What is this whisting noise? Fuel related

[Predator1]

Hi,

Can someone please help me identify this noise. It happens perhaps 1 out of 4 drives. When this happens, the fuel pressure, and temperature are well within parameters, FP is 37psi, and temps are around 35-40C. When it happens, it happens at idle, or when I'm cruising around. The ECU has several fuel related cuts, eg, high temp, low pressure. I've had the tuner check the tune when this noise happens, and everything checks out.

My fuel setup is below:

Frenchy's Performance twin in-tank setup(Not the TE edition, but v1)
Twin Walbro 285 pumps(with check valves - 470lph)
Both Pumps are PWM controlled - @ Idle they BOTH run at low speed, and then at eg 2500rpm they BOTH ramp up to full speed.
-10 feed
-8 return going into a Y with 2 -6's - 1 for the ethanol sensor, and the other to bypass(reduce restriction)
Aeroflow 10micron filter
FTurboSmart P2000


The car drives fine and boosts fine - Just sometimes this random noise appears out of the blues. Last time it happened, I was on 1/4 tank, so I filled it up to 1/2 - Noise still there. I can see the FP consistently change with boost as I drive it as well.

I thought that the ethanol sensor was faulty, so here's what I did:

* While car was idling, unplugged the eth sensor - Noise still there
* Restarted car - Noise went away for about 30 secs, then it gradually picked up volume(louder) - This is what can be heard in the video.

Can anyone please shed some light on this or if anyone's experienced this type of whistling noise?

Excuse the exhaust noise and video - I had the phone by the rear diff where my filter etc is mounted trying to pinpoint the noise.

 

[GTSBoy]

On 2/12/2022 at 9:40 AM, Predator1 said:

While car was idling, unplugged the eth sensor - Noise still there

Well....unplugging the sensor isn't going to do anything. It's not like it's an active component. It's just a pipe.

Have you considered unplugging one pump at a time? If you kill a pump while the noise is there and the noise dies immediately, you've probably found your villain.

Beyond that, it is just diagnostics 101. Open the return pipework and have the fuel not go back to the tank. Drop it into an external bucket. See if it's singing as it goes through a piece of thread tape stretched across a fitting, or something equally stupid. It's always something stupid.

[Predator1]

Yes, sadly I didn't think of it when the noise occurred last time(stupid me, as I was pacing). I've taken the whole fuel intank setup today and everything checks out. Nothing was loose at all. I'll change the socks as they look a little discolored - I hosed it off with 1/2 can of brake cleaner and couldn't see any crap out of it(Onto a while A4 paper).

What does that sound like though?