2 things:

RPM sensor (banana style) is very sensitve and ANY dirt can make it stop working. I had the same problem. Take it out, take off the shrink wrap and clean it. Mine worked fine then. Also theck with another magnet. When not absolutely positioned it can misread or not read at all.

When you short the leads (glow / starter) on the fadec you can repair it yourself The fadec has a thin wire strip on the surface which acts like a fuse. When you shortout the leads (done that myself) the fuses burns and protects the circuits. Just open the fadec and theck for any burned traces (fuse trace is on the side). I have another fadec with damaged to the fuse trace also due to a bad starter motor.....

My motor has a ngv that is just a little to small. I noticed the turbine wheel rubbing the ngv. I cleaned it up and rebuild it and it looks fine again. Rear bearing is in excelent condition, even at 167k rpms Wren ngv seems to hold it very nicely. A few hot spots but not a real problem. CC looks ok and has even burn marks allover.