Friend’s car has a buzzer sound while running. Like the key is in the ignition of a 70s car.
Is this normal? Or does this mean the fuel pump is dying?
Yes, a pump can whine or growl. Whether that is the case here I do not know. Remove the gas cap, put an ear to the filler spout, and see if it can be verified that way. If it is the pump causing this noise then that will likely mean the pump is on the way out and may be struggling against a partially clogged fuel filter.
A pump buzz can also be caused by a distorted fuel tank if there’s been a collision, high centering leading to tank indentation, etc. The bottom of the tank brushes against the pump strainer or module and which then leads to a vibration induced buzz or rattle.
It could also be a loose exhaust part.
Does it whine when the key is turned to ON without turning it to START? If it is the fuel pump, it should whine then too.
Yes, the buzz/whine comes on before the engine is actually running.
Year, make, model?
Tester
Sounds like the pump is on its way out.
I agree that the pump is most likely on its way out.
As I learned (the hard way) with my Volvo, replacing the fuel pump promptly when high-pitched noises appear is a good way to avoid being stranded.