TSDZ2 Torque Problem

Joined
Jul 25, 2019
Messages
14
I have a TSDZ2 48v 750w that recently started having issues with the assist completely dropping out whenever I start applying more torque. It feels like the torque sensor is reporting values in reverse, with normal flat cruising working fine but when I start going up a hill or switch to a higher gear the sensor value actually starts going down to zero and then I'm left peddling up a steep hill with 0W assistance. I'm running the open source software, so I checked the diagnostic values while testing the bike and the cadence values seem to be reporting correctly while the torque values decrease when applying more force to the crank. I hadn't noticed any issues before this so I'm a bit stumped what the problem could be. Anyone seen this issue before?
Thanks
 
I might be misremembering, but I think there was at least one post in the big TSDZ2 thread about a sensor mounting issue, something coming loose and moving around? Was quite a while back; sorry I can't remember more.
 
hydrinium.h2 said:
....I checked the diagnostic values while testing the bike and the cadence values seem to be reporting correctly while the torque values decrease when applying more force to the crank. ....
Imho if there is something wrong with the torquesensor your calibration values should be changed/drifted too.
Maybe the range of the torquesensor is to small now.
 
Updating this with the answer to my issue.
I took apart the motor and had a look at the torque sensor and the entire shaft was cracked in a spiral pattern which reached both ends of the shaft. I think the crack would have shifted the sensor out of alignment the more twisting force was applied to the broken shaft, like unwinding a spring, hence the symptoms I described.
The rod was actually so warped that it got stuck in the housing, I had to buy a gear puller to push it out since hammering it wasn't working. The failure pattern was almost identical to this post from the TSDZ2 megathread.

20220505_182247.jpg
20220505_182226.jpg
 
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