As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL WEMAC EMITTED A STRONG SULFUR SMELL INTERMITTENTLY IN DIFFERENT VALVE AND PAC POSITIONS, AS A RESULT CANNOT DETERMINE SOURCE. RAN ENGINES AND APU, USED BLEED AIR WITH NO ODOR FROM WEMACS. INSPECTED COALESCER SOCKS WITH NO DISCREPANCY OR ODORS NOTED. SYSTEM CHECKS GOOD IAW CESSNA 750 MM CHAPTER 21-21-00.