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Optional Fuel Flow Output to Engine Monitors
SDS EM-5 ECUs with V26.1 or higher software have the capability to output a fuel pulse signal similar
to electro/mechanical flow meters. This capability is also activated through a discrete PIN number for
each individual software burn# once the option is paid for.
Output to your engine monitor is via the brown wire on pin 2 of the injector drive harness plug.
In SETUP MODE, (see setup mode section), scroll right with the > button until you have this windows
displayed:
SETUP FUEL PULSE OUT. This calibrates the output to the engine monitor to fine tune the fuel flow
and totalizer amounts depending on injector flow rate. The normal range of values is about 150 to
450. Maximum is 655. A higher number here = a lower displayed fuel flow. Use the +/- 1 button to
change the value.
We can provide you with an approximate value to enter for your injector type. Fine tuning and
calibration of this value is up to the user. Never rely on the fuel flow readings or totalizer
amount until calibration tests verify the accuracy of the displayed information! For Dynon
engine monitors, we recommend a value of 29,000. You can tweak either the SDS or Dynon value to
calibrate.
To calibrate, on aircraft with two fuel tanks, we recommend filling the tanks and doing all ground
running, takeoff and climb on one tank. Once you get to cruise altitude and set cruise power, switch
tanks and fly for one hour, preferably at the same power setting, note the displayed FF. Switch to the
other tank at the one hour mark and use this tank for the rest of the flight and ground running prior to
shutdown. Refill the cruise tank first and note the amount taken. See how well this compares with the
indicated FF in cruise. Fill the other tank and see how the total amount taken agrees with the totalizer
amount. Tweak as required several times until you’re satisfied with the accuracy of the displayed
amounts.
Scroll right one more place to see:
SETUP FUEL PULSE INJ LAG. This calibrates the ECU for injector latency or lag time which is the
amount of time it takes for the injector to open after current is applied to it. This number is usually
between about 1000 and 2000. We can provide you with the number to enter for the 2 types of
injectors we offer.
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