Are you using Torque Pro-?? I don't think you can check the return rate with a PID- only the balance- and rail pressure. Do you have enough fuel in the tank-?? Have you primed the filter-??
One problem with the LLY is the FICM harness-- At the side of the alternator, the FICM harness tied down with a Zip tie. Cut the tie and pull the wires from the harness and inspect for cuts and wear. The sharp corner of the FICM bracket
where it is tied down to, cuts into the wires. Repair and insulate the harness with a short piece of heater hose.
Here is the balance rate- for Torque Pro- Torque Pro Android app reads balance rates
On Torque Pro home screen, go to the little gear in the bottom left, create profile (I called mine 'Duramax'), then go to edit of that profile, scroll to the bottom to where it says "Very advanced". In the very advanced field input "atz" without the quotes. Click save.
Next go to the gear again, settings, manage extra PIDs/Sensors, Top right corner is a menu button (looks like 3 dots vertical), add predefined set, select pontiac / gm / opel / vauxhall. Return to app home screen.
Go to realtime information, if your balance rates aren't already there, press and hold on screen until "item options" appears, add display, digital display, scroll down till you see Balance Rate (Cyl 1) and click on it, select size (I normally use small or medium), repeat that till you have a new display for each cylinder.
Pair up your bluetooth with your app, fire up your truck and wait. It takes a minute for it to sync with the truck and get actual rates. So if at first you see some crazy number as your rates, like -411.00 or something, just wait a minute, it'll fix itself.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.