What is wrong with my FASS
 

I wish I could post a video but it’s make like a pinging sound while it’s pumping. I afraid to drive it. I should be able to email the video if someone wants to here it

Could this noise be something as simple as a loose mounting bolt that is vibrating

I guess I should point out that I’ve only owned the truck a week and didn’t install the FASS.
Yesterday I changed the water separator and the pinging stopped but now it’s sounds like it’s surging. .
I think it’s possible air is getting into the system through the hose or its past due for a fuel filter.
So I ordered new hose from FASS and ordered a CAT fuel filter. So if none of this works the pump is probably on its way out.

I certainly hope you called FASS and asked them.