having an idle issue.on start up my car idles at 3,000 and as it warms up it bounces between 1,000 and 2,500 constantly. already cleaned my IACV and FITV and they are both in good working condition. any suggestions??

 

Any CEL codes?

After the engine has fully warmed up and has the high fluctuating idle problem, use your finger to cover the port inside the throttle body leading to the FITV. Do you feel any suction? Does this prevent the idle problem?

If not, do the same test on the port leading to the IACV.

 

no cel! alright thanks ill give that a shot tomorrow

 

Intake Mani gaskets are bad. Spray some TB cleaner on it see if idle changes.

 

well its not a faulty intake manifold gasket

 

Huge Vac leak maybe?

 

i adjusted the fast idle it was way out. there is a screw on the throttle body,is that an idle air adjustment?

 

Yes tighten it a bit with the car on and get it right

 

I'm guessing this is a c1?

 

if your talking motor its a jdm b16a sec gen

 

Had the same issue, turns out it was the white plate that holds the spring down on the FITV, came loose so I screwed it back in and it was golden.

 

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/

 

yea no antifreeze is a big deal haha

 

i noticed in that thread it said use carb cleaner to clean it. research the diff between carb cleaner and throttle body cleaner. they are very similar but there is an extra chemical in carb cleaner that may destroy the finish on your throttle body

 

haha jk man dont mean to thread bash alot of hondas have that problem. i had that problem to id spray some blaster on it. if that dont work a buddy of mines was jumping from 2000 to 3000 and i checked for vaccum leaks put a hose on it. and moved the dizzy back a little bit. fixed it real quick

 

There can only be a certain amount of things it is, but when an idle is that high usually is a vacuum leak due to pulling in a lot of extra air rather than a small vacuum leak (dont quote me). You can use unlit propane too, this always works better and as you know gas is much more speratic and should help find the leak. The extra octane from the propane will raise the idle, or sometimes bog.

If you unplug the IACV what does it do?

 

im just glad my idle is fixed! that was starting to drive me insane lol someone always bashes my threads on here im used to it lol

 

i hate when people bash threads lol. what did you idle problem end up being?

 

my fast idle thermo valve needed to be adjusted, it had walked itself out. now it purs like a kitten lol