I had exactly the same Fuel Fail on the initial ground run following a JetCat service and the 5.0 ECU Upgrade. Duirng the run, the sound was very different, a deeper note with a very pronounced rumble. All of a sudden, it shutdown with a Fuel Fail message. I ran it again, and everything was back to normal, so I put it down to purging all the fuel lines, and possibly uneven combustion causing the rumble.

Hopefully Matt can describe the faults that generate a Fuel Fail message as it's not in the manual.

Paul