I have motor efficiency higher than 100%.

It is absolutely not normal having the output mechanical power superior to the input electrical power. As long as you observe an efficiency >100%, there must be an error somewhere in the measurement.

In our measurement, electrical power = voltage x current; mechanical power = torque x speed. You may need to isolate each of the parameters in order to fully run the troubleshooting.

• If you are using the LiPo battery, check if it is fully charged and if it is within the acceptable range of the output voltage (1S : 3.3 V to 4.3 V).
• Generally, current is very stable as shunt resistors or hall sensors are reliable. If unsure, check with a multimeter in a low power mode.
• Check the RPM probe reading:

• If you are using the Series 1585 electrical RPM, make sure that you have entered the correct number of poles. 
• If you are using the Series 1585 optical RPM, make sure that you have properly wrapped the rotor with black tape to hide all reflective engraving, and have a correct length of white tape, as well as a correct distance between the tape and the probe.
• If you are using the Flight Stand optical RPM probe, also make sure the black tape, the length of white tape and the distance. 

• Compare the measured data with the published data from the propeller manufacturer to see if you obtain a similar thrust given the same RPM. If this number is close to the advertised value, that usually means you have a correct RPM value and you may continue troubleshooting for the torque; if you don’t have a correct RPM value, you may consider replacing an optical probe, or switching electrical/optical RPM reading.
• Please make sure that you DO NOT connect optical and electrical RPM probes simultaneously. This will drive the software to crash.
• If you are using the Series 1585, recalibrate the load cells following the wizard in the GUI and try to run the tests again.