Idle air control valve
11-01-2004, 12:18 PM
#62
1.5 BAR
Join Date: Aug 2003
Posts: 1,068
Re:Idle air control valve
your IACV will cause lots of annoying crap! For instance my IACV is F'ed up... cold the car would bounce from 1200 to 2500, with a check engine code which I believe is #44, then once it got warm it would idle 490-520. what you should do is stick a staple in each side of the little blue service connector hidden up inside behind your glove box, and then turn the ignition to on and count how many blinks your CEL does, LONG blinks mean 10, and then short blinks are 1 , in a civic I believe it's #44 for IACV, if thats what the problem is foresure then take it off and check out the figure 8 o-ring, if it's flattened out then it may be a wise choice to get a new one seeing as how Honda will probably only want $1 or $2 and hopefully that will fix it, HOWEVER....... if it dosen't then there is a way to ADJUST it by turning a little 5-point allen bolt on the side of it. Now if that dosent work then it is probably seized up inside so what you need to do is, sneak into your sisters bedroom and steal the $2.50 that she's got hidden under her pillow and has been saving up from Whoring herself out, go to your local Gun & Ammo shop and purchase some shell's, go back home borrow your dad's gun and shoot the ---- out of that damn IACV thats been giving you so many problems. (hey, if nothing else you'll feel alot better!)
11-06-2004, 11:13 PM
#63
0.5 BAR
Join Date: Sep 2003
Posts: 197
Re:Idle air control valve
I havent read this whole post but
alot of my idle issues were solved by PROPERLEY resetting the ecu. that is, letting the engine warm up, pulling the fuse for 30 seconds, then start the car and let it IDLE for 10 minutes. then shutoff car and restart.
alot of my idle issues were solved by PROPERLEY resetting the ecu. that is, letting the engine warm up, pulling the fuse for 30 seconds, then start the car and let it IDLE for 10 minutes. then shutoff car and restart.
12-01-2004, 01:26 PM
#64
3.0 BAR
Join Date: Dec 2004
Posts: 2,133
Re:Idle air control valve
I had a similar problem not too long ago.
My idle was around 2200 steady at all times. I just replaced my IACV with a used one and idle is back down to about 1050-1100. The only problems I have now with it is at cold startup my ilde doesnt go straight to the warmup idle (1500-2K). Instead it stays at warm idle fo a minute or so until it warms up slightly.
Basically IACV fixed my probelm though. I looked inside my old IACV and the blue thing inside it was all torn up looking.
My idle was around 2200 steady at all times. I just replaced my IACV with a used one and idle is back down to about 1050-1100. The only problems I have now with it is at cold startup my ilde doesnt go straight to the warmup idle (1500-2K). Instead it stays at warm idle fo a minute or so until it warms up slightly.
Basically IACV fixed my probelm though. I looked inside my old IACV and the blue thing inside it was all torn up looking.
12-16-2004, 01:05 PM
#65
0.5 BAR
Join Date: Aug 2004
Posts: 79
Re:Idle air control valve
once my idal was boging and and the headlights would dim when I steped on the brake, all that I did to fix it then was tighten the battery wires and made sur I had good ground on conections. I FUCKN HATE IDAL PROBLEMS!!!
12-26-2004, 03:23 AM
#68
0.0 BAR
Join Date: Dec 2004
Posts: 34
Re:Idle air control valve
Hey got this off HT- might help:
Bad Idle Troubleshooting
This is mostly for high and roaming idles but may work for low idles as well.
First, terms:
TB – Throttle Body
IM - Intake Manifold
IACV – Idle Air Control Valve (also called the Electronic Air Control Valve or EACV)
FITV – Fast Idle Thermo Valve
TPS – Throttle Position Sensor
I finally got the swap (b18a) in my civic but unfortunately when I started it up it idled at 3k then when it warmed up it had a hunting idle from 2k to 2500 rpm. I stood over that thing for 3 days, testing and scratching my head. On top of that I did a TON of searching on the h-t, hybrid boards, and on here. I hope what is contained within helps someone. Maybe they wont have to go through as much work as I did.
