I see multiple charts that use this. (0-16 by increments of 2)I'm new and stumped a bit. What do the numbers realate to?
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I see multiple charts that use this. (0-16 by increments of 2)I'm new and stumped a bit. What do the numbers realate to?
Anyone? Keith, can ya help me out? Maybe it's a dumb question, I dunno!
The VCM takes the airflow range and divides it up into smaller chunks known as "modes"
Other parts of the closed loop code look to see what mode it's in to select range values from the lookup tables.
The modes are to be considered airlfow range steps.
Ken
So then what mode goes with what? Mode 0 covers? mode 2 covers? etc? I'd like to learn this software completly.
Ken? Keith? Anyone?
The Airflow Mode corresponds with the MAF table airflow (g/sec) and is used to determine o2 sensor cross points, gain, and time values for closed loop fuel correction. You would only need to adjust this if your o2 sensor values were "railing" all the time because of large injectors or incorrect time constants / switching voltages in the Proportional or Integral tables for your particular combination.
In other words, you can bias the rich/lean switch points (slightly, as an o2 sensor has a VERY narrow bandwidth, natuarlly) to either give you a *slightly* richer or leaner AFR at that particular MAF range.
GM systems work on a PID loop: Proportional (gain) Integral (time) and a pseudo Deriviative value (o2 Error)
The Proportional value is the rate you go from point A (filtered o2 mVdc) to point B (451 mVdc).
The Integral is how much filter time you need to determine point A reasonably
The pseudo Derivative is the instantaneous o2 mVdc value from the sensor.
HTH
EC
TTT looking for more info on this subject...any insights please post up.
Quote:
Originally Posted by WS6snake-eater
More info on which subject?
The airflow mode tabe re-maps the engine Mass Airflow range to fit it on the smaller tables used for closed loop.
The values on that table (0-16) correspond to the axis on several other tables (i.e. XXX vs Airflow Mode).
Ken