Bad Fuel Pump or Fuel Filter? (Video)

[DylanFulton]

I get this grinding/clunking noise coming from the back seat near the fuel pump. This only happens on cold starts when it's below 10°c, typically only the very first start of the day or if the car has been sitting for an extended period of time. I'm unsure if the previous owner has changed the pump/filters so for the sake of this I'm going to assume they're original. The audio quality in the video wasn't what I'd hoped for but you should be able to get the idea...




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[Cinna696]

Between your keys and the music I have no idea what noise you are talking about. In the future keep the microphone as close to the believed source and turn off the music...

From your description, it could be the evap system in the fuel tank - this is known to cause a bubbling/belching noise and traditionally has no real fix unless it's related to the charcoal canister. Google this stuff and see if it relates to your noise.

The fuel pump primes as soon as you put they key to the on position so you would hear it then if it was acting up.


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[VinnysS4]

Between your keys and the music I have no idea what noise you are talking about. In the future keep the microphone as close to the believed source and turn off the music...

From your description, it could be the evap system in the fuel tank - this is known to cause a bubbling/belching noise and traditionally has no real fix unless it's related to the charcoal canister. Google this stuff and see if it relates to your noise.

The fuel pump primes as soon as you put they key to the on position so you would hear it then if it was acting up.


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Agreed. Cannot hear a thing. Have someone else start the car and you sit in the back seat near the source

[DylanFulton]

Didn't have anyone to hold the camera for me so I had to get creative. You get a much better idea of the sound now. You can hear the pump prime immediately followed by the noise.




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[Cinna696]

Now that is a noise! I've never had that one to be honest, but the only part near there that moves is the fuel pump. It's located under the seat so I would remove that and confirm the noise is coming from the fuel tank.

Does your car have no/little fuel in it? As in, does it make this noise even with a full tank?

It's also possible since this happens at low temperatures you might have excessive water in the tank.

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[VinnysS4]

Yeah...probably the fuel pump. I don't think a filter would make that noise but I could be wrong lol can't think of anything else it could be...electronic parking brake?

[DylanFulton]

I had about a quarter tank at that time, but it'll make the noise at any level it seems. As I said in my original post, I don't know if the filters have ever been changed so I'm going to assume they're original. I was thinking a potentially clogged filter could cause the pump to back up and make that noise as the debris would get more dense as the temperature drops. Not sure if that's actually the case but it makes sense to me, worst case scenario it's the pump.


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[Cinna696]

I know you're hopeful it's something cheap like a fuel filter, but you'd be undeterminably lucky.

Pull the rear seat up, repeat the procedure and isolate the noise to the fuel pump. Then replace it, pretty easy these days - could do it yourself.


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[teutoned]

fuel filter: about $60 on the high side, has internal pressure regulator, is a regular maintenance item which you think is OE, takes no more than 30 mins to replace, if its restricted the fuel pump has to work harder.

fuel pump: costs $300- $400, requires way more than 30 mins to replace, should replace filter at same time, and typically fails because filter was/is restricted.

replace fuel filter.

[hkdolphins]

I love my S4 but i dont know much about car, just share what i experienced 9 months ago with similar sound.

My bro borrowed my car, low engine oil light on and he went to a friend shop, oil change with premium price but shit oil used(not typical branded one). When i had the car back 800 miles after oil changed, this sound happened 3 mornings in a row with cold start around 30C. I didn't know what the reason, so i didn't drive it. I took it to oil change at local dealer and thats sound gone right away. I also changed the fuel filter at 1K miles after and didn't hear that sound anymore.

[DylanFulton]

Update: I changed my filter on Wednesday, I figured it was worth a shot before shelling out for a new pump. After driving the car everyday with the same sort of conditions to produce the noise; I haven't heard it once. Also, my pump seems to be significantly quieter when it primes now. I've attached a picture of how dirty the fuel that came out of the filter was. I figure either way it was probably best it was changed anyway.




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[xhackerekx]

my fuel pump start made exactly sound like yours after fuel filter change.

[jakeoboy67]

eww that is nasty stuff