As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO MAKE INSTRUMENT AIR PRESSURE AT LOW RPM, INSPECTED SYSTEM AND FOUND THAT THE PUMP WAS MAKING SMALL CHUNKS OF CARBON FOUNDED IN THE REGULATOR AND INLET FILTER. PURGED SYSTEM AND CLEANED LINES IN SYSTEM. NEW INLET AND INLINE FILTER INSTALLED. NEW PUMP INSTALLED, SYSTEM GROUND CHECKED, CHECKED NORMAL.