IAC Installation

[CAV3MAN227]

-I once again have IAC (Idle Air Controller) problems. I have a couple heads to swap in and out. Right now, the head is turned almost all the way clockwise, towards the firewall, just to get it to idle at 500 rpms. The complete opposite direction of where its suppose to be. I should note, that I just installed an almost new TB. Idle screw and TPS has not been tampered with.
-So my question is, is there a proper way to install the IAC head? Is there some special install method? If someone could point me in the right direction, I'd greatly appreciate it.

-Joe

[CAV3MAN227]

-Well I just discovered clockwise is open. When putting the IAC head back on, where should everything be positioned?

-Joe

[Legacy777]

The head is usually positioned in the middle some where. Is your idle too high or too low?

[CAV3MAN227]

-Right now, to low with occasional high hanging idle. Idles about 450-500 with no load.

-Joe

[Legacy777]

Are you using the tach on the dash or a stand alone tach to check engine rpm? If you're using the tach on the dash, it is very common to misread the tachometer hash marks. The lighter mark just below the 1 is actually the 750 rpm mark, not 500 rpm. The heavier mark just above the 0 is the 500 rpm mark. You can see that in this pic of the tach.

http://main.experiencetherave.com/subar ... G_5845.JPG

So if you're using the dash tach, your idle is probably around 650-750 range. Do you have any specific issues with it idling where it's idling, other than the occasional high hanging idle?

[CAV3MAN227]

-I'm using the tach on the dash. When the car is warmed up and idling correctly, as you call it, it idles at the 750 rpm mark. Depending on each startup though, it can be different. Its like almost every other time I start the car, it will idle around the 1300 rpm range. Then when I hit the throttle, rev it up, idle will hang around 3000 rpms. Before changing the throttle body, it was doing this:
https://www.facebook.com/photo.php?v=63 ... =3&theater
-To me it seems the iac is sticking, but if I take the two screws out, take the iac head off, I can move that male piece with no issues. My question is, how to put the iac head back on, if there is some specific method of doing so. I'm pretty sure its the iac giving me my idle issues.
-Friends keep saying its a vacuum leak. When I pump the brakes, it the driveway at idle, it brings the idle down quite a bit, I could probably kill the motor if I pumped them enough times. But I read in the chilton's manual, 17-22 inches of vacuum is normal depending on elevation, and mine is around 19 at idle so I don't think it can be a vacuum leak.
-I just don't see how this can be a vacuum leak. The idle issues all started when I changed my spark plugs. I might be able to get my hands on a whole new iac unit, so was thinking of pulling the intake manifold, go through everything and check for any issues.

-Joe

[Legacy777]

I normally suggest starting with what has changed. I know you said you just replaced the spark plugs, but did you take off any of the intake components or move around anything that might be contributing to your idle issues?

Applying the brake a bunch of times shouldn't cause the engine to stall....or so I would think.

Regarding the IAC top, there is no guideline on how to adjust that. It is not meant to be removed. Another thing you can try is checking the wiring from the IAC to the ECU to make sure it's good and that you have good battery voltage going to it. Have you tested the coils on the IAC top to see if they're in spec?

http://main.experiencetherave.com/subar ... C_Diag.zip

[dankberries]

Maybe the screen/diaphram thing inside the IAC got damaged ? Just a thought.
I would, if you can, do a boost/pressure leak test to make sure everything on the manifold is sealed good.

[alexandermf]

Ya that screen web thingy can sometimes fall out or be damaged without you even knowing

[CAV3MAN227]

I normally suggest starting with what has changed. I know you said you just replaced the spark plugs, but did you take off any of the intake components or move around anything that might be contributing to your idle issues?

-Well, yes. It all started when I had the bright idea to double up on hose clamps where I could for the fmic piping. So I took it all apart, changed out my spark plugs and put it all back together, hence where the problem started.
-Long version: ic pipes came off, took the spark plugs out, noticed I was running the step colder plugs this whole time (bkr7e), with no issues I must add. Had an old set of plugs, bkr6e-11, so I put them in, hooked up all the ic piping and problems started. So next, went to the store, got some brand new bkr6es-11's and put them in. Ever since, I have been having these idle issues. For a while there, I was coming up with codes 22, 24 and 41 but I believe I have fixed those as I have not seen the cel come on now for quite some time.

Applying the brake a bunch of times shouldn't cause the engine to stall....or so I would think.

-I tested this in the girlfriend's 2001 25rs and pumping the brakes made her idle rise about 100 rpms, hmmm...

Regarding the IAC top, there is no guideline on how to adjust that. It is not meant to be removed. Another thing you can try is checking the wiring from the IAC to the ECU to make sure it's good and that you have good battery voltage going to it. Have you tested the coils on the IAC top to see if they're in spec?

-Well thanks to a local friend, I came up on a whole new iac:

-I'm going to install this right now and go from there and see where this gets me.

Maybe the screen/diaphram thing inside the IAC got damaged ? Just a thought.
I would, if you can, do a boost/pressure leak test to make sure everything on the manifold is sealed good.

-I will check this once I get mine off.
-Thanks everyone for their input.

-Joe

[CAV3MAN227]

-Well, believe I had a bad IAC unit this whole time. I put the new one in, made a few adjustments and car runs better than ever now. Here are some pics of the install:
















-Joe

[Legacy777]

Glad to hear the new IAC valve fixed your problem!

[CAV3MAN227]

^Thanks for your help Josh, really appreciate it. I wouldn't be driving this car if it wasn't for these forums.

Regarding the IAC top, there is no guideline on how to adjust that. It is not meant to be removed. Another thing you can try is checking the wiring from the IAC to the ECU to make sure it's good and that you have good battery voltage going to it. Have you tested the coils on the IAC top to see if they're in spec?

-Also, I did test the IAC head and was getting proper voltage to it.

-Joe

[Legacy777]

You're welcome.