The SDSEFI.COM EFI / EI system is different from traditional magneto driven systems in that it uses dual electric fuel pumps to provide fuel to the engine rather than an engine driven mechanical fuel pump plus an an electric “boost” pump used during critical phases of flight (take-off / landing / emergencies).

The dual electric fuel pumps are used by the SDS electronic fuel iunjection (EFI) system as they provide the higher fuel pressures required by the EFI.

In my case I wanted the ability to select either fuel pump # 1 or fuel pump # 2 as being active using a switch on the panel. I also wanted the non-active pump to be selectable using a push button located on my Infinity control stick. To accomplish this I used a three position switch (#1 – off – # 2). The non selected fuel pump then becomes the “aux” fuel pump activated using the button located on the control stick.

I also added an additional circuit that automatically turns the “aux” fuel pump on whenever the G3X system displays a Master Warning message. For example if my fuel pressure falls below normal (into the “warning” range, the aux fuel is automatically energized. This additional circuit is the PCB Module shown in the dotted line rectangle.