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View Full Version : Changing AFR to 14.7?



Black'Rado
February 11th, 2011, 03:11 PM
Ok in my current tune i have stoich AFR set to 14.12 to adjust for up to 10% ethanol. I am getting horrible gas millage even just driving like a grampa. Also when idling the exhaust smells like its super rich, even though i have no cats i dont think it should be quite this strong smelling.

Do yall think i should just lean it out to 14.7 or is there something else i could be missing.

tune attached

WeathermanShawn
February 11th, 2011, 05:05 PM
As always a log would tell a lot.

Its somewhat of a misconception that in closed-loop (which you are) you can control the true lamda of a fuel. Regardless of what you enter in B3601 the vehicle will burn at the stoich of the fuel type. So, if its Ethanol you could change that number to 'leaner' and it will have no real effect. Your Trims would just compensate regardless.

Ethanol and cold weather just dramatically reduce gas mileage. It might be interesting to see how your vehicle is Trimming..thats about the only other factor I can see. Personally I think a lot of it is just the cold weather. That does more to alter Injector flow than anything.

At least thats my thoughts. Good luck..