Sorry to hear that. There are reasons why it burns. It could be there's printed ckt that weakened due to long over current or there could be a fault in the line/load. You can investigate based on the burn circuit. If the printed ckt was burn out, it might be high resistance already that caused your fuel pump to stall, otherwise it's overloaded due to blocked fuel injectors. Another is when ECU detected an increase in rpm after acceleration delay, it will ramp up pump voltage to feed more fuel but if there's internal blockage it will overload. Actually ECU can handle that if it happened within it's waiting time but if not and happened many times or for a long time, it can cause damage to the ECU. Try to feed air into the fuel line to check if pressure holds to confirm fuel resistance or blockage. So far, I don't have schematic of ECU but there should be only few high powered ckt there, the one that drives the glow plug, starter motor and the pump. Check the burned device ckt that feeds those equipment. You said that one output MOSFET became shorted, it indicate a sustain fault or very high current. After you fixed the problem you can replace the broken parts and resolder burned ckt.