The oil line to the fuel injection pump is to supply lubrication the pump, not to pump (motor) oil into the engine.
A quart every 2,500-3,000 miles is not bad consumption.
Why not change the oil and filter when it is down 1 quart, rather than add a quart for a short time?
'96 E300D 60k mi (wife's daily ride)
'95 Audi 90 120k mi
'92 GMC Suburban 139k mi
'85 300SD 234k mi (my daily ride)