Today I’ve experienced the same issue, after updating my 2.5 APM board to 3.0.3 (from 2.78), I reset all the params to default values. I changed a few settings, calibrated etc. (all the necessary stuff for an EZ2), everything looked fine but at the field I noticed that the motor woudn’t start in any auto pilot mode. The only mode I could start the motor was MANUAL. MIN ans MAX THR values are 0 and 90%. I also changed THR_PAS_STAB to 1 and so I had manual motor control in FBWA and STABILIZE. Still no luck with the rest of the auto modes: RTL, CRUIZE. APM just don’t want to make throttle management.
I’ve been using APM 2.5-2.7 for years and I guess I have some experience with it but this time I am helpless, I really don’t know what else to try.
First of all I have to mention that I flew this hardware setup for over an year with no issues at all: Easy Star 2, APM 2.5 board, MTK 3329 GPS (is mounted between the wings and it has 8-10 sats every time), current sensor. As I put the board deep inside the foam (the USB was inaccessible) I did not change very often the firmware, most of the time I stayed on 2.7x version. Recently I upgraded to 3.0.0 I, I kept the old settings and I did not notice any issue during flight.
After that, willingly to experience the new features of 3.x firmware, I upgraded to 3.0.3 and started indoor tests (of course, no GPS lock), I just visually tuned PIDs, recalibrating calibrating voltages, compass. BTW, one day, after an update of Mission Planner, I could not start compass calibration. I spent a whole evening trying different approaches with no luck. Next day in the morning another MP update was available and guess what was written in the change log? “Solved some issues with compass calibration” .
So, could this APM:Plane version - 3.0.3 - have a problem, maybe APM 2.5 board are not entirely supported by this software version? Eventually, I guess I’ll go back to 2.78 but I don’t know exactly what Mission Planner version to use, every new MP has new buttons which might not have correspondence with APM:Plane 2.78.
Thanks, I found it in the very next morning when the latest MP update poped up. After this the calibration worked.
Anyway, I tried 3.0.1 firmware version and still no luck with the engine in auto pilot mode. So I uploaded 2.78b, fresh settings… the engine is working again as it should. All the tests (with different fw versions) were carried indoor, with the plane next to the window so 3D lock was achieved. For me case is closed, I’ll stick to 2.78, it will suffice my needs.