IDLE HIGH THEN LOW CONTINUOUSLY

[sosaprelude93]

Hello fellow Prelude 4th Gen drivers.

Alright guys so i bought my lude about 6 months ago. The egine was completely damaged it had a blown head gasket and all out of timing.
I resurfaced the block replaced the gasket and had a valve job done on it. At first car was running ridiculously good no problems what so ever. after 3 months of continuous driving the car began to act up. Rpms would dropped completely and check engine light would turn on. I raised the Rpms check engine light went away and car ran good. afterwards the car began to idle wildly going from low to high continuously . Suspected that it was the coolant temp sense replaced it still didnt go away. Next checked the oxygen sensor and it seemed to be loose tighten it and the problem stopped. Now it does it occasionaly after driving hard what could this problem be?

[spiffyguido]

Fluctuating idles are often caused by the Fast Idle Valve (aka the Idle Air Control Valve). Have you replaced this one yet?

[sosaprelude93]

Hey spiff thanks for the help..
I read on another thread that there is a way to clean the IAC valve is this possible and if so would you reccomend this or is better just to replace the valve? And another question is the actual valve on the intake manifold?
Thanks
sosaprelude93

[spiffyguido]

The valve is mounted to the firewall side of the intake plenum, right next to the throttle body.

The step we usually suggest that people take first is to let the car cool down and then take the cap off the valve (two screws). Occasionally the plunger inside will have just come unthreaded from the shaft. Using a big flatheaded screwdriver the plunger can be rethreaded. This often corrects the problem. Otherwise, it may be necessary to get a replacement valve from an auto wrecker.

[RedRacer]

Yes, IAC is where to begin.

There are some good YouTube videos on how to do this. Not a hard thing to undertake, but it is in a semi-awkward place to get to easily. Back in the day the valve was on the front side of the throttle body, now it's down and back below the main throttle body intake port (butterfly valve)

This is a semi-good video to get the idea what you want to be doing. *Just mute the really crappy music and read and watch.

[sosaprelude93]

Thanks for the info can you post the link for the vid please redracer

O and I read all the stuff that happen with your lude and I have to say there is a god lol glad to hear you are bak on the road

[RedRacer]

Ah hell, I didn't include the link to the video~ DUH. Sorry.

Watch this video, just turn down the music, unless you like that music.....gives you the basic idea of where to locate the valve, how to remove it and how to adjust the wax pellet inside back to its seat....

http://youtu.be/s6wYeWQkya8

[RedRacer]

Thanks for the info can you post the link for the vid please redracer

O and I read all the stuff that happen with your lude and I have to say there is a god lol glad to hear you are bak on the road

Well, not quite on the road yet, but on the road to getting back on the road, is probably about right.

Thanks! I'll be glad too! I do miss driving Red!

[sosaprelude93]

Thanks spiff and red
I saw the video did and it was pretty simple definitely helped the plunger was way out went ahead and did the procedure and car idle is much better also switched out the can seals for the lude and oil leaks seem to stop but I cleaned the motor and I will see if the oil continues to leak thanks for help guys.... hopefully by the end of next month everything would be OK to start mounting performance parts

EAT SLEEP HONDA PRELUDE 93