Humming sound just after ignition is switched on

[t_marat]

Car started making a humming sound, as if something is grinding against something else, just after the ignition is switched one. This lasts for only a couple of seconds then stops. Pump is already noisy, but this sound seems to come from under the front hood. You can actually feel it, not just hear. Sometimes this also happens when the engine is running. It could be happening more frequently, but while driving you won't hear it.

[632 Regal]

aux pump pulsating and transmiting vibrations to the front??

[Morgenster]

Or ICV? I get the humming sometimes on 'electrics and ignition on' before I crank. Sometimes also when I tap the throttle over idle and let it fall back to it.

[t_marat]

Is there an auxiliary fuel pump?

[Morgenster]

Is there an auxiliary fuel pump?

Not up front. I remember reading about some BMW models having two fuel pumps but those were in the rear. One for fuel pickup and filtering, the second for pressurising the fuel lines to the engine.

I'm thinking it could well be the aux water pump even if I had the symptom when blipping from idle. Does it sound like the sound travels from the front-left to the dash and sides?

[Jon K]

you're definitely hearing the aux water pump

[t_marat]

Will an auxiliary water pump ran even if the heater is off, that is temp regulators set to minimum level and blower off?