Fast Idle; Intake Air Temp Sensor
Thread Starter
Intermediate
Joined: Mar 2005
Posts: 34
Likes: 0
From: Island Heights NJ
Fast Idle; Intake Air Temp Sensor
Could a faulty Intake Air Temp Sensor cause a fast idle?
While changing the heater, throttle body, and heater hoses I cracked the housing of what I think is the Intake Air Temp (IAT) Sensor. This is grey with 4 female prongs on the sensor end and four metal pins at the male end, located at the passenger side bottom of the throttle body, next to the hose from the throttle body to the heater hose T. It cracked while trying to get to that hose's spring loaded clamp.
Once I replaced the antifreeze and put everything back together, the car ran fine. Except, the idle speed is 1200rpm vs. the normal 600-700rpm range. The sensor fits back into the housing, but I wonder if cracking the plastic clips on the housing is effecting the idle speed?
The check enging light has not come on. Would there be codes stored if I plugged into the Drivers Info Computer? How is that done? I am hoping a trouble code for the sensor, or for whatever is causing the fast idle, will show.
If the problem is the AIT sensor, I have seen articles about relocating this AIT from the throttle body to the intake tube behind the air filter. Has anybody done this, and what is the result?
While changing the heater, throttle body, and heater hoses I cracked the housing of what I think is the Intake Air Temp (IAT) Sensor. This is grey with 4 female prongs on the sensor end and four metal pins at the male end, located at the passenger side bottom of the throttle body, next to the hose from the throttle body to the heater hose T. It cracked while trying to get to that hose's spring loaded clamp.
Once I replaced the antifreeze and put everything back together, the car ran fine. Except, the idle speed is 1200rpm vs. the normal 600-700rpm range. The sensor fits back into the housing, but I wonder if cracking the plastic clips on the housing is effecting the idle speed?
The check enging light has not come on. Would there be codes stored if I plugged into the Drivers Info Computer? How is that done? I am hoping a trouble code for the sensor, or for whatever is causing the fast idle, will show.
If the problem is the AIT sensor, I have seen articles about relocating this AIT from the throttle body to the intake tube behind the air filter. Has anybody done this, and what is the result?
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
First... DO NOT ADJUST the idle with the throttle stop screw.
The part you described is the 'IAC'. That's the Idle Air Control.
It controls the idle air and therebyu the idle speed.
It may still work but you'll need to perform a procedure called the 'Minimum Air Adjustment'.
I can't remember the procedure but it's simple and quick to do.
Search for 'Minimum Air' adjustmemt procedure here and you'll find a description of the procedure.
Takes about 2 minutes to do.
THen...... if it still won't idle correctly you'll need to replace the IAC valve and then go thru the adjustment procedure.
Not to worry, the IAC is not an expensive part. Get one at most any auto parts store.
Good luck with it.
The part you described is the 'IAC'. That's the Idle Air Control.
It controls the idle air and therebyu the idle speed.
It may still work but you'll need to perform a procedure called the 'Minimum Air Adjustment'.
I can't remember the procedure but it's simple and quick to do.
Search for 'Minimum Air' adjustmemt procedure here and you'll find a description of the procedure.
Takes about 2 minutes to do.
THen...... if it still won't idle correctly you'll need to replace the IAC valve and then go thru the adjustment procedure.
Not to worry, the IAC is not an expensive part. Get one at most any auto parts store.
Good luck with it.
Last edited by VetNutJim; Feb 18, 2007 at 01:00 PM.
Thread Starter
Intermediate
Joined: Mar 2005
Posts: 34
Likes: 0
From: Island Heights NJ
Thanks for the reply. I searched "Minimum Air Adjustemnt" and read through the threads. There was talk of the ECM "learning" the idle speed, and on a hunch, I started the engine since yesterday. Low and behold, the idle is normal. I can't explain it. When I first started the engine yesterday after adding the coolant, the air cleaner plenum was off, with the sensors attaching to it disconnected. (The bleed screws on the water pump are easier to access with the plenum off.) I wonder if that may have changed the idle?
