hunting/high idle

[monda2]

Hi All

I know there are plenty of threads regarding hunting idle, I have read most of them and tried some of the suggestions, thought I would share my issues just incase someone could shed some light : )

So, I have a B16A - all standard honda ecu

On first start up it idles at 2300rpm approx for 30sec then starts hunting from 1000-2000, can use throttle to rev but once stop using throttle it will go back to hunting, once she warms upto 70degreesC approx idle drops to around 1400rpm - hunting stops most of the time, when temp reaches 85-90 degrees C it occasionally hunts but not consistently.

I have adjusted the TPS to 4.5v at WOT and 0.48v CT since doing this it seems to be idling higher than before (was normal 800-900rpm when hot)

I have also taken off the IACV (on back of inlet mani) and cleaned and chkd to see if still works - seems to

Made sure there are no air leaks i can find anywhere.

Do I require the Fast Idle thermo valve (FITV) some peeps seem to remove it and blank it off, my way of thinking is I would rather keep everything on as per honda designed it?

Another issue was when I last took it out (before calibrating tps) let it warm 70C degree started to take off and engine had no power, wasnt missing just had no go, nearly stalled, once it warmed up a little more it seemed to fix itself??

A little stumped?

Have a trackday next wend keen to sort it out before than

Any help appreciated

Cheers
Ben

[Civic89]

Mine was doing the same thing, At about the same revs. Alot of mechanics said it is more than likely a vacuum leak somewhere, So check all your little hoses.
But what mine really was, was apparently "A little screw in the intake manifold near the throttle body had fallen out"

[TODA AU]

You probably need to tighten the plastic seat within the thermo fast idle valve.

[monda2]

Hi Toda, I checked to see if the fast idle valve (pictured below) was working by letting the engine run until normal operating temp then placing some tape over the bottom hole in the throttle body, to check if this made any difference to the idle - nothing happen, after doing this do i still need to check the plastic seat? could this still be the problem? I am assuming I remove the 3 bolts and pull it apart?
cheers

http://i51.photobucket.com/albums/f386/benmin/FITV2.jpg

[TODA AU]

Hi Toda, I checked to see if the fast idle valve (pictured below) was working by letting the engine run until normal operating temp then placing some tape over the bottom hole in the throttle body, to check if this made any difference to the idle - nothing happen, after doing this do i still need to check the plastic seat? could this still be the problem? I am assuming I remove the 3 bolts and pull it apart?
cheers

If that's the case, probably not then but it couldn't hurt as these thing are notorious for stuffing out.
Just out of curiosity, is the idle bleed bypass screw wound out or in?

[monda2]

Ok, sorry bit of a newbie to all this where is the idle bleed bypass screw? Hve u a photo? Is it supposed to b wound out, guessing not?

How tight can u tighten the plastic seat in the thermal fast idle valve? I can screw it in quite a bit more than way it was? All the way until it stops or does it have to b a certain depth in?

[TODA AU]

Ok, sorry bit of a newbie to all this where is the idle bleed bypass screw? Hve u a photo? Is it supposed to b wound out, guessing not?

How tight can u tighten the plastic seat in the thermal fast idle valve? I can screw it in quite a bit more than way it was? All the way until it stops or does it have to b a certain depth in?

The idle bleed bypass should be most it all of the way in.

The fast idle valve plastic seat needs to be seated & tight.

[monda2]

thanks toda but where is the idle bleed bypass screw? on throttle body??

the plastic seat so that means all the way in and tight, wont that stop air passing through?

[TODA AU]

http://i639.photobucket.com/albums/uu115/RonJ_HT/picture_5153.jpg

Bleed bypass screw is the idle adjusting screw in above pic.

The fast idle valve plastic seat need to be seated & tight.
It may look like it won't work like that, but it is correct.
The centre plunger is controled by a wax thermostat, it opens (reduces spring tension) when cold.
The air will suck past it until hot, then it will seal properly.
But the seat needs to be tight. :thumbsup:

[monda2]

thats great thanks alot Toda appreciate it, cheers

[monda2]

well i have fixed the hunting issue, well very nearly, it seems to hunt (barely 20rpm) when the headlights are on??? seems more like an electrical issue now? the battery did go flat a last week and now is ok? not sure whats going on with that

The idle was still a little high so I turned the idle/air screw down (see below) it seemed to have some sealant on the thread as Iam assuming it this was to stop it vibrating?? does anyone know?

http://i51.photobucket.com/albums/f386/benmin/idlescrew2.jpg

The only slight issue now is it seems to get hotter (was reaching 96C degrees) when not moving (idling) once on the move it went down to 87ish C degrees, was thinking of fitting a higher pressure cap, have a 13psi, will go for a 15, what do peeps think?

