Started once but now it wont cant hear the fuel pump kick on should i be able to hear it

Year,make, and model? When was the last tune up done? Air filter, fuel filter? Could also be a bad fuel pump.

Hopefully you checked the fuse and relay for the fuel pump before spending the money to replace those items. If you're not hearing the fuel pump kick on, you aren't going to have pressure. P0300 is a misfire code that was probably stored due to the engine failing to start since there was no fuel pressure.
Check that there is 12V at the fuel pump if you can't hear it. You will need to have someone turn on the key because the power to the pump only stays on for a few seconds unless the engine is started immediately. This allows it to prime the fuel line. Once you have confirmed that there is power to the pump, check the fuel pressure at the fuel rail to rule out a pressure regulator problem.

try priming the system it just might have air

you should change that relay

a lot of times if u turn the key on and off without startig the engine in a quiet area you will hear the fuel pump kick on do this a few times then try to start the engine. If you cant hear the fuel pump that may be the problem, another solution would be to remove the injecters and clean them

check crank relay and crank fuse

You need to change the fuel pump.

When you replaced the fuel pump did you replace the connector on top of the sending unit

Check to see if the fuel pump is kicking in,
when you turn the key on without starting the van you should hear it kick on for about 2 seconds,

It could be...
A clogged fuel filter...
Blown fuse for the pump..or bad pump relay..
No gas
Bad fuel pump

IT sounds like the fuel pump to me.You will have to put a fuel pressure gauge on it and see that it has more than 50 psi.The engine needs between 50 to 60 psi to even run.I think you should just change the fuel pump.