Having reinstalled the drivetrain, I wanted to start up the Corvette to check for any issues, fluid leaks etc. It fired up once, then died after a few seconds and would not start again. I noticed that the fuel pump was not priming when I turned on the ignition. The fuel pressure meter I've installed on the fuel rail also confirmed zero fuel pressure.
I erased all DIC fault codes, removed the fuel pump relay and jumped the 12V supply, but the fuel pump would not run. I came up with list of possible causes; fuel pump faulty due to car being stationary for a whole year, clogged fuel filter, wiring passing over torque tube damaged on removal or reinstall of torque tube. Oh no... removing all of the drivetrain again?! A new $250+ fuel pump assembly?!
"c5 corvette fuel pump not priming" on Google came up with multiple hits on corvetteforum.com, and in one of the threads the ground post on the frame inside the LH rear wheel was mentioned.
Guess what - I had only put the eyelet connector and nut in place, but not tightened the nut. A minute later the V8 roared to life!
Several other systems are also using this post as a ground reference. The ground point is named G401 in the service manual and is used as common ground in splice pack SP400 - where all of the rear sensors and lamps are connected.