The engine came from a 2016 370z which should be compatible. I have done a lot of research and replaced the crank sensor and cam sensors to no luck. I also suspected the flexplate was damaged or installed incorrectly during the swap but after dropping the transmission today it (the flexplate) was installed on the proper aligning pin. I uninstalled it and all the teeth for both the started gear and CPS spokes appear to be straight and the plate is not bent from from what I can tell. I plan on replacing the flexplate just to rule it out since it is not a large cost. Could the engine harness be an issue? I heard it was potentially a cause of the problem. As far as testing continuity I tried to get a good understanding from the workshop manuals but struggled to find the circuits mentioned in the troubleshooting. The engine has less that 25k on it so it should be in time and when it runs it does run well with no weird noises. The ECU was also replaced and re flashed by the dealer to mate it to the engine. Any help is greatly appreciated! I also apologize if this exact question has been answered but I have been looking for weeks for a solution online.

 

My guess would be the flex plate as well . Seeing that the donor is a 2016 those cars came with a 7 speed vs your 5 speed. I'm not sure if there is a difference in the number of teeth but highly likely. If you did order one another one it should be for your 5 speed and not newer engine but then again you say your ecu was updated. Either way your transmission is still 5 gears. I hope this help's