IAC Valve Questions
Thread Starter
Joined: Aug 2006
Posts: 9,091
Likes: 26
From: At The Bar
IAC Valve Questions
Hello all, happy New Year!
So here's my tail of woe. Three nights ago when pulling my MY01 out of the garage the CEL popped and it was idling wierd (oscillating almost). Stopped at the local gas station to see if they could pull the code and, much to my chagrin, they could not. After filling up I started the car and it ran just fine, a distinct change from the pre-fill-up performance. Took it on a 20 minute drive and it behaved totally normally. Dropped by a friend's house, checked the board and found that the problem sounded like an IAC valve. Though I know that I'll be given some s*** for this I reset the ECU and performed the Idle Learn procedure as it is outlined here. No CEL and normal performance. Hooray, right?
The car ran normally until early this morning, coming home from a New Years party. Started it up, CEL popped again and the problem was back in full force. The idle oscillates in the 2300-2600 range fairly quickly and, when clutching to shift, the revs drop much more quickly than normal. Came home, checked the board and am now totally sure that the IAC is the culprit. Fast-forward to this morning.
Much to the chagrin of my hung-over neighbors I pulled the car out of the garage bright and early this morning to go over things in the daylight. Some of the advice thats given here involves "bump-maintenence" of the IAC valve and MAP sensor. Gave both items a bump to no avail. Tried resetting the ECU again (I know, I'm sorry!) and that didn't fix the problem; the CEL popped right away and when I went back outside after letting the car idle for 10 mins the RPMS were oscillating something fierce. Feeling both furious and helpless I retired inside to the Monk marathon on USA and to search the forums some more.
After calling my dealer only to find that, though their sales department is open, the service guys get the day off, I went back outside, kicked a tire, and started it up. Totally normal performance! Took it for a short spin and everything's normal, though the CEL is still on. What gives?
My questions are as follows:
--Members here on the board diagnose this as a non-serious problem and driving the car is fine even when its behaving badly; when driving with the active problem it feels like the motor is going to rock itself off the mounts. Is this really safe?
--When I bought the car I got the ASE extended used car warranty; would this part be covered under this warranty?
--If it's not warrantied, how tough is this part to replace on my own?
--Is the intermittancy of the problem indicative of something that I'm doing wrong? Is there something that I can do short of replacing the part that will fix the problem?
I thank you all in advance for your help, I plan on taking the car to Auto Zone to pull the code tomorrow but would like to have some input sooner rather than later. Hope you're all having a great National Hangover Day!
--Chazz
So here's my tail of woe. Three nights ago when pulling my MY01 out of the garage the CEL popped and it was idling wierd (oscillating almost). Stopped at the local gas station to see if they could pull the code and, much to my chagrin, they could not. After filling up I started the car and it ran just fine, a distinct change from the pre-fill-up performance. Took it on a 20 minute drive and it behaved totally normally. Dropped by a friend's house, checked the board and found that the problem sounded like an IAC valve. Though I know that I'll be given some s*** for this I reset the ECU and performed the Idle Learn procedure as it is outlined here. No CEL and normal performance. Hooray, right?
The car ran normally until early this morning, coming home from a New Years party. Started it up, CEL popped again and the problem was back in full force. The idle oscillates in the 2300-2600 range fairly quickly and, when clutching to shift, the revs drop much more quickly than normal. Came home, checked the board and am now totally sure that the IAC is the culprit. Fast-forward to this morning.
Much to the chagrin of my hung-over neighbors I pulled the car out of the garage bright and early this morning to go over things in the daylight. Some of the advice thats given here involves "bump-maintenence" of the IAC valve and MAP sensor. Gave both items a bump to no avail. Tried resetting the ECU again (I know, I'm sorry!) and that didn't fix the problem; the CEL popped right away and when I went back outside after letting the car idle for 10 mins the RPMS were oscillating something fierce. Feeling both furious and helpless I retired inside to the Monk marathon on USA and to search the forums some more.
After calling my dealer only to find that, though their sales department is open, the service guys get the day off, I went back outside, kicked a tire, and started it up. Totally normal performance! Took it for a short spin and everything's normal, though the CEL is still on. What gives?
My questions are as follows:
--Members here on the board diagnose this as a non-serious problem and driving the car is fine even when its behaving badly; when driving with the active problem it feels like the motor is going to rock itself off the mounts. Is this really safe?
--When I bought the car I got the ASE extended used car warranty; would this part be covered under this warranty?
--If it's not warrantied, how tough is this part to replace on my own?
--Is the intermittancy of the problem indicative of something that I'm doing wrong? Is there something that I can do short of replacing the part that will fix the problem?
I thank you all in advance for your help, I plan on taking the car to Auto Zone to pull the code tomorrow but would like to have some input sooner rather than later. Hope you're all having a great National Hangover Day!
--Chazz
Registered User
Joined: Mar 2006
Posts: 3,615
Likes: 0
From: 951
If it is the IACV than it is pretty simple to replace, you might get a little coolant on your hands but it isnt anything hard,
have you tried disconnecting and reconnecting the plug at the back of the IAC?
have you tried disconnecting and reconnecting the plug at the back of the IAC?
Former Moderator
Joined: Jul 2001
Posts: 8,821
Likes: 5
From: Jacksonville, FL
The IAC may just need cleaning. Just a couple screws hold it in place and the coolant lines. There is a thin rubber gasket (more like an o-ring) that you need to be careful with, but otherwise use some Seafoam or other carb/throttle body cleaner in the chamber on the inside of the module.
Moderator
Joined: Jul 2002
Posts: 22,386
Likes: 1,838
From: Long Island, New York
There's a release button hidden on the UNDERSIDE of the IAC valve, under the rubber. You don't need to pull the rubber back, just feel for the button under the rubber.
Oscilating throttle at idle is definitely a stuck IAC valve.
Oscilating throttle at idle is definitely a stuck IAC valve.
Thread Starter
Joined: Aug 2006
Posts: 9,091
Likes: 26
From: At The Bar
Pulled the IAC off, cleaned the crap out, put it back on, runs as well as it ever did.
The dealer was going to charge me $180.00 for the part and $100.00 for labor. I bought a $2.99 can or carb cleaner. This forum just saved me $277.01. Un-real. Thanks so much for your help all, I can't say that enough.
--Chazz
The dealer was going to charge me $180.00 for the part and $100.00 for labor. I bought a $2.99 can or carb cleaner. This forum just saved me $277.01. Un-real. Thanks so much for your help all, I can't say that enough.
--Chazz
