Fuel pump noise on first start of the day

On my 2015, typically when I put the key into the ignition for the first time of each day (but don't yet crank the engine over), you can hear what I believe is the fuel pump priming.

I've been weary of cranking the engine while the pump sound is occurring since I don't want to interrupt it.

Has anyone here confirmed what the sound is, and does it get harmed in any way by cranking the engine while the sound is occurring?

 

I've always thought it had something to do with smog control. Not really sure.

 

Probably fuel pump, you can crank it though I used to drive a diesel and would wait for a second before you can crank it and it's always stuck to me

 

You could be referring to the piston slap noise. YouTube it but almost all tacos do it. Mine included.

 

No. The noise is before he cranks the engine.

OP, Cranking isn't going to hurt anything...

 

O I didn't read it carefully enough