noise.....not JHM exhaust noise. Under hood noise

A5/S5/RS5
#1

???

For a while now I’ve had a sort of rhythmic, scrolling, comes and goes rubbing noise from under the hood. A mechanic who had a quick listen one time said likely a fuel pump as they’re mechanical. I’m at 78,000 miles. Lately it’s getting more routine so maybe I should address.

2010 4.2 V8

So - are there any upgraded or “better” fuel pumps to consider in my quest to make this car faster? Or is a fuel pump not a potential performance mod.

Thanks.

#2

Does anyone know if the fuel pumps are the same on the S5 and RS4? JHM sells an upgraded rebuild kit for the RS4 I believe, so you may want to contact them.

#3

or maybe be sure it’s a fuel pump before buying stuff…

#4

I would be willing to bet that it is the PCV valve. Clean off the area around the oil filler cap, start the engine, let it idle, and try opening the oil filler cap. The cap should come really easy like if the engine is off. The engine should stumble and then smooth out. If it stalls then your PCV valve is bad.

#5

Ours went bad on our B8 A4 last month.

#6

What were the symptoms? The noise I’m describing?

#7

I tried that test. Thank you buddy. I let the motor settle into its warmed up idle. I didn’t hear the offensive sound. I removed the cap. The motor sputtered and sputtered and the noise showed up in force. So that must be it. It didn’t stall but it sure didn’t smooth out until I replaced the cap.

#8

I know it might be a lot of work but maybe try to video the noise when you pull the cap off and then once you replace the PCV do the same video. From there maybe start a thread on noisy PCV systems and what they sound like. You could even go a step further and pull the PCV apart and see what the issue is.

Good suggestion jimmy… as always

#9

I got footage of the sound. It’s quite apparent so I don’t think there’s need for before after.

#10

justin is one of the smartest guys on any audi forum on earth. If he offers to help you’ve lucked out. If he asks for something, give him it. No offense but what you think (or I for that matter) don’t really matter much with stuff like this. So get him a before and after.

#11

Plus one- I think before and after might help to establish what is or isn’t needing repair.