Hello Shark,
Start with P=I=D=0, and adjust the reference curve only. If you want to perform tests without running the engine follow procedure below:
1) make sure the valve has power applied to it.
2) adjust PWM frequency to around 100Hz, set min duty to 0% and max duty to 100%
3) use test function in VemsTune, its available under Tools->Iac lock.
4) in Iac lock tool make sure you are getting a larger opening (more air) when you enter a higher number, if the control direction is reversed, invert the output channel. Take care some valves have a limp home position in the beginning before the actual larger opening comes into view, if so make note of the required duty cycle to get passed the limp-home section (on the iac duty cycle gauge) and enter this into the min duty (in iac hardware settings).
The following adjustments require running engine:
5) if the steps above are verified, you can reconnect the iac valve and start the engine, now adjust the iac reference curve as the engine warms up. Aim for rpm 200 rpm above the requirested target for that coolant temperature.
6) repeat the cycle as many times as needed to get the full curve filled, let engine cool in between adjustments.
7) if this is completed you can think about reenabling PID control, but only if engine runs and starts normally now. Suggested starting values for PID can safely be used from defaultfirmwareconfigs/config_1.2.23.vemcfg included in your VT install dir, make sure to import only these settings using the IMPORT button in the idle control PID settings dialog.
Best regards, Dave