Is it normal to hear a walbro 255 hump occasionally..?

Most of the time it's inaudible, but very occasionally I hear it hum for a second, usually when pulling up in traffic. IIRC there is a variable speed controller running the pump on later cars, is this what I'm hearing..?

Cheers,
Jason

 

I own a Classic Uk turbo MY95, sometimes I can hear a whine sound from the pump, mainly on start up and also a Groaning noise that cuts out once the fuel pressure is reached. Ask a question a day or so ago about these sounds but no response from this site,so did a Google search and found it may be due to a U/S or after market fuel pressure regulator, causing over pressure in the system, but the car runs ok (It has been doing this for 2.5 Years) so I am leaving well alone!! Good luck with your inquiries...