Ok - I am currently experiencing a surging idle from 1000 rpm to 1500 rpm. (for some reason - SEARCH isn't working for me)

First a little info of my ride = '94 Accord EX w/ a '94 JDM H22A (P13 ECU). I have had this swap for almost a year and now having an idle problem. During the winter, when the car was warming up, the idle would surge from 1500 rpm - 2000 rpm. Then would idle correctly (around 1000 rpm) when engine warmed up.

Now, the idle still surges when cold and now does it when the car is warmed up. Very frustrating to me - my car sound like a peice of crap and a stop light or in the parking lot. I am not throwing any CEL thus far and have shorted the ECU anyway just to make sure.

Talking with my neighbor (who is a certified mechanic - not specifically for Hondas though), we both think it is the Fast Thermo Valve or the Idle Air Control Valve.

Again, no check engine lights........

Any suggestions or feedback are welcomed.
Thanks

 

I had a 93 Prelude S and swapped in a 93 JDM H22a and i had some what the same problem. My car would surge from 1000-2000 rpm. When i started the car up it wouldn't do it until it warmed up......I found out what the problem was... a vaccum hose was off the backside of the intake manifold.

 

replace your fast idle valve, the piece bolted under the throttle body, where coolant hoses hook up. also, before doin just make sure you have no vac leaks. but if all vac is good, it is most likely the fast idle valve.