So i had a post a while back. i have not had time to get around to getting this 100% so i had to deal with the idle hunting.

got some time now so here it is

1998 honda cx hatch

jdm b16a Gen2


car idles cold fine

car kind of idles on warm fine but has two issues, once throttle is slightly opened and closed ( well, percentage from 1% to W.O.T) once throttle is closed again engien will hunt between 1000rpm and 1500rpm for some where between 30-60 seconds then calm back down to about 800rpm

now i noticed if i turn the car on, let warm up from idle, every single time the fan kicks on the engine begins to idle erratic again (1000-1500 rpm) until the fan kicks off.

what i have doen so far:

There is NO CEL!
cleaned fitv
cleaned eacv
checked vacuum lines
cleaned throttle body & replaced gaskets
coolant flush (although i forgot to tilt the car forward when refilling coolant and idling to flush air pockets)
checked ign. timing.

so my thought was maybe the coolant temp. sensor???

what do you guys think is causing an erratic idle when the coolant fan comes on because i do believe it is linked to the problem with the throttle as well, whether they are the same or two different problems, it is extremely consistent .

 

so i went and did some test, coolant temp sensor is within spec (286 ohm) on after 3 fan activations so obviously the engine is to temp.

i went nuts and checked every sensor i could just for the sake of it, all within spec (i did not check the tps yet though)

I was roaming around and found on user: RonJ@HT in his sig.

apparently plugging the fitv hole on cold start will smooth or kil the idle. i know this is not a issue as the cold start is great and a while back i cleaned and reset the fitv piston.

Now the Eacv is another story, i plug the hole and the jumping idle calms down, 800 ish rpm, lil high BUT none the less, blocking the eacv air passage seems to be the fix.

I cannot process in my brain as to why or what the fix it? casue does this not mean that the eacv is working correctly??
the car did not stall when plugging the eacv hole in the TB so... some one please give me some insight i am clearly not understanding something, or if this be the case, then what is a possible problem here.

if in basic theory, erratic idle is caused by an air leak/to much air. what else could cause this, i feel quite confident my vacuum lines are good, checked the pcv line on the top of the intake and chocked it to see of the pcv was malfunctioning, no fix.

not checking the tps yet, but could that be such a huge reason as to why it is fluctuation? if so then why is the eacv port, when plugged, calming the engine speed/idle down and not stalling???

 

....... help... -_-

 

well bump

double checked everything i have gone over before to make sure i did not miss something.

-cold idle is fine. engine warms up, rad fan kicks on and idle starts hunting.
fan stop's idle calms down or stays hunting.

-1% or more throttle, idle hunts.

- when engine is hunting i plug the eacv port in the TB, idle comes down, hunting stops.
the car does NOT die. does this means the eacv is working correctly or not? I thought it meant it does and it does not if the engine dies?

this is the second eacv i have replaced on it, im gonna try and get another one becasue i have no idea.

would someone(s) PLEASE!!! help.

 

Did a tps test, .48 closed, 4.53 WOT

 

took off the fitv to check the plunger for vacuum leaks it was ever so slightly turned out like maybe 1/8th of being fully seated so i screwed it fully in to seat. re-installed.

still hunting

cant believe almost 200 views and NO ONE has any idea. ive been searching to as far back as 2003 on threads like my problem and all of them have no solution because the op never post's back.

is H-T really this empty quiet now?

 

no fix yet bump