A3 - loud vibration
 

hi all,

i have an a3 61 sportback 1.4 tfsi.

its done 30k miles. I've noticed over the past 3 months that my car has inconsistently been making loud vibrating noises, which has got progressively worse.

Upon on further inspection after lifting my back seat, the fuel pump is the culprit and is causing a very loud vibration and an annoying noise.

fuehermore, when I start the car the revs counter sticks just over 1.5k revs and it feels as though I'm losing power.

anyone experienced the same and does anyone have any idea if the two issues are linked?

thanks in advance.

Not familiar with he 1.4 as they never sold that one in the states. However I've heard from several sources that the Fuel pump and Fuel filter can hum or vibrate loudly when clogged or when they start to fail.
If you can hear it while stationary go to the fuel tank cap, lay down on the ground and put your ear next/under to the rear door (just don't let the car roll over you!). If you can hear it clearly that's the fuel filter. It's an easy and cost effective replacement. Unfortunately if that's your issue I would start looking at the fuel pump as well. It could have been under increased stress from the clogged/failed fuel filter and therefore worn out. I would play it safe and replace both if you can clearly hear it from the pump/filter area.

Thank you for the response.

I've taken theback seat off and got my friend to push the accelerator to around 2.5k revs and put my hand on the fuel pump and it stop when I put my hand firmly on it.

Would you expect the loss of power to be completely linked to this as well? I've been told it could be the constant use of the air con taking some power away from the engine once it's left on and the engine starts.

Thanks.

If the Fuel pump is the cause - absolutely. I've had my fuel pump start going bad on my 2007 A3 (2.0t engine) and I had complete power loss when driving up a hill or going over 4k RPM (the engine never turned off though). So a bad / faulty fuel pump can cause incorrect fuel pressure and therefore reduce power output to a point where the car could stall or just not accelerate.
Replacing the fuel pump is pretty easy (though smelly) so if you feel comfortable turning a wrench do it yourself and save the labor costs. Make sure you replace the fuel filter while you are at it (sits below the tank on the rear bottom side where the fuel lines run from the tank to the engine (at least where it was on my 2.0t).

If you have access to a VAG-COM you can scan the car for fuel pressure (if your car is equipped with a fuel pressure sensor). You can also scan the car for additional fault codes to see if there might be more than 1 problem you are facing. If you don't have the scan tool - start with the obvious.