I've been tracking down a "buzz" that's comming from the main fuel pump area for weeks now in my '82 k-jet. I've checked all the usual suspects - relay, in-tank pump, clogged filters, clogged lines, etc. - and I've also tried three different main pumps - two used, one "new" remanufactured Bosch - and I still have a noise, though granted, not quite as loud as before.

This last go round - man I'm getting sick of putting that damn pump mount plate back on only to take it off again - it was quiet! Yes, I could still hear the noise a bit, but that's totally normal, the point is I could no longer hear the pump from ten feet away above the sound of the exhaust and engine...for about 5 minutes. Then the noise slowly came back, and while still not COMPLETELY as loud as before, it's getting annoying again.

SO I ask myself, "What did I do different this time that made it quiet for about 5 minutes?" And I answered myself, "Well, I unscrewed the accumulator plug screw and squirted in some WD-40 just to clean out any crud or rust that may have been inside." Hmm.

I got back under the car and started poking around while the car ran and with this new knowledge, paid special attention to the accumulator. It seems to me that the accumulator is vibrating FAR more than the pump.

I know the accumulator diaphram is ok, no fuel leaks out the back while the car is running. And the car still runs fine.

Has anyone else ever heard of an accumulator making noise through vibration?

Is it possible, defying all Volvo wisdom concerning buzzing noises from around the fuel pump, that my noise problem is actually a crusty old accumulator?

Is it possible that a stuck accumulator is causing the pump to work harder and that the main pump is still making the noise?

Further, is the accumulator REALLLLY necessary to the operation of a k-jet?

Finally, I have a much larger accumulator from a turbo 242, is there any reason that this one could not be used on a naturally aspirated model?

Thank you, for ANY advice you might be able to give. I've exhausted my line of troubleshooting thus far, I need some fresh ideas.

EDIT: I'm willing to accept that the pump may just be transferring vibration to the accumulator, in which case, what are some other reasons the pump might buzz, besides the usual in-tank stuff? Could cheap, dry gasoline be causing the pump to make noise for lack of lubrication?