Why is my engine not firing?

Inspect and test the idle air control motor, EGR valve and throttle position and manifold absolute pressure sensor-

First thing you need to do is to drain the gas tank and put in new gas. Flushing of fuel tank is recommended. Next would be to purge the fuel system and you should be good to go. Replacement of the fuel filter is recommended but don't do it until you have purged the system.
At bottom of fuel tank there is a drain plug. Release the drain plug to drain out the water.
At fuel rail in engine compartment, disconnect it and put hose into a container to collect fuel that comes out. You can either cycle the ignition switch on/off for 2 second intervals to use the fuel pump to purge the lines or manually activate the fuel pump by means of applying battery voltage to it. Once fuel stops coming out of the lines, reinstall fuel lines and you can top up with new gas and try starting.

Might take a while of cranking to get it going.

You'll have to check your maxi fuses to see if one is blown, it may have shorted soemthing else out as well, have it checked out and explain when you take it in what happened.

Hi,

Chances are it is either a fuel or ignition related issue. Try this. See if it starts for a couple seconds and then stalls. If it does, then we know it is fuel related. If it still doesn't start, then you need to check for spark to the plugs.

Here is a link you may find helpful:

https://www.2carpros.com/articles/car-cranks-but-wont-start

Try what I suggested and let me know the results.

Take care,
Joe