After studying the available E40 idle calibrations, I conclude that the torque reserve needs to be at least 13* {B1530} below MBT with -11* over speed reduction {B5131}.
The calculated torque is based on throttle angle vs RPM {B2513}, there isn't an optimal timing calibration like the LS1.
The extra load from AC auxiliary is compensated by adding airflow to the minimum idle airflow calibration {B1829}, opening the throttle further, there is a delay timer between switching on and AC on to allow rpm to increase accordingly. There is no viewable calibration for power steering load.
{B1829} can be considered to be the same as a stop screw on a carburettor, the minimum TB angle.
An idle tune strategy might be if your have changed cam and heads (or improve fuel consumption over stock),
Determine idle MBT and airflow, log airflow closed loop and trims to correct the airflow, MAP, fuel IPW and or Litres per hour and electronic throttle position, in efilive you can create a custom calc pid to increase the resolution for the TB (8/10ths per 1%), while increasing idle spark * incrementally until minimum airflow/MAP/IPW/TB% / diminishing returns.
Create a table to display airflow per 0.5* timing advance
Decide on the optimal idle timing value at least 13* back from MBT, set the minimum idle airflow to the idle timing value +13* in {B1829}. If more torque is required to maintain idle rpm, idle spark increases, the TB angle needs to decrease a little (more torque from less airflow), if minimum idle airflow is too high, TB can not close further so rpm will increase until it finds equilibrium state.
Test these settings with AC on /off, turn steering wheel to full lock and check for stall.
If it stalls, greater torque reserve is required, decrease idle timing repeat above.
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Originally Posted by joecar
