hi everyone. I normally don't post on the prelude forums because i dont have one but my friends do. I already searched through past threads and couldn't find an answer to an idling problem that my friend has. My friend has a 1993 prelude that he just bought. It's in ok condition but he wants to fix it before he puts it on the road. The problem with the idle is that after it is warmed up the rpm bobs up and down. It shoots up to 2k and down to 500 nonstop. If anyone knows what the problem is it would be greatly appreciated. I read that it could be the pcv valve or idle arm thing but i'm the symptoms that the other people have are slightly different. Once again thanks alot, and i'm sure you prelude fans will be as helpful as the ones I talk to on the integra forums.

 

It is the very very very common idle surge, I've covered how to trouble shoot and hopefully fix it here:

https://www.honda-acura.net/forums/s...d.php?t=186819

 

im not sure bout yours but 91s have 2 idle speed sensors the problem is ussally 1 of those

 

ok so i just read through the thread. So by putting the aluminum sheet between the TB and FIV the FIV is blocked off and therefore no longer used right? I have just a few questions. First, how will not having a FIV affect the car? And what is an IICV?

 

FIV: The car will idle rougher in the cold, this can be adjust by the idle screw. If you do that, eliminate the coolant lines to and from the FIV. Your IAC (intake air charge will be a few degress cooler)

IACV? Idle Air Control Valve. Controls how the car idles by letting additional air into the IM rather than through the TB. Its not necessary either, you can block it off and remove coolant lines there as well, the car will idle rougher overall (flucuate a few 10's of rpms) but thats about it.

If you live somewhere freeeeezing cold for mutliple months in the year, just diassemble those pieces, screw the spring down on the wax plug and it'll be temporarily fixed.