Im running a b18c1 block with ctr pistons mated to a b16 head with ITR manifold and itr throttle body. Ever since i got it back the IACV has been screwed up. The problem is ive tried 3 different working IACV off my friends cars and the problem still persists. Idles at 1.6k and when i drive and let off the gas at low rpms, the rpms rise by themselves to about 4k. Now your all saying vacuum leak.....wrong. I have a new tb gasket and intake manifold gasket, torqued down to factory specs. I sprayed carb cleaner over all the vacuum lines throttle body, intake manifold you name it i sprayed it. When I remove the harness from the IACV the cars idle drops to about 800 rpms. What is the harm if the IACV is not hooked up, also and what is the voltage supposed to be to the IACV. I get no check engine light when its plugged in and idling really high.

 

so wait when you unplug it from the ecu it idels down. if you dont have it hooked up you will have another vacume leak. what you can try is putting the lines going into the iacv together and capping the iacv. but thats only temperary.

 

there are only two coolant lines that go to the IACV. There are no vacuum leaks. Would a faulty TPS sensor also give a problem like this. Also having the IACV not hooked up, will that cause any power loss?

 

Although my motor is completely stock... I have that same problem recently. I have a d16y8... 00 civic ex coupe. I've noticed of recently... when I start up my car drive it around it's fine... idles a little low though (maybe like 500rpm). But then SOMETIMES (not always) if I drive it hard when I'm cruising and put it in neutral or I'm coming to a stop and let off the gas and with my foot on the clutch... my idle jumps up to 2000 rpm and stays there till i come to a complete stop... and only a complete stop... if i keep rolling off momentum it will stay idling at 2000rpm. Then sometimes when i drops... it drops to like 0rpm... literally... where the car almost stalls out on its own. I've been trying to figure out what the hell it could be but i have no clue. My only mods are an Injen intake, a B&M FPR, and some Bosch platinum plugs... all of which i've had way before this problem started. In addition to those mods I've ran a 55 shot of nitrous on the motor for a couple months last year. I've tried toying with the fuel pressure to see if maybe it was too high or something but that doesn't help. That's the only thing I've tried to solve the problem. I took my car to the dealership for a 30k mile servicing after the idle was acting up and that didn't even fix it. Anyone have an idea what the problem could be?

 

hmm mine does the same damn thing. Maybe it could be a problem or leak in the hydrolic clutch system? Can anyone elaborate on this?

 

If it were a leak in the hydro system... would it actually leak out of the car... say onto a driveway where it was parked? cause my pops has been telling me something's leaking from my car but i checked the oil and it was fine.

 

back from the dead! I have this same problem...help anyone?

 

IACV should read about 20 Ohms across the pins you can also check continuity between each pin and the ground or case of the IACV. Anything higher replace the IACV. If its shorted you will see that its not open. (Thats for furture reference if anyone searches the Forums)

Bad PCV valve between the intake manifold to the factory crank case catch can? Try pulling off the big hose going through the intake manifold and plug the top where the hose is supposed to go, if the issue disappears the PCV valve is bad or cracked causing an air leak. Could just be gunked up. Are you venting the valve cover to atmosphere by chance? If so you are pulling vacuum through the motor to atmosphere. AKA air leak

 

everytime im having idle issues and narrow it down to the IACV, i clean the **** out of it with carb cleaner and try again. after usually two attempts it always settles down. Last time i checked they go for around $250 so its definitely worth a few minutes and a can of carb cleaner.

 

check your throttle stop i know it seems idiotic but sometimes it is that simple.

 

I have a h22 and when i bought the car it had the idle surge problem.. Ended up being the ecu.. I beleive the iacv code is either bad ecu or iacv.. I know its a old thread but it might help someone..

 

how to check iacv
warm car fully
unplug iacv. if car doesnt idle perfect try to adjust with screw while the cel jumper is connected(2 pin connector by ecu)
if the idle does not correct than your iacv is messed up or wired incorrectly.
if it idles crazy high it could be your throttle plate needs adjusting or is sticky. vaccum leak. or timing

 

Holy crap this thread was taken out of its grave from 02 to 09 then now to 2011. Damn thats like a 9 year dig!!! LOL - its helpful though - thats what matters

 

It's better then the guys making a new post and having someone send him a link to this page lol:h ugs: