Cascade Crew

pathology knight · Posted: Fri Sep 21, 2007 7:46 am Post subject: high idle

hey guys-
my 89 t/a is idling pretty high. is there a manual adjustment?
i was gonna take it back to the shop, but i figured i would ask just in case there might be something easy i can do.

oh...it has a 350 tpi.

Dewey316 · Posted: Fri Sep 21, 2007 8:42 am Post subject:

What is it idleing at?

Xophertony · Posted: Fri Sep 21, 2007 8:56 am Post subject:

no manual adjustment. you have to do a few things. but there is a way to set base throttle position.

Twilightoptics · Posted: Fri Sep 21, 2007 9:04 am Post subject:

There is a manual adjustment.

But in stock form, if your idle is high, it's probably something else... bad IAC, stuck throttle blades, etc.

Dewey316 · Posted: Fri Sep 21, 2007 9:06 am Post subject:

There is also cold start stuff that should go to a high idle, there is also the option that the factory tach is just off, that is why I am wonder how high it is idling at.

Xophertony · Posted: Fri Sep 21, 2007 10:18 am Post subject:

Dewey316 · Posted: Fri Sep 21, 2007 10:20 am Post subject:

When the motor is cold, it idles higher until it warms up. If it thinks it is still in the cold process, it will idle high. On a cold winter day, go start your car, it will idle at say 1200rpm, until it warms up and the idle drops to the normal 650rpm. It is basicly the "choke" on the EFI cars.

--John

Xophertony · Posted: Fri Sep 21, 2007 10:42 am Post subject:

i think that function on my car is broken. sometimes it will just decide to idel at around 1200 on it's own acord. this always happens after a restart when the car is hot. happened last night. pisses me off. Sad

Twilightoptics · Posted: Fri Sep 21, 2007 10:48 am Post subject:

Usually you can get a "flare up" when you restart the engine. It's to keep the motor from stalling. If it doesn't come down on it's own... You've got a sticky throttle, or the IAC isn't closing enough because it's dirty, bad, stuck, or the TPS may be calling out for a higher IAC because it's out of adjustment.

Those are the typcial.

pathology knight · Posted: Fri Sep 21, 2007 11:19 am Post subject:

i'd be happier with a 1200 idle.
as my t/a is my 3rd car, i don't drive it much. plus, it's in the middle of a restore job, so it's not exactly user friendly.
i went to go run it the othe day, and would idle at 2k!
i don't think the tach is off. at 2k the sound is a dead give away.

Dewey316 · Posted: Fri Sep 21, 2007 11:21 am Post subject:

I would check IAC, make sure the throttle blades are closing, and also for vacuum leaks.

--John

pathology knight · Posted: Fri Sep 21, 2007 12:04 pm Post subject:

not to sound like a dummy...

what's an "IAC"?

i'm pretty sure the blades are closing. not sure why they wouldn't.
i've checked for leaks before and am pretty confident everything is good and tight.

Schultzy89GTA · Posted: Fri Sep 21, 2007 1:10 pm Post subject:

IAC = Idle Air Control valve. It is underneath your throttle body and has an electrical connector on it.

-Schultzy

pathology knight · Posted: Mon Sep 24, 2007 8:24 am Post subject:

that's not the one on the side (left side if looking at it) is it?
or is it directly underneath?

aaron_sK · Posted: Mon Sep 24, 2007 8:34 am Post subject:

The unit on the left side should be the throttle sensor. Look on the bottom left and you should see a large square four-prong plug, that will be the IAC.

pathology knight · Posted: Mon Sep 24, 2007 1:31 pm Post subject:

alright, i know what you're talking about now.

is that just a simple "get a new one and plug it in" sort of deal?

Schultzy89GTA · Posted: Mon Sep 24, 2007 5:07 pm Post subject:

You can actually try to clean it first. It is not uncommon to have a little carbon build up or debris interfere with the operation. I think there is a tech article on how to clean them on TGO.

Here is a pretty good thread: http://www.thirdgen.org/techboard/tech-general-engine/29360-iac-adjustment-not-working.html

-Schultzy

pathology knight · Posted: Tue Sep 25, 2007 2:34 pm Post subject:

i'll take a look at it and see if it looks dirty, but there's no way i'm going to trust myself to go through all that.
i guess if i have to, i can take it back to the shop. Crying or Very sad

Xophertony · Posted: Tue Sep 25, 2007 8:55 pm Post subject:

no no no... it is WAY too easy to cange for you to take it to the shoppe. i have literaly done this while my gas was pumping. you could borrow a wrench and do it in the parts store parking lot.

that said, i have a newer IAC and TPS, both adjusted properly and my car still does it. i think it is flapping between open and closed loop. i probably need to upgrade too a 3 wire o2 sensor.

pathology knight · Posted: Thu Sep 27, 2007 8:24 am Post subject:

so you think it may be an o2 sensor and not the IAC?