Unless there’s something special about the bike that would make it worth investing significant time and money into your project, I’d sell it and look for a better donor.
EDIT: On my laptop now, instead of one finger typing on my tablet.
If you decide to proceed, then you'll likely replace the controller and display (should be purchased as a set), but unless you are very lucky, the torque sensor will add significant cost to implement, since you will need a controller (or a Cycle Analyst) that is compatible with that model of torque sensor. Since there's no information readily available on what it is, you will need to disassemble to access it and hopefully find a model number or other identifying information. The workaround would be to add a cadence sensing PAS, attached to bottom bracket, if that's acceptable.
If the original controller was integrated into other accessories on the bike, such as lights, then you'll probably need to work on that system separately and add a buck converter to supply the power.
If you go with a cadence PAS and can deal with the accessories (there are plenty of threads on this. I recall a member
slaphappygamer, or something like that, that modded his factory bike and dealt with lighting issue, so you can search that), then you can do this very cheaply, but it's the same thing you'd go through if you started with a normal bike, except you have the motor already, without paying for a broken ebike.
On the motor, you can perform all the tests you need to ensure it functions by following the testing steps for the motor phases and hall sensor in this article:
Testing electrical components of a typical hub motor with a digital multi meter. First take a few minutes and look over the wiring going into the motor for cuts, scrapes, missing insulation and other wiring issues or poor connections that should be resolved first. Smell for...
electricbike.com
There's a sticky in the troubleshooting subforum that includes links to the article above, and more troubleshooting articles. The link is also in my signature below, "
DIY Newb FAQ"
