Grinding, " diesel " noise under valve covers

It's not the valvetrain.
Just got back from a Friend's place. Borrowed a stethoscope and a endoscopic gimmick w/ a side scope. Gonna warm her up and listen after pump goes back on. Getting dark though. May get some lights.. did the screwdriver in timing cover, all is tight there.. except fuel pump. Now I'm second guessing myself. Was the fuel pump the noise? And I'm a hearing rockers rubbing now? Or did nothing change?