score-o-valves

My 91 200 2v tq avant fuel pump is loud, and gets progressivly louder as you drive the car, after about 2 hours of driving it's so loud the radio barely drowns it out.. Things I've done to no avail: replaced pump, replaced noise damper, checked fuel pressure (it was a little high so I replaced the pressure regulator) changed fuel filter, checked all components of the charcoal canister system/ vent system...out of ideas. Also getting fuel smell in the back of the car after a few hours of driving...the louder the pump, th stronger the smell...but no leaks...I suspect fumes escaping from the tank rather than actual leaks....but what do I know. ? car has about 150K miles...impeccable maintenance...would be nice to fix this. Thank you all.

Black-Wolf

check your vent tube from the tank, it is blocked or otherwise damaged. As you drive pressure builds up in the tank and causes the problem you described. Easy test loosen the gas cap and try driving it.

SmellenDelicious

Curious. Where is this vent tube?

score-o-valves

pull the cap while it was running...expecting to hear the big wooshing sound of the venting action...I did not, nor did the noise change.

Will Ng

See if it's blocked. There should be no restriction to the excess fuel returning to the tank.

score-o-valves

run the car with the return line right out of the (new) pressure regulator into a gas can on the floor, with the intention of eliminating the possiblity of a blocked return line... the symtom remained unchanged. Thanks everyone keep those ideas coming !!

luisen

Hi all !

I have the same issues described in the first post in my AUDI 200 20V year 1990. Did you manage to solve it?

I have carried out all the tests you have recommended and I still have the problem. I find myself lost right now.

In Audi parts catalog can find a FUEL ACCUMULATOR part number 447133441 but I´m not sure if the 200 20V use it or where is it in the car. Is the only part that I have not replaced.

Any help to solve the problem would be greatry appreciated.

Thanks to all !!