Well, this is a new Bosch main fuel pump. It took me three attempts to get all the connections leak free. The last leak was at check valve because it had loosened during counter holding with wrench to put on bridge connector between the pump and filter.

At that time the pump was louder because of leak at check-valve. Now it's a very high pitched sound that only happens when at idle, disappears with gas pedal, but appears when moving without gas, "gliding", coasting if you will. I swear this sound wasn't there earlier when I first installed pump.

I will double-check fuse is in snug since it was in-and-out mutliple times over three-days to depressure the fuel line.

I'm thinking there is a weak spot in the system that is making the pump whine. What remains? The FPR? I will try to swap it out this weekend. I do not smell any other leaks in the hose system. In-tank pump is new, Airtex.

Any suggestions?
--
I own a Volvo or Does Volvo Own Me? Try the easy to search Expanded Style FAQ Index http://40mph.com/Brickboard_700-900_FAQ_Expanded_Index_Version/