What was found
IN NORMAL FLIGHT, THE EFC OFF(ELECTRONIC FUEL CONTROL) ANNUNCIATOR LIGHT ILLUMINATED. THE PILOTS ATTEMPTED TO RESET THE EFC SEVERAL TIMES, FAILING AT EVERY ATTEMPT. TROUBLESHOOTING REVEALED DAMAGE TO THE N1 SENSOR PROBE CAUSED BY THE N1 PICK-UP, AT 24 EQUALLY-SPACED TOOTHED WHEEL INTEGRAL TO THE COMPRESSOR SHAFT. MINUTE DAMAGE WAS INFLICTED ON THE PROBE, CONSISTING OF AN EXTREMELY SHALLOW GROOVE CUT INTO THE END OF THE PROBE. THE TOOTHED WHEEL DID NOT APPEAR DAMAGED. THE PROBE WAS PROBABLY DAMAGED DUE TO THE IMPROPER INSTALLATION. (K)