Replace fuel pump but why car won't start?

If your fuel pump is in the gas tank the fuel pump is cooled and lubricated by the gas. If you run out of gas and keep trying to start it many times you can damage the fuel pump. If you have a older car you can try putting a little gas in the carburetor and see if it cranks, if it cranks with gas in carburetor you know it is a lack of fuel problem. You might try spraying starting fluid in air filter but to much can damage your engine. Some links below may provide some help.
https://www.yourmechanic.com/question/car-won-t-start-after-it-ran-out-of-gas-and-was-filled-again
https://www.bimmerforums.com/forum/showthread.php?1881026-Ran-out-of-fuel-now-won-t-start-please-help!
Your vehicle fuel pump can run and pump gas but depending on your vehicle you may not have enough fuel pressure to run. I would check your fuel pump fuse and relay and fuel inertia switch/fuel pump kill switch if you have one. I do not know why running out of gas would cause them to fail but it is something to check.

When you smelt fuel, It was flooded. Your best bet would be to replace the spark plugs. Gas will foul them out, just like oil.

fuel pick-up in tank is blocked it has a sock over the end as a gross filter to keep out any big junk from getting sucked into the pump and causing damage to it. the sock can get so plugged up that no fuel will flow, causing the pump to run for a short time then with no fuel flow to cool it it trips the safety and shuts off

Your fuel pump is on its way out it's giving you signs what you see is what normally happens when fuel pumps go out best of luck to you

sounds more like the ECM than a relay, to me.

If it is a 3.8 engine change the crank sensor,they go bad on the 3.8 engines.

After for setting for so long it is possible the pump picked something up and it clogged the injector.

About the only thing within time that can change from sitting that would effect starting performance is the fuel. The fuel is probably evaporating from your lines and other areas of the system.
Try turning the key to start with a pause till you hear the fuel pump stop, THEN turn it to run.

if you can't hear the fuel pump cut in for a couple of seconds, check the fuse. Check the relay, or replace it with a known good one. See if you have power to the fuel pump. If you have power, your fuel pump is in need of replacement.
When you run an electric fuel pump out of gas, you should always cycle it about 10 times before you try to start the engine. That is, turn the key to on for a few seconds, and then off, and repeat. You need to get some fuel up to the engine.