Proportional fuel thoughts
Copied literally from the help menu in the editor:
Quote:
These two tables affect the % fuel needed for proper closed loop response and start the STFT process
Closed Loop Proportional Base vs. Airflow Mode: This table returns the base proportional % fuel change. Proportional base rate table is the primary amount of fuel needed to drive the closed loop fuel control into oscillation. Proportional fuel acts like an on/off switch to keep the fuel moving around the current O2 Rich/Lean vs. Mode table set point. The values on the Proportional Table add or subtract to the base fuel rate depending on the previous fuel condition (i.e. if rich then switch lean, if lean the switch rich). The amount of fuel to add or subtract increases with the airflow mode and should be based on injector size and % fuel switching needed.
Closed Loop Proportional Gain vs. O2 Error: This table returns a multiplier value for the increase/decrease of the base rate table. A multiplier value of 1.000 will have no effect on the proportional base rate. If the difference between the current O2 reading and its desired value from table O2 Rich/Lean vs Mode (the current Fast O2 error) is large the VCM will need to change the proportional fuel a lot. If the error is small, it should change it only a little to continue oscillation without undershoot or overshoot. Undershooting will cause the Closed loop fuel to become sluggish or miss the current O2 Rich/Lean vs. Mode table set point. Overshooting with cause the engine to vary excessively in RPM.
I have my tune pretty much spot on. Its an LS7 with a big cam (Duration @ .050” is 249 INT 261 EXh Lift .650”/.650” LSA 112) and I am running CL with a maf and a 2002 F Body OS.
The last little bit of fine tuning I am working on is that sometimes under low throttle conditions I can feel the proportional fuel doing its thing.
You can also hear a slight change in the exhaust note when this happens.
Anybody have experience with this subject that would like to share?
Is it possible to regain near stock fueling conditions?
