7.2 Fuel Settings 7 ADDITIONAL ITEMS: BEYOND BASIC FUEL AND IGNITION CONTROL
7.2.4 Fuel sensor settings (Flex)
The flex fuel system allows the use of E85 or other ethanol and petroleum blended fuel mixes to be used when a
special fuel composition. sensor is fitted. The support is specifically based around the use of a GM flex fuel sensor
which outputs a varying frequency signal depending on the fuel composition. This information can then be used
to add more fuel and advance timing. Ethanol blends need more fuel volume than unblended fuel and different
advance. The basic system uses a two-point system (low/high) and interpolates between the values. You can also
use flex fuel to create a blend curve, which is explained in the section on blend curves below.
• Flex fuel sensor - this enables or disables the Flex Fuel system
• Sensor port - where the sensor is connected. A GM flex fuel sensor typically has pin A as ground, B as 12
volt supply, and C to the MS3Pro Digital Switched In 1. Note that Digital Switched In 1 is currently the only
supported port.
• Temperature input - GM’s flex fuel sensors can output a fuel temperature signal based on their pulse width.
You can also specify a separate analog sensor, enabled under Generic Sensors.
• Spark / Fuel settings - These have separate low and high settings to define the range of sensor outputs.
– Frequency - Specifies the minimum and maximum frequencies the senor will send.
– Ethanol mix - Specifies the percentage ethanol at minimum and maximum frequency.
– Fuel multiplier - Ethanol requires more fuel. This is a percentage multiplier that scales how much fuel is
added.
– Timing addition - If not using a blended table, this simply adds a fixed amount of timing, interpolated
between the low and high points.
• Temp Sense - Allows setting up pulse width based fuel temperature output from a flex fuel sensor.
• Fallback fuel multiplier - If the sensor duty cycle goes out of range, the MS3 will apply this multiplier to the
fuel to avoid a lean condition.
• Fallback timing addition - How much to adjust the timing in the event of a sensor failure.
• Dual fuel mode - The ability to blend tables is enabled under the Table Switch / Dual Fuel screen.
AMP EFI MS3Pro manual version 1.202, firmware 1.5.0, 4/21/2017 Page 156
To Next Page
Loading...