Car has fuel, spark and turns over but won't start

I have a 1995 dodge neon that has 89,657 miles with a 2.0 sohc motor. We just purchased the car, It did not run when we bought it. The bottom end of the motor has nothing wrong with it. It turns over, has spark, and has fuel presure at the injector rail. I know that the timing is right because the marks line up. When the motor turns over smoke comes out from the tal pipe and sometemes it will shoot out fire. We have tried putting a new computor in and that did not help. Does anyone know what is wrong with the motor.