Fuel Tank Noises?

[mySVT]

Hey everyone mySVT here. I'm a long time member and avid supporterof CEG. A few weeks ago I noticed the most obnoxious noise coming from the rear of my svt when driving over any uneven road surface. In attempting to describe the noise I would say that it sounds like two pieces of hollow plastic bouncing around; almost as if you took one of those big Rubbermaid storage boxes, threw a piece of tupperware inside of it and shook it around.
I traced the sound to the fuel tank, If i bang on the bottom of it from underneath the car you can hear it. I pulled the fuel pump/sending unit assembly today and discovered that there is a black piece of plastic inside the fuel tank that surrounds the fuel pump assembly serving as some sort of housing. This piece of plastic seems to be the culprit making the noise. If I smack it, it makes the noise I described above. My question is has anyone ever heard of this problem? Also does anyone have any idea on a solution? The only thing I can think of is looking for a new fuel tank as I have no idea how that piece is fastened inside the tank.

I have included a picture of what I am referring to.


Thanks,

mySVT

 

[striker2]

its hard to tell from the small picture but it looks like the retaining ring for the fuel sending unit. not sure how it would make noise though. is your car returnless? if it is you could install the upgraded sending unit which requires you to cut that ring out. you get a nice new fuel pump and dont have to change out the tank.

 

[TRicker]

My E0 is doing that too. i replaced damn near every bolt in the rear suspension only for it to be the tank. it goes away slightly on a full tank, but still does it. i never pulled the pump but i figure something in that whole assembly has to be worn out or something, maybe a rubber seal or something?

 

[mySVT]

Ok so yesterday I went back out and took some more pictures in order to try and help explain. The car has the return style pump, which I replaced yesterday while I had the old one out. When I reached into the tank and tapped on the black baffle circled in red in the picture below, it rattled on the one side because there was a gap between it and the bottom of the fuel tank. I cut the bottom edge of a 5 quart plastic oil bottle which acted like a spring, and made a wedge out of it which I then reached down in the tank and placed it underneath the baffle to take up the space. When I did this the rattling sounds ceased.





I then proceeded to wrap up the project which I have a few pictures of, but when I took it for a test drive today, the rattle was still there! I don't know if the wedge I placed in there popped out already, which I find hard to believe, or if the rattle was coming from somewhere else the whole time...very confusing/frustrating. On the plus side, the new fuel pump primes quickly and quietly! I have a broken spring at the rear driver's side wheel. I'm going to tackle that on Saturday; maybe that has something to do with the noise. I'll keep everyone updated.

 

[Tony2005]

The fuel line and vapor recovery lines run on top of the fuel tank, below the floorboard of the car. Check the "hooks" for the lines that may have rusted out. When I snagged the a vapor recovery line on a broken branch 5 years ago, I had a sound similar to that. It was obvious what the sound was in my case as the line was almost touching the road.