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Wide Band Fuel Mixture Display

Wide Band Fuel Mixture Display

An introduction to the Wideband Fuel Mixture Display (FMD). This document describes how the 5300/5301 display works with the DIY-WB unit.

The three regions of operation are shown at right. A normal operating value (of 14.7 in this case) is shown as three digits. A rich condition is shown as 10. followed by an equals or less than symbol (=<). A lean condition is shown as 25. followed by a greater than or equals symbol (>=). Note: display is operating in dot mode.

Other software changes are to:

  • Make more efficient use of table space to allow the addition of the Lambda display mode.
  • Redesign for more modularity for possible future upgrades.
  • Version and mode information displayed on startup.
  • Better calibration capability for DIY-WB output range.

The major changes have to do with how the dot and bar mode display intervals have been altered.


Dot mode displays 48 unique LED configurations with a difference of 0.2 AFR between steps, from 10.0 to 19.6 AFR. Either one single LED is fully lit, or two LEDs are lit with a varying intensity, giving the impression the LEDs move slowly upwards as the display shows a richer mixture. The single centre LED is lit for AFRs between 14.6 and 14.7.

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