[teoman]

Not really fooling it, it is doing its job of creating the optimum mixture (that engineers specified) and it it doing its job relatively well. No need to adjust the carburator when at altitude etc...



You could fool the ecu with an o2 sensor (wideband) and make it believe that it is burning more fuel than it actually is, this way you can get it to lean out the mixture.

And some ecus are designed for "lean burn", they inject less fuel in certain conditions. Lean burn can have ignition problems and emissions problems if the car is not designed for it.