RV: humming fuel pump

[jmargari@ibermatica.es (J. Joaquin Margarido Menendez)]

I have the same problem whith my 88 Audi-100 Quattro. I don't know where is de solution but 
yesterday I found in Internet this text:

http://www.teleport.com/~scottmo/index.html

FUEL TANK COATING
The protective coating inside the fuel tank can come loose and clog up the mesh screen at the bottom of the fuel pump causing poor running or fuel pump noise. According to Audi service bulletins, the later vehicles do NOT use this coating anymore, the cutoff for the early vehicles is up to 1990 100 AND 200 Cars at VIN # 44KN017651. If you have a vehicle made BEFORE this cutoff date, the service bulletin describes a procedure for removing the fuel pump from the tank and cutting out the mesh screen from the bottom of the fuel pump to prevent future clogging. 

FUEL PUMP NOISE, REPLACEMENT
Here is what I know about fuel pump replacement on the 84-88 5000 Turbo/Turbo Quattro and 1989-90 200TQ series cars. 

NOTE: I do not recommend that you attempt to do this with more than 1/8 of a tank of gas. 
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