Autotune limitation(?)

I was trying to autotune on a miniquad with 2300kv Sunnysky motors, 3S and 6" props.

Autotune starts well on the roll and then just stops, no matter how long i wait, and even on no wind day when I didn’t have to correct position

Configuring the PIDs manually I didn’t see anything special: stabP at 7, rateP 0.13, rateI 0.15 and rateD 0.009
These are not perfect (im opening another thread for this problem)

I would really like autotune to work, I read somewhere that it doesn’t go above certain threshold of PID tuning but I don’t remeber where and couldn’t find it.

Is there such limitation? what is it? can it be raised?

This was on AC3.2-rc3 and also tried to downgrade to 3.1.5 and it still didn’t work.

I merged some questions to this thread:

http://ardupilot.com/forum/viewtopic.php?f=80&t=8960

There is a log of the autotune there.