What was found
DURING CRUISE, EXPERIENCED MULTIPLE ECU FAILURES ON RT ENGINE, FOLLOWED BY MODERATE POWER LOSS AND ROUGH RUNNING ENGINE CONDITIONS. ECU WAS RANDOMLY SWITCHING FROM SIDE A TO B IN AN ATTEMPT TO ISOLATE FAULT. ENGINE WAS VISUALLY INSPECTED FOR ANY ANOMALIES, PARTICULARLY IN THE MAIN ELECTRICAL HARNESS. PERFORMED MAINTENANCE DATA DOWNLOAD OF FLIGHT DATA AND SENT TO TECH SUPPORT FOR ANALYSIS. OIL PRESSURE SENSOR WIRING, FOUND INSULATION CHAFED, WIRE GROUNDING OUT AGAINST THE MOUNT SUPPORT FOR THE BLOW-BY ASSEMBLY, AIR/OIL SEPARATOR, CAUSING THE ECU TO SWITCH BETWEEN A AND B POSITIONS TRYING TO ISOLATE FAULT. VISUALLY INSPECTED WIRING FOR ELECTRODE DAMAGE, WIRE WAS INSULATED, REROUTED AND SECURED. PERFORMED RUN-UP, AND ALL ENGINE OPERATIONAL PARAMETERS WERE FOUND TO BE WITHIN LIMITS;