Thanks for the tables and explanations
Quote:
Originally Posted by XfireZ51
I've attached a jpeg of 3 tables used for C/L operation. One shows the parameters for the ECM to consider if it was a HOT start, COLD Start or WARM start. Then there is an accompanying TIMER telling the ECM how long to wait before C/L based on the start-up temp. So anything under 29C will use 5 minutes as an example. However, in addition there is an O2 WINDOW.
So it could go out of C/L depending on whether its too rich or too lean with reference to the voltage being generated by the O2.
You also see a table for what the target AFR is when in O/L and that is referenced to CTS. So colder the coolant temp, the richer the mixture. The number in the table is how much additional fuel from the baseline. Changes in the baseline will affect this table then.
The O2 is the final word for C/L. Whatever the ECM is doing ends up as a signal from the O2. The feedback loop to the ECM causes it to modify the fueling accordingly. SA is being affected based on the RPM/MAP along w modifiers like DECEL, startup, CTS.
There is a table that defines for the ECM the amount of delay, based on airflow, before allowing the INT to change. Its an O2 INT Delay. This way the ECM correlates the effect of changes it has made w the results coming from the O2. Otherwise it would be out of sync and "chase its tail". In general, the use of headers and moving of the O2 further back has not demonstrated a need for changing the values in this table.
Most tuners will resort to O/L when larger cams are introduced into the equation. All "LEARN" happens in C/L. However, LEARN is not always ON with C/L. Several other parameters define when LEARN is active. If LEARN is not active, the ECM uses whatever fuel trims have been stored for those cells. The overall goal is to get the VE tables to be as close to optimum as possible requiring little intervention by the ECM.
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The values in these tables are not necessarily stock.
