james007

I have a 93 accord lx. I just cleaned the inside of my throttle body. I didn't remove it, i just took off the intake tube and cleaned the gunk from around the plate. My idling was fine before, but now it's bouncing all over the place.

Looking at this picture ...


... if i plug the upper hole on the inner left of the tb with my finger, my idle stabilizes. Where does that hole run to? The iacv? Not more than two months ago, I cleaned both my fitv, and my iacv. And everything was working properly before I cleaned the inside of my tb.

With the iacv plugged in, the idle bounces from 500-2000.

If i unplug my iacv, the idle bouncing still occurs, but only in the 1100-1300 range.

Adjusting the idle screw has no effect on the idle bounce or the range.

Also, the idle fluctuation only occurs while in park or neutral. Once in drive or reverse, it stabilizes, though it's bit high at 1100.

Any suggestions?

Coasterphreak

I have precisely the same problem on a 92 accord. I cleaned the IACV, FITV, and throttle body, and my idle is now really unstable. I've noticed it will stabilize until I put a load on the engine, at which point it will bounce wildly again.

philafelman

if you undid coolant lines, make sure your coolant is properly bled out to ensure no air is in there.

also, make sure your vacuum lines are ok.

to op....try putting a very small amount of rust penetrant to your iac.

jmjohnson128

your iac needs to be replaced, some cleaners have chemicals in them that DESTROY iac's. you can try to clean it but it won't fix it. it is no longer good..

james007

I did not remove any coolant lines and i have no vac leaks. My iacv was working just fine right before i cleaned my throttle body out. I have not touched the iacv since i cleaned it two months ago.

nus_dogg

It probably means that you need a new IACV; since, you've already cleaned both the IACV & FITV.

james007

While maybe not impossible, i find it extremely difficult to believe that my iacv decided to die at precisely the same time as when i cleaned out my tb.

My car was idling perfectly fine before, and the only change that has been made to my car is that the gunk was cleaned out from around the throttle plate. How can that cause my iacv to fail?

kitt

I never cleaned my IACV & FITV but I have cleaned my TB. When I cleaned my TB there was a period of time while the engine idle acted very erratic however after a while it stabilized. So maybe the computer needs time to reconfigure its settings. Try restarting your car by taking the negative side on your battery off for a bit. This should refresh all your settings.

Elvis1977

Replace your idle air control valve

HondaPartsHero

its possible you iacv sucked up that same gunk that was sprayed off your TB and has clogged it again

tpot90

Before replacing you iacv, reset the computer by (1) Unhooking your negative battery terminal for 1 minute or (2) Pull the radio/backup fuse & reinstall.

If this fails, x2 on the iacv.

james007

ECU reset accomplishes nothing. Also, I used to have an intermittent transmission problem too, at about 5-8 day intervals my trans computer would throw a code 7 for a shift control solenoid. I would simply reset the ecu and be good for another week. Now my car throws this code immediately upon engaging d4 every time i start, even right after a reset. This just began occurring right after i cleaned my tb. I tested my tps, and I'm getting .606 closed, and 4.3 wot. I know these values aren't perfect, but could the tps be responsible for my idle/transmission issues? I don't know what role the tps plays with the transmission, but it must be something since my tranny has some control over the throttle, via cable.

I'm going to try out a shift control solenoid out of a working vehicle to see if it really is the culprit with the transmission issue. But as for the iacv, I don't have access to another to test with. And before I go buying new parts, I'd like to know that the one I'm replacing really needs to go.

Is there a way to test an idle air control valve? I see it only has two electrical connections. So I'm guessing that the iacv is just a continuously variable solenoid. Is that right? If so, does anyone know what it's voltage range for engagement is? I'm hypothesizing that I can test it by hooking it up to 12v in series with a potentiometer (variable resistor), and checking it's response to being provided with 0v through 12v. Does this sound doable? My whole idea is based completely on my assumption of how the iacv works. If anyone knows for certain how the iacv works and accomplishes what it does, I'd appreciate some feedback.

mj213

Plug the upper hole and it stabilizes means it's your FITV not your IACV. Take the round flat plate off (two philips head screws) and then tighten that white "bowl" inside as tight as you can get it.

Hondas are notorious for this problem. Too bad it involves removing your TB again. If you haven't already, I would strongly suggest replacing the TB gasket.

james007

sorry, perhaps i should have been more clear. the tb in the pic is not from my car. i have a 93 lx and both the fitv and iacv are mounted on the front of my intake manifold.