Resetting Base Idle Using WDS
#21
To a certain extent yes. I'm familiar with Ford ECU's, where there is a time component that it writes a biasing table that is overlaid over the main map. The biasing table is what applies a correction factor to the LTFT, such that over time if there is a persistent STFT in one direction, either rich or lean due to that particular engine, the biasing table will be written such that eventually the ECU will adapt and bring the STFT to zero.
So factory fuel map + biasing table = new map, such that the resultant STFT is minimal. Obviously the biasing table is written for a particular ECU and engine combination.
When you're swapping the ECU's, you're going to have to rewrite that biasing table, and that takes time; now that the STFT are pinned the other direction. That's why I was asking if there is a factory reset option that will set the biasing table to zero.
The biasing table is slow to write and slow to change on purpose, as it's a general trend modifier, not a transient modifier. So driving for a day won't change it much, you'll need to put quite a few miles on it to change it in any substantial way.
Note that I'm calling it a biasing table, I have no idea what Jaguar might call it, so don't necessarily go looking for that particular term.
So factory fuel map + biasing table = new map, such that the resultant STFT is minimal. Obviously the biasing table is written for a particular ECU and engine combination.
When you're swapping the ECU's, you're going to have to rewrite that biasing table, and that takes time; now that the STFT are pinned the other direction. That's why I was asking if there is a factory reset option that will set the biasing table to zero.
The biasing table is slow to write and slow to change on purpose, as it's a general trend modifier, not a transient modifier. So driving for a day won't change it much, you'll need to put quite a few miles on it to change it in any substantial way.
Note that I'm calling it a biasing table, I have no idea what Jaguar might call it, so don't necessarily go looking for that particular term.
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