Setting up stepper motor (iacv)

I have a fl 1 1.8.
It has been abused by the previous owners. The list of bodges is impressive including unable to find knocking noise from front suspension, which was a loose subframe bolt and one MISSING !!!!.
Anyway i need help setting the iacv.
In order to get the correct amount of steps i have to unscrew the throttle plate stop fully ( metal type) which then means it is sticking shut making it an interesting drive when pulling away.
I have checked for airleaks but can't find any.
Any help would be appreciated. Ta

The IACV is self calibrating, which is why it cycles back and forth at engine shutdown.
On shutdown, the IACV fully closes, then cycles out to the correct position for starting next time.
They can go sticky, which causes interesting issues. Sometimes they can be cleaned, but sometimes only a replacement will work.

My iacv is new that's why i need to set the base setting. It the throttle plate that is sticking

dustybus said:

My iacv is new that's why i need to set the base setting. It the throttle plate that is sticking

Click to expand...

The throttle butterfly isn't connected to the IACV.

The IACV ( Idle Air Control Valve) an electro-mechanical device that allows air to bypass the throttle butterfly.

The throttle butterfly is supposed to close almost tight under spring pressure, and is opened by the throttle cable pulling on the throttle cam. If it's not closing freely, it needs freeing off, or replacing.
When the throttle butterfly is closed (assuming the cable has enough slack and its not sticking), then the IACV opens up, so the engine engine has enough air to idle at the correct speed.
The ECU also "tweeks" the ignition timing while idling, using slight timing changes to make small in engine speed changes, which wouldn't be possible using the IACV alone.

There isn't a base setting for the IACV, as it's self calibrating.

However if the throttle butterfly isn't closing, the IACV won't be able to calibrate itself, as it's not controlling the engine speed, the stuck throttle butterfly is.

In order to set the correct steps the throttle stop is used to adjust the airflow. According to data from s/p acr4

dustybus said:

In order to set the correct steps the throttle stop is used to adjust the airflow. According to data from s/p acr4

Click to expand...

The throttle butterfly has a factory set adjuster, which is set to allow a tiny amount of air through the throttle body.
The engine wouldn't run with the small amount of air that this small preset opening provides.
So to supplement this, the IACV indexes open to run the engine at an approximate speed, the ignition timing being tweeked to get the idle to within + or - 50 RPM of the target speed.

I'm not aware of any additional measures to manually calibrate the IACV, as position calculations are normally done on the fly by the ECU.

There is a calibration for the throttle position sensor on the TB, but that requires T4.
If other calibrations are needed, then presumably T4 would handle those too.
T4 is dedicated LR diagnostic equipment, just in case you're not aware.

Fixed it.
In between adjustments i was not giving it a big enough rev.
All set as per spec now and no sticky throttle.