The car is leveling itself out. You can test this theory by letting that noise stop. Then jumping on the bumper will make it unlevel and you will hear the noise again.
Yes
Yes it is priming the system
Hard to answer. Without starting the engine, have a mechanic check it out.
Depends on the engine. A fuel injected engine will run the fuel pump to prime the engine. A diesel engine might have glow plugs run prior to starting. Some older heavy equipment engines had a gasoline pony engine to get the crankshaft turning prior to starting the engine.
The most evident problem would be the engine cranking for long periods of time before starting. banging on the fuel tank can sometimes get the pump temporarily working again.
Yes, if the relay is defective the pump will not run, and the engine will get no fuel.
Turning the key to only the on position, the pump will only run for a couple of seconds to prime the system. Turning the key on and starting the engine, the pump will run and keep running as long as the engine is running.
If you turn on the ignition key without starting the engine you should hear the fuel pump run for a few seconds. If you do not check the fuel pump fuse and replace the relay before proceeding. If the fuse is good and the relay is good then you know the pump is more than likely defective.
Your new fuel pump is apparently defective. A fuel pump is required to supply fuel to the engine, and the engine cannot run (and of course not start) without a supply of fuel.
For 2 or 3 seconds you will hear the fuel pump run , before starting the engine , when the ignition key is turned to the on / run position
If you turn on the ignition key without starting the engine you should hear the fuel pump run for a few seconds. If you do not check the fuel pump fuse and replace the relay before proceeding. If the fuse is good and the relay is good then you know the pump is more than likely defective.
It wont stop starting, it will pump oil out of the turbo and discharge blue smoke.