[monda2]

Hi Guys

Thought I would bring back my thread

Iam still having problems with the hunting and high idle, I wanted to check something first, the below photo (not the greatest) shows the throttle body (b16a1) when the engine was running and hunting I blocked the top hole up which stopped the hunting (was still idling high), when blocking the bottom hole it didnt make a difference to the hunting

http://i51.photobucket.com/albums/f386/benmin/TB2.jpg

Does this mean the EACV could be stuffed? rather than the FITV?

I have removed the TB as it needed a thorough clean and also planning on hopefully ordering new seals/o-rings for the EACV

any help appreciated
thanks

[xclusive_eg8]

something no one mentioned...do you have air bubbles in your coolant?? mine was odd like this till i did a good bleed...and yes FITV is really only needed for colder climates like for instance Japan where it snows and car needs to heat up asap, it can be blocked off

[monda2]

Thx exclusive, but yes I have bleed the system a few times to no avail

[blastnpast]

Try this or watch this it's pretty helpful

http://m.youtube.com/index?desktop_uri=%2F&gl=AU#/watch?v=L788jKEVblY

[blastnpast]

If you still have this issue try:

P.s if your like me and don't have the FITV And that other stuff just try all the steps u can :(

Extract from:http://ef-honda.com/ben/Badidle.php


First things first, don't skip any of these steps. From what I have read (and experienced) usually small dumb things cause these problems so don't overlook anything. Also refer back up to the pictures if need be.

1) Check your vacuum routing. On the underside of your hood there should be a vacuum diagram. If there isn't a diagram under there, there is one in a Helms, Chiltons, or Haynes manual for your car (you should have one of these anyway). Remember, ANY extra air will confuse the ECU. Check for cracked or bad vacuum hoses. If in doubt just replace the hose, they are cheap.

The PCV valve could also be the culprit. Take it out and examine it. If it is cracked it could be causing a vacuum leak. Replace the peice if you arent completely sure it is ok (the helms/chiltons/haynes manuals tell you how to check it).

2) Check to see that your throttle plate is closed all the way. Take your intake off at the TB and check to see that nothing is blocking the plate. If nothing is in the way and it isn't closed all the way, loosen your throttle cable.

3) Check to see if the nuts holding the TB and the IM on are tight, this was the source of my idle problem. If they are loose, tighten them.

3.5) Check the Idle screw. Its on the top of the TB right next to the red vacuum line in the first picture. Its a flat-tip screw and most TB's have it epoxied over. If your screw is not epoxied over try adjusting it.

4) Bleed your coolant. Some air bubbles may throw the FITV off and keep the valve open.

5) Take the 3 10mm bolts out of the FITV (you don't have to take off the coolant lines). Then take off the 2 8mm bolts off the plate on the back of the FITV. Once the plate is off you will see a white plastic thing, screw that all the way in. This causes a TON of people's hunting idle problems (it's a source of a vacuum leak). Put the FITV back on and start the car up. If it still idles bad go on. Here is a writeup on the FITV.

6) Clean the IACV screen(s). See Oz's write up on G2IC.

7) Make sure your car is completely warmed up. With it running, take the intake off the TB. There are 2 holes right in front of the throttle plate, these are the holes that feed the IACV (top hole) and the FITV (bottom hole). With your finger, cover up the bottom hole (it should NOT be sucking if your car is warmed up). If the idle goes down the FITV is to blame, either get a new one or take it apart and screw the valve completely closed (I have only read of people doing this, so I don't know exactly how. Also, you will have to keep the engine speed up yourself when the car is cold).

Next cover both holes up with your fingers. The car should sputter and die (or almost die). If it does then the source of your crappy idle is the IACV. Replace it. If you want you can test the IACV. Shut the car off and put + battery voltage to the blk/yel terminal (on the valve) and momentarily touch ground to the blu/yel side. When doing this the valve should click, if it doesn't, replace it.

If, when covering both holes the car still has a high idle, you have a vacuum leak somewhere. Again check the IM and TB nuts. You can spray carb cleaner around those areas and if any gets sucked in (the engine will rev) you have found your leak. Another source of vacuum leaks are where the FITV and IACV connect to the IM. Either replace the gaskets or use silicone gasket sealant.

8) If nothing has worked you should test your TPS. Probe the middle wire on the TPS plug (with the key on but not running, and the plug still connected to the sensor) with the + probe on the volt meter, and the neg probe to ground. You should have .5v with a fully closed throttle plate and 4.8v with it wide open. If the TPS is off, replace it. My TPS was .425v to 4.55v and it idles fine now so I don't know how big the margin of error is. Also, it is pretty rare for these to go bad.

9) If, still, nothing has worked you might want to try a new ECU. This also is very unlikely, but worth a try.

10) If it still idles bad, go through the steps again.

[monda2]

Thanks blastnpast much appreciated will give it a go