Originally Posted by TimBle

It does not need an O2 sensor for several reasons:
-the engine design parameter is not hinged on stiochiometric AFR. That is a requirementonly to allow emissions controls devices to function as calibrated. It is NOT a necessary function for this system.
- O2 sensors cannot handle high percentage of contaminant in the fuel. It will plug up and fail ver quickly with 2stroke oil in the mix.
- An engine's ECU can determine load, and fuel demand by monitoring throttle position against rpm to determine load. Couple to a mass flow sensor (air intake sensor as described by HH) the ECI algorithm will determine correct fuel metering and can be designed to erroe correct and either slightly overfuel or underfuel (non prefered).

This engine is not flying long duration missions carrying relatively heavy payloads to the airframe. It is a toy airplane engine designed to take tuning out of the hands of Joe Soap.

Lastly, comparison with methanol fuel injection is comparing apples and oranges. Methanol fueled engines have high oil percentage and the oil presents problems to fuel metering