1997 Chevrolet S-10 engine problems.

i have a 97 s10 that i cannot get to start I've replaced map sensors, spark plugs and wires, distributor cap, and fuel pump. the truck will get fire to the plugs but will not turn over, I've also replaced the cam position sensor as well, I've tried to start it will starting fluid and the truck still will not start, your help on this would be greatly appreciated.