Cleaning IACV, FITV and TB

[Twixle]

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.

This ad is not displayed to registered or logged-in members. Register your free account today and become a member on Honda-Tech!

[GhostAccord]

Originally Posted by TouringAccord

IACV = Intake Air Control Valve

FITV = Fast Idle Thermo Valve

TB = Throttle Body

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.


View of the Throttle body from the intake manifold's point of view.


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

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.



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

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

[AJ06]

Wait.... what?

[Shay91Racer]

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?

[TouringAccord]

Originally Posted by GhostAccord

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!

haha, oops. Thanks for correcting me

[TouringAccord]

Originally Posted by Shay91Racer

...could i jus use the carb cleaner...

yes, carb cleaner should be just fine.

[chibiko]

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?

[GhostAccord]

Originally Posted by chibiko

Do I need to drain the coolent first?

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.

Originally Posted by chibiko

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?

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.

[syler]

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

[syler]

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?

[JimBlake]

Originally Posted by syler

... 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?

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).


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.

[syler]

Thanks for the post Jim,

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" > 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." > 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...

[JimBlake]

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.

[syler]

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.

[GhostAccord]

Originally Posted by JimBlake

Or maybe CLEANER than the pics in GhostAccord's post.

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

Originally Posted by JimBlake

Find the idle air bypass screw about 11 oclock in this picture (thanks GhostAccord).

NP

[chibiko]

Thanks for the information. Things are exactly as you said. I have cleaned my IACV and FITV. It took my car several minutes to adjust to the change and after that it works great. A question is that when I wait for the temperature to increase to normal, I heard some clicking sound from the position of FITV or just around it. The sound is similar as that of the cylinder valves. After driving it for a short test, the clicking is gone. Don't know what the sound is and if it is normal. My car is old, maybe some electrical devices are bad. Here we know how to clean those valves, is there a way to check their functionality easily?

[JimBlake]

Originally Posted by GhostAccord

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!....

Yeah, I know those are before pictures, I was just teasing you for fun.

Another thing... I just answered a post about this for a newer Accord. Beginning about '96 or so there are no more FITV. (Anyone know what year?) On newer cars the function of the FITV is built into the IACV. Just in case someone with a 2001 Accord is all confused because they can't find their FITV.

Cheers.

[lowered94accord]

OK I have a quick question..I cleaned my FITV and IACV like 2 weeks ago and friday im gonna adjust the idle screw...can I reset my ecu just by pulling the radio back up fuse for a minute or so?..i think I read that somewhere before but I cant remember...thanks

[racerstodeath]

thanks

[JimBlake]

Originally Posted by lowered94accord

...can I reset my ecu just by pulling the radio back up fuse for a minute or so?...

I'm not real sure on a '94, but you're probably correct. Unless the ECU has it's own backup fuse & doesn't share the radio's.

Originally Posted by JimBlake

... 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.

[syler]

Originally Posted by chibiko

Thanks for the information. Things are exactly as you said. I have cleaned my IACV and FITV. It took my car several minutes to adjust to the change and after that it works great. A question is that when I wait for the temperature to increase to normal, I heard some clicking sound from the position of FITV or just around it. The sound is similar as that of the cylinder valves. After driving it for a short test, the clicking is gone. Don't know what the sound is and if it is normal. My car is old, maybe some electrical devices are bad. Here we know how to clean those valves, is there a way to check their functionality easily?

can someone answer this? im about to clean my fitv this friday

[GhostAccord]

There is a way to test your FIT Valve while you have it off your throttle body for cleaning.

When the FITV is at air temperature/cold it will allow air to pass throught. I clean mine off and just blow into the side with the spring visable and it should come out the opening with the cream/white seal, I always take the hands on approach....lol


Notice the position of the spring in the above image you can see a coil or two.

Now to perform the test all you need is a tap running hot water. With just enough water to pass through the FITV hold it under the hot water flow for at least 2-3 min.



After a few minutes you should notice that the spring will tighten as shown in the image below (if the FITV is working) To test simply try to pass air throught the openings again. If the seals are good and the FITV is working properly no air should pass through.



Note: This is a FIT Valve off of a D15b. Not all FITV will appear exactly as shown, but they will allow for the water to flow through in a similar matter.

[JimBlake]

How about a functional test installed in the car.

FITV's job is to provide a fast-idle when the engine's cold.
If the idle is high & slows down properly as it warms up, the FITV is doing it's job.
There should be no suction from the FITV port after it's warmed up.

IACV's job is to hold a steady idle when other stuff turns on & off.
After it's warmed up, the idle should be steady when you turn anything on & off.
- AC, headlights, wipers, defogger, seat heaters, whatever.

In other words, if you have a nice happy idle when you're done with all this stuff, then both IACV & FITV are OK.

[syler]

oh man, i just cant wait until tomorrow, im gonna clean the FITV, I still have a problem with my idle and my A/C. The problems is that im at a normal idle at 1k rpm, when i turn on my a/c, it is fine. But when I go to a stop, my rpm goes down as it wants to stall, then my A/C auto shuts off and im worried my a/c might break down due to constant shut off's.

[GhostAccord]

Originally Posted by JimBlake

There should be no suction from the FITV port after it's warmed up.

The FITV port is the bottom port in the Throttle body and the IACV port is the top port.

And don't be affraid to stick your thumb over it to check for vacuum, it's not like it's going to suck you into the motor or anything