why will it crank but no start- on 2004 Ford Explorer

just installed good used engine ..ran great all day next day cranks but no start

Asked by for the 2004 Ford Explorer
3 answers
had same problem last year. turned out to be a dead fuel pump. should be able to hear a slight short whirring sound after turn key before the engine cranks. this is the pump priming the line for fuel. if no whirring sound, it's a good bet that it is the fuel pump. b sure to ask for pump/sender combo kit to replace. i made the mistake of just the pump, had to go back for a sender.
Got spark? Got fuel pressure? Need to know! Can't guess at it, be wrong every time.
ck for spark and fuelpressure to start with and also all the fuses. could also be the inertia switch if its no fuel pressure