Thumping Sound from Fuel Tank

[conversation]

Hi,

I have an 09 S Versa HB

I noticed a thumping sound, for a while now, that I originally thought was coming from the engine. But it is louder inside the car than outside. Yesterday I put my ear on the gas filler door, and heard it pretty clearly. I'm wondering if the fuel pump, which I think is inside the tank, is doing the thumping. It's not a real loud sound, just enough to notice and wonder about.

Any ideas welcome....

Oh yeah, it only shows up after I've been driving at least 15 minutes, and I only hear it when stopped, engine running.

[NODES]

does it do it every time after 15 minutes? That way they cannot use the excuse we can reproduce it at the dealership. Fuel pump is under the rear seat I do believe.

[conversation]

does it do it every time after 15 minutes? That way they cannot use the excuse we can reproduce it at the dealership. Fuel pump is under the rear seat I do believe.

Nodes,

It does it every time I drive home from work, but not when I drive TO work. Or maybe there's too much noise at work to hear it. But no, it doesn't always do it after 15 minutes.

The fuel pump is still on the outside of the car, under the back seat, right? Can't be inside the car, can it?

Conver

[Francesco]

FWIW, if your Versa has ABS there will be a small thumping sound from the ABS as it does a self test when you first get to 19 MPH. It only lasts a few seconds and will not occur again unless you shut off the car and start up again.

Frank09 Versa sedan MT-6 (avg mpg = 35 over 7500 mi)

[mosquito_R]

FWIW, if your Versa has ABS there will be a small thumping sound from the ABS as it does a self test when you first get to 19 MPH.

Does the sound appear to be coming from the back? I hear a thumping sound too but I dunno if it's just a one-off thing after each start.

[conversation]

Does the sound appear to be coming from the back? I hear a thumping sound too but I dunno if it's just a one-off thing after each start.

Yeah, it's coming from the back. It always is there when I pull into my driveway, and put it in Park or Neutral, after driving home from work ( 38 miles). It is loudest from inside the car. When I put my ear against the front fender, all I hear is normal engine noise. When I put my ear against the rear fenders, or against the fuel filler door, I hear the thumping very clearly. More like a "dut, dut, dut" kind of dull tap sound.

It only happens after the car is warmed up, and has been driven quite a while ( 15 miles, I guess ? )

[NODES]

A warm exhaust will make a tapping type of noise.

[Francesco]

Does the sound appear to be coming from the back? I hear a thumping sound too but I dunno if it's just a one-off thing after each start.

The ABS motor is in front in the engine firewall on the right side and after its few second test will not calibrate again unless the car is turned off and restarted. Have you checked clearance on the exhaust system in the rear when hot. Does the sound change if the engine is at 1200 rpm? If it is the fuel pump try, shutting off the engine when you get home and turn the ignition back on after 30 seconds and listen carefully for the first few seconds when the fuel pump briefly comes on.

Frank

[conversation]

Actually I don't think my car has ABS. And yes, if I turn it off, and turn just the ignition back on and listen, I do hear one single thump (a different thump) which is the fuel pump engaging, I guess. But all else is quiet. When I start the engine, the repetitive thumping is still there. Last night it wasn't very loud.

[Francesco]

Actually I don't think my car has ABS. And yes, if I turn it off, and turn just the ignition back on and listen, I do hear one single thump (a different thump) which is the fuel pump engaging, I guess. But all else is quiet. When I start the engine, the repetitive thumping is still there. Last night it wasn't very loud.

Is it only at idle or any RPM? If the sound goes away when the RPM are increased then I would suspect the exhaust system hitting something in back when the engine idles.

Frank