Me and a friend just replaced all of the fuel injectors for my z32. After replacement and re installing the intake manifold, etc. It makes a grinding noise when I try to start it.... It has never had the issue before.. so Im not entirely sure what it could be. The only thing I can think of is that were not completely sure all of the wires were connected properly
Here's a video for reference

Thanks

 

Sounds like your starter is messed up. I suggest replacing it.