can not start van, has gas and new battery, lights work,does not crank

would really need to see it but if not actually turning over, could be starter, neutral switch, ignition switch, etc... if turning over but not starting, could be fuel pump, or a spark problem. since it is 4.3, I believe it has the injector assembly under intake. there is the longshot the pressure regulator failed and engine flooded. I may be able to help further if you can be certain it is not cranking at all like no power or cranking but not starting. there is the longshot of theft deterrent as well but don't see that often