It's not that it can't pass smog, but rather that in it's current configuration, it won't pass in CA.
When I gave that car (shell) to the guy you bought it from, he transplanted the engine from his 90 GSX to the VR4. Oddball year for DSM's, so some things were different than what should have been in the '91 GVR4.
I'm almost certain that the smog equipment is incorrect for what
should be on that car (again, coming from a 90 GSX). Here's a good place to start..
Make sure everything matches the CA config.
...might I also suggest you pull the ECU and determine where that came from. I didn't supply one when I gave him the shell.