cs_729

Hey guys just got my new 1992 prelude with a jdm h22a swap. I have noticed that the idling bounces up and down. I fiqured that it could be the IAC valve, which I found out was correct. I went to my mechanics and he said that becuase they reused the h23 intake manifold and IAC valve, its causing the bouncing idle. He said in order to fix it i need the H22a IAC valve. But my question is this, will the h22a IAC valve bolt straight onto the h23a intake manifold??? If it does thats an easy fix, if not i would have to get a new intake manifold for it to bolt on. And second question would be if i need a new intake manifold, should i get a Skunk2 manifold or just the regular OEM manifold?? Is the Skunk manifold a bolt-on or will the ecu need to be reprogrammed for the new manifold. Any help would be awsome, thanks

IAC= Idle Air Control Valve

asheylarry

i know this is long, but it will help you.

idle speed is controlled by 2 things: eacv and fast idle valve. eacv varies amount of air that bypasses throttle plate in response to signals from ecu. after engine starts eacv opens for a short time to increase idle speed. activation time is dependent on coolant temperature. when temp is low eacv is held open to maintane faster idle speed. when engine is warmed up it is activated only to maintane minimun idle speed.
The fast idle valve allows additional air to bypass the throttle plate into the manifold. increased idle speed is prevents engine from running erratically during warmup. fast idle valve is controlled by a thermo wax plunger which contracts when cold and expands when hot.
here are a couple things to check out--- a low coolant level will not activate the fast idle valve, which in turn will give you irradic idle. another thing that happens quite commonly on prelude and accord is that the thermo wax plunger sticks in the top of the valve and keeps allowing extra air to bypass the throttle into the manifold, so the computer sees the extra air (sees it as high idle) and it trys to adjust the idle down, then the idle gets to low and it tries to bring it back up, but with the extra air, idle is too high, so it trys to bring it back down again, and it repeats indefinately.
so check coolant level and check fast idle valve.

t3t4delsol

you can bypass the coolant line in the mani by rerouting it back to back to it self and then just put a line to connect the old coolant opening to each other, you will pick out a horsepower or two by doing this because you will not have an issuse with the heat in your intake mani