i have a 92 prelude and my car idles up and down real bad. Now their ia a line connected to the map sensor that when i un hook it the problems stops but i begin to get black smoke out of my exhaust i have already replaced the map sensor and that wasnt the problem. So if anyone has any ideas on what it could be please let me know.

chris

 

i tried a lot of stuff on my 92 until i finally took it to a shop and it cost $81.94 to fix. tha's with parts and labor. the problem was i needed to replace my hot wax valve. apparently some part inside it came off. how this helps

good luck

 

Hey man what is a hot wax valve? I called every shop around here and no one has heard of it? If you could find out for me that would be a big help im to the point where i have no idea what my problem is.

thanks
Chris

 

does it idles up and down about 500 rpms ish ? at neutral ?

if so, replaces your fast idle valve under the TB

stan

 

ok man... Its either one of two things.. Now you have to be more specific and tell us exactly what its doing.... Its either jumping form 1-3 while wraming up and then 1-2 warm(estimated!, something like that Its just really bouncing and surging!), or its just idling rough and uncertain... If its jumpy than you need a new fast idle thermostat valve! Its a 70 US part you cna only get from honda... Its a ez install... Do a search and you will find info and even a how to about it probably... If not, Ill right one.. I replaced mien last week after it seized up on me for the 3rd time.. I got tired of it and just abought a new one... Otherwise search for hot wx valve..... One guy did a writeup on how to adjust it and fix your hassle.. Everythign should eb possible to find and other guys will give u links if you cnat find it... I know both topcis are covered often and it seems as if these are the only 2 problems once your lude gets close to 10 years old or has alot fo miles/abuse... I think it might be smart to take your intake off and crank your car.. If oyu hear a whistling coming out of your throttle area at idle then its the fast idle THERMOSTAT valve.... If so, cover the lower hole on the left side of the throttle area(on the inside of the circle and on the left side) with your finger and see if theres a vacuum on your finger.. If so, your car should idle down right! Its should also let you know where your problem is... Otherwise, if that doesnt work then you got a wax problem...

 

Its definently the first one you described. So how would i go about replacing my fast idle thermostat valve? Where is it located and where can i get one?

Thanks
Chris

 

okay i just went outside and took my intake tube off and their was a vaery loud whistling but when i covered the lower hole their was a vaccumm on my finger but the car did not idle down right? But i have noticed in messing around with the intake manifold that their is a line that runs from my intake manifold through my map sensor and when i disconnect it the car idles down right but i also get some black smoke out of my exhaust. So with that said do you still think its my fast idle thermostat valve or soemthign else?

Thanks
Chris

 

okay for now i'll just tell you what my invoice from the shop says

"trace problem--replace hot wax valve--came apart inside"

i really don't think that'll help, but somone on here has to know what it is.

 

well its not my fast idle valve. I bought one replaced it and its not it. so i took it back to the dealer and got my money back so anyone else with any ideas?

Thanks
Chris

 

hey this happens to hondas all the time,its usually a vaccum leak so what u can do to find the vaccum hose that is leakin is get a can of carb cleaner and spray them down with the car running,if u see any bubbles or the car starts running good for a little while then its that hose. OR it could be a vaccum leakin in a bigger place ,like on my prelude it was the intake manifold gasket,so i had to replace that.

 

well check this out i have used carb cleacner to clean out the inside of my throttle body and when i do that the car runs fine until the carb cleaner is dried up then it starts to idle crazy again. Also their is a line running from the top of my intake manifold through my map sensor that when i pull it off my car idles down fine but i get some black smoke. Also i have been reading around and one dude said he took his eacv off and soaked it in carb cleaner for an hour then put it back on and it ran fine. So with that said i think im gonna do the carb thing on the vacuum lines but whcih lines should i put it on?

thanks
Chris

 

You should check if u have bent valves, My 98 Prelude had idling problems and i got a valve job and now it runs fine. Get you compression ratios checked out.

 

I think it's the MAP sensor. I have the same problem. I would idle fine when first start up, but after about a minute or two the car starts to oscillate up and down. Unplug the vac line to MAP sensor the car runs normal but throw a code 3. Replaced the MAP sensor and all is ok now. Try another MAP sensor. I also tried fast idle valve didn't fix my problem either. Hopes this help

 

its not my valves or my map sensor. I replaced my map sensor already and its a new engine so its not the valves. it has been compressioned tested and everything already.

 

I fixed it. It was the fast idle valve. thanks for all your help

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cec92lude &raquo;</TD></TR><TR><TD CLASS="quote">well its not my fast idle valve. I bought one replaced it and its not it. so i took it back to the dealer and got my money back so anyone else with any ideas?

</TD></TR></TABLE>

Wait, but you said it wasn't that? How did you go about fixing the problem? Might help others down the line when they start their search... (like me!)

 

Well i put on my new fast idle valve and in doing so i disconnected a line running from my intake manifold to my valve cover and when i put the new fast idle valve on i forgot to rehook up taht line so when i started my car it still idled craxy but i didnt stop to think about it at that time i jsut took off the new valve and put back on the old one. Two days later i was looking at my car being puzzled as to what the problem was and i saw this vacuum line just chilling and i put it back on and it made my idle brop about 1000 rpms but it sitll idled crazy and then i said wait a minute and put abck on the new fast idle valve and made sure to hook back up all hoses and now it runs great. So basically it was the fast idle valve from the beginning i just was stupid and forgot toe hook back up all hoses. So just remember to double check all hoses.

Chris