How does IAC effective area work?

[odd boy]

Guys,

Any one knows who {B4403}IAC effective area works?

[SSpdDmon]

It translates an airflow value into # of steps IIRC. Essentially, it's defining the airflow characteristics of the IAC valve. It's rare for this table to need adjustment.

[odd boy]

what if a cam is added, and what does step mean?

[5.7ute]

Doesnt matter if a cam is added. It is a measurement of the effective area under the iac valve.
As for step that is how the iac valve operates. It is a stepper motor that moves by small increments in or out depending on what the pcm commands. Each step open will increase the amount of air that can bypass around the throttle blade. Since the pintle on the stepper motor is rounded & the seat is flat, greater control of the airflow is achieved at a lower step count. This is why at warm idle you should be shooting for between 40 & 80 steps. Once the pintle has moved beyond about 120 steps it has a very minimal effect on airflow per step, so it will need to make large movements to control airflow. This will make it too slow & inconsistant to correct for swings in idle speed.

[SSpdDmon]

Doesnt matter if a cam is added. It is a measurement of the effective area under the iac valve.
As for step that is how the iac valve operates. It is a stepper motor that moves by small increments in or out depending on what the pcm commands. Each step open will increase the amount of air that can bypass around the throttle blade. Since the pintle on the stepper motor is rounded & the seat is flat, greater control of the airflow is achieved at a lower step count. This is why at warm idle you should be shooting for between 40 & 80 steps. Once the pintle has moved beyond about 120 steps it has a very minimal effect on airflow per step, so it will need to make large movements to control airflow. This will make it too slow & inconsistant to correct for swings in idle speed.

[odd boy]

for example:

when 120 mm^2 = 310, it needs to do 310 steps to open fully. Please correct me if I am wrong