Hi,

In the abridged excel (rename to .xls) data log I've attached is a "mash the gas" type run up a freeway on ramp where I got knock counts / retard. The run involves a 2-1 downshift during the area where knock counts occured.

I noticed that during the time I'm mashing the gas, from closed throttle + 1.5 seconds (15 samples), the wideband AFR shows pretty lean considering the load values (LV8) involved. I understand that there is always some lean spike on a rapid throttle transition since the air movement occurs ahead of the ECM's ability to react to it, but should be this long (1.5 seconds)?

What is a reasonable lean spike duration?

Is it reasonable to conclude that 1.5 seconds of lean combined with high load caused the knock counts, rather than the timing being used once full PE is underway?



Thanks!