77 240d manual with 128K.

Wife drove car into garage, ran good. next day wouldn't start.

changed primary and secondary filters. Only 3000 miles on them.
fuel is car ran good before this happened.

go to start it the next day and glow plugs stayed on longer than normal (not a cold day either). Engine cranked normally. No smoke, sounds like not getting fuel--obviously.

My question is, what controls fuel supply shut off? mechanical or vacuum. Is there a way to bypass.

what shuts the pump off? mechanical or vacuum?
Is there an aluminum colored box under the dash that controls the shut off? Vehicle does have the manual red shutoff lever.