So something is screwed up with my idle.. It was trying to stall, so the tech sprayed the TB with some cleaner and the idle got stuck at 1500rpms.. Burning gas my brakes and just annoying so I took the IAC off and sprayed it clean, it dropped to 1100rpms but went right back to 1500..

I got a used IAC from the junkyard which supposedly was working but its worse...

So I want to just disconnect it and open the screw on the TB, its this fine or will it screw things up?

Maybe I just have bad luck but I find it odd that both IAC's are stuck at the same idle speed. The TB door is shut and nothing has move there, no vacuum leaks either and I dont feel like paying $200 for a new IAC right now.

 

if you mean the iacv i wouldnt disconnect it

 

Was the idle ever normal? What did you do to it after it started going haywire? What all did the technician do to fix the idle problem? Did you or the technician ever mess with the idle control screw?

No, you can not leave it unconnected. The idle control valve regulates the idle by adding or subtracting vacuum to account for things during normal operation. I'm pretty sure the car will be in a type of limp mode with no power with it disconnected, if not actual limp mode.

 

No one ever messed with the screw and its always been shut.. The idle always stayed at 750rpms for most of the time but then started dipping to like 150rpms for a few secs before bouncing back up.. Then it started stalling instead of just dipping.. So I told the tech, he just took off the intake hose and sprayed to TB.. Then boom stuck at 1500. I took off the IACV and sprayed it clean, put it back and then it sank to 1100rpms but later got stuck at 1500 again. I switched IACV's and its still stuck at 1500. Maybe they were both crap.. But what else could spraying the TB have done? The door is fine, is the IACV the only place the cleaner could have gone into?

 

Disconnecting the IAC valve and opening the idle adjustment screw will not put your car into limp mode. It will throw a CEL but it shouldn't limit your driving the car. In saying that, have you checked the IAC valve gasket? maybe it's leaking. Another thing to look at would be how the FIT valve is working?

If you remove the intake tube and temporarily cover the two air bypass holes inside the throttle body one at a time. What happens to your idle?



The FIT valve port is indicated by the red arrow. The IACV port is the top opening.

 

If the car is hot enough which means the iacv is hot enough and you spray carb cleaner into the area of the valve and it gets inside the iacv the carb cleaner will swell the seals inside the valve causing them to come apart and wrecking the valve. I did this myself one time not realizing it would happen. Make sure when you ever clean the iacv that it is at most barely warm if not cold.

 

I havent tried covering the holes.. I suppose if you cover the IACV it will just stall.. But i thought the FITV only worked until the car got hot? The temp isn't making a difference here.

 

Covering the IACV shouldn't cause it to stall. It should only drop to base idle if everything is working properly. Then if you have a vacuum leak or your FITV is wide open covering the IACV hole may not do anyhting. If the FITV is wide open, your right, temperature won't have any effect. IE the valve isn't closing when it should be. This is why you do the port plug test. You see what happens when you cover them and then trouble shoot from there.

 

Look at the idle adjustment screw. The passageway gets clogged up with gunk after a while, and when the idle drops too low some people back the screw out. Clean out the gunk and now it's open too far

Just solved this problem on my own car. After the engine rebuild and a brand new IACV it wouldn't idle below 1250 RPM, and would jump to 1500 after high vacuum driving. Acted just like a vacuum leak.

Turned out the screw was backed out all the way.

 

OK you guys say there are 2 HOLES, well I only have ONE lol

1998+ apparently had no FITV and it is built into the IACV, mine is a 2001 EX. here is a pic of my exact TB- https://honda-tech.com/forums/showthread.php?p=44423705 (One that says no FITV)

So.. my next step is to just get a new TB, I have tried to IACV's and both are the same. I covered the IACV hole and could here the air being sucked through the TB door. For some reason I guess its just not closing and the cable has slack.

Is it possible that the cleaner f*cked something up internally after going through the TB??

 

Ah yes the F23 has nether an IAC or a FIT valve, it has an RAC valve (rotary air control). When you said IAC I assumed that you owned a 90-97 F22 with an IAC & FIT valve. Sorry about that.

I can't see a cleaner doing anything other than removing oil/carbon build up. If it was throttle body/carb cleaner it shouldn't hurt brass or aluminum. Did you replace the o-ring type gasket for the RAC valve? Have you tried adjusting the idle adjustment screw on the top of the throttle body as mentioned above.

Warm the engine up to operating temps, shut if off and disconnect the RAC electrical connector. Start the car and adjust the idle adjustment screw (top of the throttle body) until your engine is @ 600 ±50 RPM. Turn off the car, connect the RAC and see if that does anything ..... that is, if you haven't already tried that.