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Old 02-06-2021, 11:46 AM
Ralph Inkster Ralph Inkster is offline
Join Date: Feb 2008
Location: Calgary, Alberta
Posts: 1,282

Michael- try in the setup prompts to change the O2 type, maybe another choice may play nicer with your O2 sensor pkg. Another possibility might be in the advance settings where you can set the 0 - 5 volt scale and afr range. Ross talked about this in the SDS 2020 thread (can't find it right now).

I originally had an AEM O2 sensor pkg and found it would show a display error on the SDS controller sporadically. I think I was getting AFR spikes beyond the 9:1 to 19:1 scale (probably caused by my Acc-pump Lo & Hi settings) that would result in display errors. I can go to my #1 display screen on the SDS and than touch the +10 button to reset or clear the error messages.
Even with the error messages, I could still export the O2 data to my laptop running the SDS Dash datalogger. I am now using the Bellenger O2 pkg and rely on it's AFR display for visual monitoring, but still wire it's output to the SDS so I can us it's data for the SDS Dash datalogger.

Jclemens- I prefer the AFR information going to the SDS & SDS Dash data logger because it pairs up the specific sensor inputs that calculate the fuel map all together, you get a perfect time line match with the O2 sensor and see what fuel map setting (AT, TPS, RPM, MAP, TEMP) is causing a jump in the AFR at that specific moment.
Your map seems to place much more emphasis on MAP values & changes compared to my setup. My fuel map places more emphasis on RPM/FUEL as a base and have MAP (& the other sensors) react in a less dramatic way, less AFR swing.
I looked over your datalog file and really couldn't pull any useful conclusions as there were climbs, descents, rpm & assumed power changes during the flight.
My procedure for a fuel mapping test flight would be to climb out to a specific altitude and set a specific rpm/power setting, say 2200, hold it there for a couple minutes, change rpm to 2300, again hold for a couple minutes & work up the rpm scale, all flying consistently so flight parameters don't change. Note I have fixed pitch so test process is simpler than would be useful with a C/A prop setup. Than I'd repeat whole process at a couple thousand ft higher. I would also set up climbs a varying speeds (different engine loading) & hold constant climb to get data from those flight conditions. The data log file will show each test segment and how the sensors are affecting the fuel map at that point and it's resulting AFR.
You could set rpm and move up the scale of throttle/map, holding for a few minutes each. Than up the rpm by 100 and repeat the throttle/map scale, repeat these sequences up as high as you want. This would give you a clear picture how your fuel map settings are working as they affect the AFR at each point.
Sorry for being long winded on this, just trying to possibly save you some of the folly I went thru.
built a few RVs, rebuilt a few more, hot rodded more, & maintained/updated a big bunch more

Last edited by Ralph Inkster : 02-06-2021 at 02:57 PM.
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