First i have performed a Search on the site and theirs a lot of good information and i am checking into them.

Ok so here is the story.
Im running a 92 honda civ with a b16A2. I have a ITR Intake....

Basically Im having erratic Idle Issues. When the car is at operating temp the idle changes from 800rpm to 2,500rpm and thats back and forth. Also when its cold its at a steady 3,500rps. So first i thought of the IACV... so i swap out that for a known good IACV. It didn't change a thing. Though when i unplug the IACV it idles at 1,500 with a tiny bit of fluctuation. I made sure all the Vacume hoses ext are all connected. I felt for air leaks, didn't find any.

So currently, im gonna test the FITV and see if their is any extra vacume when the engine is warm. But other than that, im not sure where to go from their. Any info would be helpful!

 

i am basically running the same thing as u are. check all the gaskets. intake manifold, and TB gaskets. and if u remove the tps and remember to use a multi voltage memter to adjust it. also check your ignition timing with a timing gun/light, but basically ignition timing wont make the car idel rough that much.

 

is it cold outside man? cause honestly, older hondas just kind of do that. mine idles really really high when i first start it up in the winter. I couldn't tell you how many rpms since i don't have a tach, then once it warms up it will fluctuate a little sometimes. just make sure your iacv is cleaned out which you said you did, and it should be fine. it used to bother me cause i thought my car was gonna blow up or something, but it's actually supposed to do that i was told, and i haven't had a problem yet.

 

yeah my other civ rough idled when it was cold out. but when it fully warmed it when back to normal.

Yeah i was thinking that possibly that the gaskets on the throttle body maybe defective. I will check the TPS.

 

sounds like a vacuum leak of some kind... probably a bad one. Have it smoked to find it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by austinkli &raquo;</TD></TR><TR><TD CLASS="quote">is it cold outside man? cause honestly, older hondas just kind of do that. </TD></TR></TABLE>

^^^What he said.

My CRX, Civic, and Integra all do the same thing. I read that basically all engines will run rich until it get's to normal operating temperature, it's a basic function of the ECU, and happens on almost all cars, even new, it just sounds louder cause your engine is older :-P

 

mine did it after building out the block... once I had it smoked, we found several vacuum leaks, once corrected... purrs like a kitten...

 

get some starting fluid and spray it around the intake manifold to make shure that the gasket it self isnt bad or a sensor is seeping air. will rev up if bad.

 

Thanks for all the suggestions.
When you say "smoke it out" what do you mean. So i Changed the coolant, made sure there where no bubbles . Changed out the IACV. Their was a sugestion made to cover the TB with my hand and if their was a vacume leak the engine should still run. Im not sure how credible that is but tried it, and the the car died. Next thing im going to try is when the engine is warm im going to cover the FITV and see if its still sucking air through.

let me know if you guys have anymore ideas

 

yea that whole thing about the car will still run, will only work if the vacume leak is big enough. i'd say check your timing, check your tps and map sensor.

 

Yeah, after work im gonna hopefully test the tps, and the FITV today. Hopefully i can get this fixed.

 

It's quite misleading to say that "older hondas will just do that." BS. A hunting idle is indicative of a vacuum leak, not age. Cold idle should be slightly elevated, not at 3500.

It's quite unlikely that a bad IACV is causing this unless it's leaking air. Poor timing will not cause a hunting idle either. Make sure you don't have any ripped gaskets or forgot to connect a hose. I'd be willing to bet that it's a hose somewhere, given the range of idle fluctuation.

 

Yeah i know the b series engines are old... but i agree it shouldn't be that high.

Well here is the status... after changing the IACV, and flushing the coolant the idle has gone down its about 3000 rpm when cold, when the engine is warm it fluxes from 900 to 2000 rpm. So i tested the TPS im getting 5v YAY!!! So i dont think theirs an error with the TPS.

So with the engine warm, i covered the FITV with my finger, and theirs a pretty good amount of air being sucked in. So im gonna take off the TB and tighten the valve in the FITV so no air will pass through their. If that fixes it, im going to buy another. If that dosent work im gonna test the map sensor for vacuum.

I will keep you guys up to date on the status.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by easycheese &raquo;</TD></TR><TR><TD CLASS="quote">So i tested the TPS im getting 5v YAY!!! So i dont think theirs an error with the TPS. </TD></TR></TABLE>

At which point was it reading 5v? Sure you didn't just measure the +5v coming in?

The middle lead is the reading lead and will be typically between 0.4 and 4.6V. The sensor is a variable resistor, so as you open the throttle, the reading should increase linearly towards about 4.5v. Check that again.

 

Yeah i tested both, all is working on the TPS, but i did find the issue for sure. Its deffinitly the FITV, with the engine warm, its sucking in air like its cold. So im just gonna close the valve make sure that works and then buy a new one.

 

You might not need to buy a new FITV if when you tighten it, your surging idle goes away. I believe I've heard of them coming loose and tightening fixes the issue. You could also clean the FITV and see if that works.

 

yeah if i tighten it, and it works im just going to buy another one. I will keep you guys posted on the progress

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SilverBulletY8 &raquo;</TD></TR><TR><TD CLASS="quote">sounds like a vacuum leak of some kind... probably a bad one. Have it smoked to find it.</TD></TR></TABLE>

Agreed, try putting your hand over the throttle body while its running and if it doesn't die you have a vaccuum leak. Did you replace your Intake manifold gasket with the itr I/M install?

 

Yeah i have tried all that, i know its not a vac leak. I am 98% sure its the FITV

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by easycheese &raquo;</TD></TR><TR><TD CLASS="quote">Yeah i have tried all that, i know its not a vac leak. I am 98% sure its the FITV</TD></TR></TABLE>

That is, essentially, still a vacuum leak, whether it's on the inside or the outside.

 

Well guys i have found the issue.
Turns out the plunger inside the FITV was not screwed in. So i just screwed it closed. Its now idling at 900rpm even. So all is well.

Thanks for all the suggestions