the IACV, the idle speed will drop. Maybe it'll want to die, so you may need to baby it with the throttle to keep it running. Use the idle air screw so it runs when you let go of the throttle. Then carefully adjust it back down to base rpm.

Part of the problem is when there's idle problems, it's tempting to simply go for the idle air adjust screw, without going thru the proper procedure. If the original problem was a dirty IACV, and someone tried to 'fix' it by just turning the idle screw, or tightening the throttle cable; then it gets all messed up.

Thanks again Jim, yes, now I know what the scs mean,and I found it.

I will do the procedure you mentioned and keep this thread up until I get my problem solved. I did not reset my ECU this morning that is why maybe its still messed up.

Re: (JimBlake)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">Or maybe CLEANER than the pics in GhostAccord's post.</TD></TR></TABLE> Yeah this is one that I just took apart, I'll post up some before and after shots when I get this one cleaned up right!.... I have made note of this fact on my images. Thanks Jim https://honda-tech.com/forums/images/smilies/emthup.gif


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by "JimBlake" &raquo;</TD></TR><TR><TD CLASS="quote">
Find the idle air bypass screw about 11 oclock in this picture (thanks GhostAccord).
</TD></TR></TABLE>
NP https://honda-tech.com/forums/images/smilies/emthup.gif