I have an 81 zx and the fuel pump seems to always make a loud humming sound and does stop. i dont know if its the stock pump, i've never checked. i was wondering if its suppose to do that?

 

yeah those things are really loud...the buzzin means its working!

 

the real question is, is it suppose to be continous?

 

yeah i think its always suppose to be on at least mine is...unless sombody messed around with it or got a new pump and it just goes on when you start the car (like newer models where you can hear it buzz when you hit the ignition to get fuel in for that initial start)

 

the fuel pump does prime the system upon powering up the car, switch on but not crank. but it should shut off. something with the fuel pressure sensor

 

my 280 does the same thing. I was told when I bought the car that it was normal