Did you start the engine with the check valve removed?
Was there ANY Black Residue that would appear to look like Black Pepper in the base of the check valve?
If the engine will run with the ck valve removed, re-install the ck valve & start the engine but leave the return hose dis-connected. If the engine runs with the hose disconnected but will Not Run with the hose re-connected then the return line may be stopped up.
If the engine starts & runs during any of these tests look to see if you have fuel / pressure coming from the fuel return hoses back to the ck valve. If you do then there is an injector that is allowing cyl pressure to enter the fuel system, either on the delivery or the return side- or Both!
This is a condition that will drive you Nutz!
But regardless, bottle feed the suction & disconnect the return & see what happens. If this engine won't run with fuel return disconnected & being bottle fed then you have a mechanical problem with inj pump and or injector / injectors.
By the way that glass ball in the Housing Pressure Ck Valve CAN be Dug outta there & the truck will run without it to get home. But the inj pump will loose it's prime by Siphon Action over night. To prevent this keep the fuel tank as full as possible & park the truck Nose Down as Steep as possible & it will start the next morning.
Good Luck!
