#FuelPumpVibration

Paul writes:

Hi Sajeev, I have an opinion/advice question for your column:

I have an ’05 Audi S4 (B7 generation), and this is not a question about this model’s notorious timing chain that so frequently scandalizes car website comment sections.* I have a longstanding issue with fuel pump vibration. It is extremely noisy when it primes, making a rapid clicking or clunking noise that is audible both inside and outside the car. It only lasts for the priming process, and afterwards, the car starts and runs as normal. There is no hesitation in starting, misfiring, or power loss. It is only a noise.

I assumed it was the fuel pump, so I replaced it, but the problem did not go away. I took it to a German car specialist that I’ve used for many years, someone trusted but also somewhat expensive. He confirmed that the pump is not at fault, but suspects that the housing for the pump — which is built into the fuel tank — is broken. There is some kind of vibration dampener assembly that not doing its job and the noise is from the pump rattling the housing around during priming.

Repairing this, according to him, would involve replacement of the entire fuel tank.