This happens randomly. Sometimes, the fluctuation is so obvious, sometimes not.

Sometimes even after I reach operating temperature and idles at 750-800rpm, the fluctuation shows up.

1. Some people say uberdata always has problems with this, but I already tune it to 14.3-14.7 AFR at idle.
2. Based on my research and also I had this problem in my friend's civic, and was solved by spraying some carburetor cleaner to the IACV hole, it fixed the problem. I did this to mine, didn't make a difference. Maybe I should open the whole IACV and clean it up?
3. I know what it's doing is similar to when there is an obvious vacuum leak. I checked mine and so far it's ok, but I can double check on this.

Any suggestions or similar experiences?

 

Ignition timing. Don't have too big of a jump in timing in the rows immediately after idle.
16
16
16
16
20
26

will generally idle better than
16
16
16
16
24
29

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by elpiar &raquo;</TD></TR><TR><TD CLASS="quote">This happens randomly. Sometimes, the fluctuation is so obvious, sometimes not.

Sometimes even after I reach operating temperature and idles at 750-800rpm, the fluctuation shows up.

1. Some people say uberdata always has problems with this, but I already tune it to 14.3-14.7 AFR at idle.
2. Based on my research and also I had this problem in my friend's civic, and was solved by spraying some carburetor cleaner to the IACV hole, it fixed the problem. I did this to mine, didn't make a difference. Maybe I should open the whole IACV and clean it up?
3. I know what it's doing is similar to when there is an obvious vacuum leak. I checked mine and so far it's ok, but I can double check on this.

Any suggestions or similar experiences?</TD></TR></TABLE>

A few items to note:

Using a different IACV than was intended for the ECU (using a P28 on an Integra for ex.) can sometimes lead to idle fluctuations since the duty cylces differ slightly from one IACV to the next, this is why many programs have the duty cycle slider option to compensate.

Check your fast idle thermo valve (PM M.A.R.C. about this)

Check your TPS voltage and ensure it's at or near .45v, anything over .05v more/less will tend to throw the ECU for a loop and result in erratic idle.

 

check your fast idle valve plunger under your TB.

 

this will also happen from air pockets in the coolant...the fast idle valve has a wax pelet like a thermostat so it needs to get hot to click the valve shut ...

 

Ok I will look into cleaning IACV and FITV, i don't know where the fitv though, anyone has diagram?

 

it is most likely right under your throttle body and will have 2 coolant lines and 2 12mm bolts holding it in...you can take it off and shake it to see if it rattles ...if it does its most likely broken.

before you take it off see if its working...take the upper charge pipe off and start the car...look inside the throttle body you will see 2 holes infront of the throttle plate...

the one towards the firwall is the air supply for the idle air control and the bottom is the air for the fast idle valve. let the car heat up and feel if theres suction on the hole for the fast idle ...if there is its not fully closing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D@nnY &raquo;</TD></TR><TR><TD CLASS="quote">this will also happen from air pockets in the coolant...the fast idle valve has a wax pelet like a thermostat so it needs to get hot to click the valve shut ...</TD></TR></TABLE>

Never bleed my coolant before. WHere is the bleed valve on B18C1?

 

The fast idle valve has a copper looking cover over it. Remove that cover and you will see plunger/nipple(kinda looks a belly button with two slots on opposing sides of each). You then inspect it if the plunger has baced out, if it is, turn the plunger back in.