Quote Originally Posted by Kyne View Post
You do realize all O2 sensors are actually lambda sensors not AFR sensors right? It senses lambda then multiplies it by an assumed stoichometry factory (14.68 for pure gas, 14.57 for indolene clear, 9.8 for e85) to come up with this imaginary AFR. So if your commanded lambda in your "lean burn tune" is 1 then it isn't lean burn. It has to command a lambda of >1.0 to be lean burn. The problem lies in your basic understanding of tuning. I was trying to help but I feel like I'm being fought the whole way.

For those who care the definition on closed loop is to keep the fuel ratio at stoich, so you cannot in any car with a narrow band have it lean burn and in closed loop. It has to be in open loop or if it has a wideband for a stock o2 (some newer cars) because the computer will correct it to stoich or lambda 1.00 which is 14.68 afr on pure gas.

And you can tell if you are in closed loop if you have fuel trims or your o2 readings are oscillating.
Ah, so you're saying my car did the impossible then.