After replacing alternator, engine cranks but won't catch.

Have you tried jumping it? The engine requires approximately 9.5- 10 volts to crank depending on the battery and engine size. The computer requires an additional 1- 1.5 volts. A battery can have enough voltage to crank but have nothing left for the computer to run. The bad alternator could have left the battery in that charge where it seems ok but isn't.

Why is my serpentine belt not turning car wants to start but won't any ideas both starter and alternator are new