[72Blazer San Jose CA]

Does the engine crank over normal but does not start? Or does it crank over very slow? Put a volt meter on the battery and crank over engine if it stays above 9.6V battery and starter probably ok. Now if it cranks over ok but takes a few times to start that may be your fuel pump assembly in tank.
Put a fuel pressure tester at the test port on the fuel rail. Pressure when the
the key is turn to on position should be around 40PSI and hold if it drops the fuel is draining back to fuel tank then needs to crank over to reprime fuel line.
Other ways to loose pressure right away is injector stuck open or fuel regulator stays open.

Carlos