A Flex Fuel Composition Sensor is used to monitor the ethanol content as well as the temperature of the fuel. This can be used with your ECU for Flex Fuel tuning to suit a varying blend of ethanol in the fuel, for datalogging, and for Engine Protection purposes. The Haltech Flex Fuel Composition Sensor uses a digital frequency to report ethanol percentage to the Elite ECU, with fuel temperature as the period (pulse width) of the signal. The sensors are generally powered with switched 12v, their signal wired to an SPI input and the ground provided by the chassis.

Flex Fuel Composition / Temperature Sensor Configuration

On this node, the Flex Fuel Composition/Temperature sensor input can be selected. This can only be a digital frequency input due to the nature of the combined composition/temperature values broadcast by the sensor. Choose an available SPI input with the Edge Select to Rising, Sensor Type to Hall Effect and Pull Up to Enabled.

SPI Glitch Filter

This table sets the amount of time in microseconds that the signal pulse must remain in a transitioned state in order for the signal to be accepted as valid. 

Any pulse shorter than this time will be considered a glitch on the signal and rejected by the ECU.

Fuel Temperature

See the Fuel Temperature help node. The wiring portion will be locked to share the signal from the primary Composition Sensor input.

See the Flex Fuel Composition help node. The wiring portion will be locked to share the signal from the primary Composition Sensor input.