Flex Fuel🔗

This module determines flex fuel composition in vehicles that use a flex fuel composition sensor to determine the ethanol percentage used in the fuel. This percentage impacts multiple calculations, including those for fueling and ignition among others.

Having a correct value for flex fuel composition helps prevent engine damage or performance issues that could arise from using an incorrect value for the ethanol-gasoline blend. Different ethanol content levels require different air-fuel ratios and ignition timing to operate optimally.

Since fuel composition sensor readings may have sudden spikes during transient conditions, the fuel composition reported by this module will be locked at the last reported value when all three of the following all true:

Cylinder airmass is above Flex Fuel Composition Lock Cylinder Airmass
Engine speed is above Flex Fuel Composition Engine Speed
hrottle position is above Flex Fuel Composition Lock Throttle Position

Flex fuel composition will be unlocked when these conditions are no longer met.