Idle Spark Scatter is a useful strategy to help maintain a steady idle by adjusting the ignition angle in real time to vary the engines torque. We will be using the Idle Tab in a default layout.


You will need to set your Idle Conditions (marked blue in the image below) such that the ECU knows when it should be in idle mode. You will need a correctly calibrated throttle position sensor for this to function.


It will activate whenever the engine is in the Normal Idle mode (as shown by the Idle Status DRO, marked green), and will then look at the target RPM table (pink) for idle , and adjust the ignition advance by looking up the current "error" (the difference in the engines current RPM from the Target RPM, shown with the yellow border below) in idle speed and applying the modification to the final ignition advance based on the Idle Ign. Av. Spark Scatter Table. (red).


You can see below in the spark scatter table (bordered in red) as we go over the target RPM, we take off some advance, up to around 10 degrees, then as we approach target RPM, we no longer modify the advance, and finally ikf the engine starts to slow below the target RPM, we add around 10 degrees advance at a -300 RPM error. Tuning will find the best results as needed.