My '82 245 with a B21 and K-jet injection has always emitted a sharp buzzing sound from the main fuel pump area under the rear seat. It isn't the pump itself, as this is the second main pump the car has had in the 13 years I've owned it, and the buzz has always been there. It sounds like a metal fuel line vibrating against the underside of the car, but I have checked and checked again, and nothing is vibrating against anything else. The noise goes away sometimes, but it doesn't seem to coincide with anything else (like fuel level); it's random. The in-tank pump was also replaced in the last couple of years, and I'm sure it's working. The filters are new, and the car runs quite well. What could cause this sound? The only thing I can think of is the fuel accumulator next to the main pump, but I've heard that these rarely fail. Any ideas?
Colin