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Ignition is fairly straightforward, you can specify up to -22.5 degrees of retard in a map cell, or up to 168.75 of advance.
It all gets added up and then output 5 times per cycle.
There is a nasty "ignition overboost" function that has been patched out of the ECU - on a stock ECU ignition is randomly advanced and pulled back when hard knock is detected. Good on stock cal, when you have a lot of room left, very bad on a tuned car causing engine damage.

Timing maps

  • Ignition - Idle, closed throttle - used for fast-path idle control, it is read when the closed throttle switch is activated on the TPS. Set this map so, that you have some torque reserve, by setting the timing significantly later than MBT. Change the axis on the map so, that your ignition timing is what you would like to run at your target hot idle. Make ignition quickly ramp to MBT 200-300 RPM below it, and make it quickly ramp to a retarded state above it. Now you got closed loop ignition based idle control. This is used for the fast control, the ISV is the slow control, and will adjust in closed loop to your idle setpoint.
  • Ignition - Idle, warmup - used during the warmup stage, when engine is not yet hot. Tune it to follow your idle target map.
  • Ignition - P/T, no knock - Main ignition map.
  • Ignition - P/T, no knock, race fuel - Main ignition map when map switch active.
  • Ignition - P/T, knock level 1 - Gets triggered once knock retard exceeds a certain threshold, the bit is read from the I/O extender and is transferred to it from the fuel/ign chip.
  • Ignition - P/T, overrun - used when throttle is shut at high RPM. Tune it to be in-line with your fuel cut/resume.
  • Ignition - IAT correction - IAT based ignition timing correction.
  • Ignition - Load threshold for IAT correction - minimum LOAD for the IAT timing correction to be active
  • Ignition - CoolantxIAT correction/CAT heating - can be zeroed, used for cat heating at the expense of fuel efficiency.
  • Retard on positive load delta - This is how much to retard ignition on TPS delta/sharp throttle movements. It is instantaneous and lasts for one cycle. Useful because otherwise it is very easy to have knock on sharp throttle movements.


The Dwell map specifies the coil charge time. Below 500rpm there is some compensation for the way it is calculated, so the values are not exactly 100% meaningful. After 500 RPM - what you see is what you get.
In the map the dwell time is specified in crank degrees, but it has been converted to milliseconds with the help of TunerPro, as it is much easier to work with that way.