I'm prepping an 89 Civic Si for SCCA Street Touring class. Just recently after the car warms up the idle will fluctuate up to 1600 rpm then back to 700 rpm on a reqular basis every 2 or 3 seconds. Sometimes the problem will go away after a while. It sound just like when I used to run a full race high lift cam in Chevy small blocks. But honest, it stock.

Engine has stock ECU, 4-2-1 headers, supertrapp dumping three feet behind the cat, light wt UR race underdrive crank pulley, and a small 6 lb (actually its 7.3 lb but thats another thread) Braille battery. Engine is otherwise stock.

Any ideas on the idle problem. Thanks for any help you can offer.

 

clean tthe idle air control valve on the back of the mani, just take it off and spray it with carb cleaner, let it dry and your good, put it back on

 

^^x2

if the problem continures i may need to replace it

 

or or, distributor is is starting to fail, does it stumble on acceleration
Check your fuel pressure and vacuum lines

 

try a new 02 sensor.. this fixed a rough idle/misfire on my crx once.

 

I've seen them do this when intakes are installed without resetting the ECU, etc. Did the problem just randomly start or did it coincide with anything that was done to the car?

 

also check for air in the coolant level.

This will give the same issue as the fluctuating idle.

 

ok i am having the same problem but myn is from about 2000 to about the same and i have just got my car back on the road swaped in a d16a1 put on a ram style intake, newer ecu,new dissy, and i am using a f22 tb by what i was told. It dosesnt feel as if all the power is there and when i first started my car with this engine it has been doing this but has slowly gotten better on its own but not fully could this be the idle air control valve or something else

 

mine does it only on cold days.
Somone said to try seafoam

 

even an oil change can get rid of it

 

well i have freash oil and filter only a 150 miles on them and a friend of myn told me the same on the seafoam

 

You should clean it either way, a can of carb cleaner is not expwnsive and it's not had to do

 

My 88 hatch did this too. I cleaned the IAC with carb cleaner, blead the coolant system and still had the problem. My friend also told me to seafoam it but that just wasted ten bucks and didnt do anything. I eventually went to the junkyard and found a newer IAC that was in working order and havent had the problem since.

 

thanks projekt good info i will do that today and i wasnt doing that to get around it i just changed the oil before i put that engine in and it does the idle **** so...

 

lets start with "i have search all forums and never seem to find this specific problem, 2nd my english isint the best.
let get started i bought this crx a couple months ago the first night i drove it home i was perfectly runing cherry.
cost me 700 so eventualy it came that time when registration transfer titles and so on , since i only started driving this car a week ago its been iddleing so ruff, like ex whe my vtech switch is on the crx iddles way below 700 rpm. turning it off help to warm the car seems to go back up to around 850 ,

another thing is power drain i always have to disconect my battery becouse it dies out in the nxt morning, when im at a stop and i stop put it in nutruel and turn my high beams on the cars iddle drops a little ???

but my main concern is the idlle check out my video no rush , at all i mean its running but smog is around the corner , tHANKS n advance,

block- d18y8
head-idk its vtech thoe for shure
-tranny - si
ecu- idk never check it
battery duralast= fail
===========================================
video <embed width="440" height="420" type="application/x-shockwave-flash" src="http://v6.tinypic.com/player.swf?file=2exbuk1&s=6"><br><font size="1"><a href="http://tinypic.com/player.php?v=2exbuk1&s=6">Original Video</a> - More videos at <a href="http://tinypic.com">TinyPic</a></font>

if not working video here http://tinypic.com/r/2exbuk1/6

 

No problem crxjarred. I did everything i could to get around buying a new one and some of the ideas worked for a week or two but the problem always returned until i replaced the IAC all together.

 

well i cleened it today not much came out of it but i put it back on and it hasnt done it yet but we will have to see but now i think my damn thermastat is bad its problems after problems

 

If there werent problems it wouldnt be an ef.

 

the fast idle valve will be your next attempt.

 

What's that? And how much is a new iacv?

 

Brand new IACVs can be expensive. The one for the ef is like two hundred bucks brand new. I got mine from the junkyard for around thirty bucks and never had a problem with it.

 

FITV= Fast Idle Thermo Valve.
- where the coolant lines run directly under the TB port.
- Pop it open ans screw the lil white nut in til its snug. and NOT tight.

 

Oh, you know I bypassed my TB coolant lines =]
Supposedly you get more hp.

Anyways. I seafoamed my moms car this weekend. No longer a skeptic, can't wait to dio it on my car.
There was a little bit left and I used it to clean my iacv, seems to be working fine now.
I have to say though, my idle started acting up after I sprayed throttle body ckleaner in my intake, so it probably clogged my iacv

 

You don't really get more hp, you just prevent heat soakin your throttle body. They are nice to have in winter. I reconnected the coolant lines on my xbs tb for winter. Apparently my xb will not run right if its too cold outside.

And being our hondas at least 20 years old, I'd say that's not a bad option to have for winter!