My 98 explorer turns over but will not start. The fuel pump kicks on for half a second, then immediately shuts off. Does anyone know how to go about fixing this?

Your truck has two sensors that are in control.There is a camshaft sensor that controls when the fuel injectors open according to camshaft position.If this one is bad the fuel injectors wont open and the engine wont get any fuel.It also has a crankshaft sensor that is in control of allowing spark to the propor spark plug at the right time.If this sensor is bad you will not have any spark to any of the spark plugs.The fuel pump will only run for 2 to 3 seconds unless the motor starts,it is designed that way and it primes the fuel system and brings it up to pressure.(aprox 40 psi )