Quote:
Originally Posted by rice_classic
Jedibow: in asking if all OBDII ecu's do that, I wasn't referring to ignition management via knock control. That I knew. I was referring to auto-advancing to take advantage of higher octane than what the car was designed for. My 1996 Ford Econoline Van designed to run on 85-87 octane doesn't seem to "figure it out" when I've put in 93 octane and I have a sneaking suspicion that most OBD2 ECU's are not "adaptive" like the Camry 2GR. The discussion wasn't based around retarding once detecting knock, it was based around automatic detection of higher octane for specific design and subsequently automatically altering ignition timing.
All OBDII ecu's retard timing when knock is detected. Check
All OBDII ecu's on cars designed for 87 octane automatically detect and advance timing when higher octane is introduced than what the car was designed to run on? I don't think that's true.
But..  |
Sorry, only certain ECU's are proactive to determine what ignition timing and fuel tables to run, namely Toyota, Subaru, and Volkswagen mostly. Most ECU's are reactive, and only retard ignition as they see knock, so the maximum timing it will run will be the value on the timing map (they cannot exceed these values) unless effected by a multiplier table such as barometric pressure, or tempurature adjustment tables.
I would also like to state that even though subaru ECU's are proactive, there is also a maximum value that the ECU would apply for timing, and no it would not take full advantage of using 100 octane fuel.
I'm sorry I hope that clears things up a bit, I've had a lot going on lately and have been in a bad mood. Again I'm sorry.