Fuel Pump Noise

[cygnusx1]

My Walbro 255lph external pump has slowly began making a lot of noise heard inside the car. It sounds like a dishwasher drain with a little bit of marbles rattling around in it. Sorry, best description of the noise I can do. It sounds sort of like cavitation, but my AFR's are right on at all speeds, and the fuel pressures are right on. The funny thing is that at idle, I can really hear it loudly while sitting inside the car. If I go outside and stick my head near the pump, I hear nothing unusual. From outside, it sounds like a nice clean running electric pump buzz. The rubber isolators are intact and the pump and bracket don't seem to be rubbing on the underside of the car. Could a bad pressure damper cause the noise?

 

I am going to try a few things if I get time this week to isolate it. I am tempted to order a spare Walbro because the sound is so bad inside the car.

[Flexicoker]

my Walbro is ridiculously loud. I can hear it over the engine most of the time. I though something was wrong at first, but it seems to work fine. I will not be ordering another pump from them.

[Clifton]

My external Walbro is pretty quite. I did have a Paxton pump that you could hear down the street. The volume wasn't so great on it either, so I went with the Walbro.