My six-cylinder 2008 Acura TL specifies "premium" fuel. My wife often fills it with "regular" (i.e., 87 octane).
As I understand it, under certain operating conditions and loads, the lower-octane fuel might begin to knock. The engine is equipped with knock sensors, and the presence of knock will be noted in one or more OBD parameters. Question 1: What OBD parameters would indicate knocking (and via what values/units)?
In response to knock, the ECU will retard the spark timing. The degree of spark delay will also be noted in OBD. Question 2: Which parameters and values would indicate the timing and other changes implemented to avoid knocking?
I want to analyze the effects of using low-octane fuel over the course of a tank of gas. Question 3: What is the most economical way of collecting and storing the data involved in the first two questions over an extended period? E.g., are there plug-in OBD loggers with large memory buffers? Or is there PC software designed to interface with the OBD for this sort of analysis?