SDS Fuel Flow to G3X

[jwyatt]

I'm flushing the final quirks out of a new G3X install, and the last one is an inop fuel flow indication. I have the SDS EM-5 ECU, which has been happily supplying fuel flow to my old AFS4500 panel for years...but the G3X is reading 0gph.

Can anyone who has successfully connected the SDS EM-5 (or I assume EM-6 is the same) fuel flow pulse output to the GEA24, confirm my configuration is correct?
- EM-5 pin 2 "brown wire" -> GEA24 J243 pin 23 "Fuel Flow" (I have confirmed continuity of this wire from pin to pin).
- No other fuel flow connections (gnd, +12V, etc)
- GEA24 Fuel Flow input active. I have tried setting it as a "Floscan", an "FT-60", and "Custom 0-5000Hz", and K-factors of 304, 3040, and 30400 (my former setting was noted as "304").

My EM-5 also had a software update to support the newer style programmer, so it's possible the issue lies there, but I unfortunately don't have an ocilloscope to test the pulse output is active.

 

[Pdp7427]

I'm flushing the final quirks out of a new G3X install, and the last one is an inop fuel flow indication. I have the SDS EM-5 ECU, which has been happily supplying fuel flow to my old AFS4500 panel for years...but the G3X is reading 0gph.

Can anyone who has successfully connected the SDS EM-5 (or I assume EM-6 is the same) fuel flow pulse output to the GEA24, confirm my configuration is correct?
- EM-5 pin 2 "brown wire" -> GEA24 J243 pin 23 "Fuel Flow" (I have confirmed continuity of this wire from pin to pin).
- No other fuel flow connections (gnd, +12V, etc)
- GEA24 Fuel Flow input active. I have tried setting it as a "Floscan", an "FT-60", and "Custom 0-5000Hz", and K-factors of 304, 3040, and 30400 (my former setting was noted as "304").

My EM-5 also had a software update to support the newer style programmer, so it's possible the issue lies there, but I unfortunately don't have an ocilloscope to test the pulse output is active.

Applicable to EM-6, on page 62 of the manual is this information. Obviously may differ from EM-5 but download the manual and see how much is applicable? Pretty good amount of info on the setup for it.

“Optional Fuel Flow Output to Engine Monitors”

 

[jwyatt]

Applicable to EM-6, on page 62 of the manual is this information. Obviously may differ from EM-5 but download the manual and see how much is applicable? Pretty good amount of info on the setup for it.

“Optional Fuel Flow Output to Engine Monitors”

Thanks. I'll see if the test output mentioned here exists in the EM-5. I do wonder if there's a need for an external pull-up on the GEA...it was not needed with the AFS.

 

[agent4573]

I went through this exact same thing. No resistor is required, no other connections required. I ended up having the wire in pin 22 instead of 23 because of the way the connector is labeled. Make sure the wire is in the 4th hole from the end of the connector. The setting in Garmin should be for Ft60, approximately 30,000 on the k factor. If the unit was supplying your old screen with valid pulses, why would you assume that the output was bad and need a scope? In the setup menu you can scroll through and make sure you have a value for injector output pulse and that the fuel flow lock value is all zeros. If those are true you should have a good output from the SDS.

 

[jwyatt]

No resistor is required, no other connections required.

Thanks for the confirmation.

I ended up having the wire in pin 22 instead of 23 because of the way the connector is labeled. Make sure the wire is in the 4th hole from the end of the connector.

Checked this last night, it's in the correct hole (4 from the end) for pin 23.

why would you assume that the output was bad and need a scope?

No assumption, just an understanding that having changed something on both ends of the wire at the same time makes it harder to authoritatively troubleshoot.

In the setup menu you can scroll through and make sure you have a value for injector output pulse and that the fuel flow lock value is all zeros. If those are true you should have a good output from the SDS.

Menu settings all look good, I'll recheck things again before calling Ross or G3Xpert.

 

[Ralph Inkster]

Thanks for the confirmation.


Checked this last night, it's in the correct hole (4 from the end) for pin 23.


No assumption, just an understanding that having changed something on both ends of the wire at the same time makes it harder to authoritatively troubleshoot.


Menu settings all look good, I'll recheck things again before calling Ross or G3Xpert.

Call Ross. Can't remember what the K factor is but it is quite different from your typical Flowscan or Red Cube type sender.

 

[jwyatt]

Update: still flying with no fuel flow indication. Worked with SDS to confirm all settings were correct, put a scope on the line to confirm it's pulsing as expected. After some suggestions with no results, G3Xpert is escalating to "the engineers". Obviously fuel flow isn't a critical indication, but it is handy to have; this is the only remaining quirk in my panel overhaul.