What was found
AFTER TAKEOFF AND ABOUT 4000 FT, THE FUEL FILTER BLOCKAGE EICAS MSG CAME ON ASSOCIATED WITH LEFT ENGINE. CREW DECLARED AN EMERGENCY AND RETURNED TO IAD. LANDED WITHOUT INCIDENT. THIS ENG HAS EXPERIENCED 2 INSTANCES OF FUEL FILTER STATUS MSG. THE FUEL FILTER DIFF PRESSURE SWITCH WAS REPLACED ON 12OCT AND THE MSG REOCCURRED ON 14OCT. THE FILTERWAS CKD, NO CONTAMINATION WAS FOUND, AND THE FILTER WAS REPLACED. ACCOMPLISHED WIRE CKS. REPLACED CONNECTOR (DS73001) AT SWITCH (S73001) AND FOUND SHIELDING DAMAGED. REPAIRED SHIELDING.