The idle on our Hondas is a tricky thing. It is controlled by two main sensors: the FITV and the IACV. The FITV is a mechanical valve that is controlled by coolant temperature (there is no ECU plug to it). When the coolant is cold the valve is open and letting air into the IM through a hole in the TB before the throttle plate. This essentially creates a small vacuum leak which in turn lets the motor idle higher than normal (supposed to be around 1500-2k for warming up). As the coolant warms up the valve closes and no longer lets air in through the hole in the throttle body. All the while the IACV, which is ECU controlled, is letting small amounts of air into the IM through another hole in the TB. Any amount of extra air the ECU is not expecting will confuse it and you will get either a high idle or a roaming/hunting/fluctuating idle. On to the troubleshooting.
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.
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.
6) Clean the IACV screen(s). See Oz’s write up elsewhere 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.
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.
I really really hope this helps someone out. It was a pain to have this mysterious problem and very little info on how to go about troubleshooting it. Comments or suggestions are welcome.
Bad Idle Troubleshooting
This is mostly for high and roaming idles but may work for low idles as well.
First, terms:
TB – Throttle Body
IM - Intake Manifold
IACV – Idle Air Control Valve (also called the Electronic Air Control Valve or EACV)
FITV – Fast Idle Thermo Valve
TPS – Throttle Position Sensor
I finally got the swap (b18a) in my civic but unfortunately when I started it up it idled at 3k then when it warmed up it had a hunting idle from 2k to 2500 rpm. I stood over that thing for 3 days, testing and scratching my head. On top of that I did a TON of searching on the h-t, hybrid boards, and on here. I hope what is contained within helps someone. Maybe they wont have to go through as much work as I did.
The idle on our Hondas is a tricky thing. It is controlled by two main sensors: the FITV and the IACV. The FITV is a mechanical valve that is controlled by coolant temperature (there is no ECU plug to it). When the coolant is cold the valve is open and letting air into the IM through a hole in the TB before the throttle plate. This essentially creates a small vacuum leak which in turn lets the motor idle higher than normal (supposed to be around 1500-2k for warming up). As the coolant warms up the valve closes and no longer lets air in through the hole in the throttle body. All the while the IACV, which is ECU controlled, is letting small amounts of air into the IM through another hole in the TB. Any amount of extra air the ECU is not expecting will confuse it and you will get either a high idle or a roaming/hunting/fluctuating idle. On to the troubleshooting.
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.
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.
6) Clean the IACV screen(s). See Oz’s write up elsewhere 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.
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.
I really really hope this helps someone out. It was a pain to have this mysterious problem and very little info on how to go about troubleshooting it. Comments or suggestions are welcome.
01-13-2005, 03:40 PM
#69
0.5 BAR
Join Date: Feb 2004
Posts: 146
Re:Idle air control valve
That right there works like a charm! Thanks man.
I cut out a piece of sheetmetal,stuffed it in between and sealed it today.
All that i had to do is crank up the idle screw a little and it's all good now.
Added after a day of driving:
This'"trick" messes up the cold start,so it'll fire up and then die because the idle is no longer controlled.
However...this is in around freezing conditions and after a minute of driving it idles great.
Also fuel consumption went up..wich is a nice side effect for me personally since i don't have any fuelmanagement while boosting.
I cut out a piece of sheetmetal,stuffed it in between and sealed it today.
All that i had to do is crank up the idle screw a little and it's all good now.
Originally Posted by sccaeg
I didnt read all of the posts before, but heres how I fixed my IACV. wait until the engie is cold. Unbolt the IACV but DONT take it off. You might wanna disconnect the sensor, it just makes things easier. Get a pop, soda, coke, beer whever you want/whatever you call it, can. cut it so you have about a 3'' by 2'' rectangle. make sure its clean. place the can between the IACV and the intake manifold. it will take care of your problem. (its workin for me) it bacially bi-passes the IACV. you may have to re-adjust your idle elsewhere, but it works!
http://www.villagephotos.com/viewimage.asp?id_=8740435
http://www.villagephotos.com/viewimage.asp?id_=8740435
This'"trick" messes up the cold start,so it'll fire up and then die because the idle is no longer controlled.
However...this is in around freezing conditions and after a minute of driving it idles great.
Also fuel consumption went up..wich is a nice side effect for me personally since i don't have any fuelmanagement while boosting.
01-17-2005, 12:44 PM
#70
0.0 BAR
Join Date: Jan 2005
Posts: 2
Re:Idle air control valve
I have a ls vtec and i cant figure out why my cars idle is messed up. at times ill b cruising and when i come to a stop it sounds like it wants to die. for the most part it idles perfect then out of nowhere it will drop to like 250-300 then bounce back up. Anyone have any idea wat that is? wat should i do?
