Pantless Spency

so basically two years ago my parents bought a 77' 240d from some old dude who fixes them up, they decided to give it to me as my first car. we had it running on veggie oil with a secondary fuel filter added and a heat exchanger running off the rad. as well. we ran it on veggie oil a lot and sometimes on diesel, it worked out pretty good. the fuel gauge was bad (figures lol) so i usually calculated mileage so i wouldn't run out of fuel. suddenly after one winter i ran out of fuel very early into a full tank, around 150 miles instead of the usual 250 miles a tank, i had no idea why thought someone may have stole fuel from me. i later figured it must have been some solidized or frozen veggie oil. i had ran out of gas before so i just manually pumped the air out of the fuel lines like normal, i have done this however even with a fully charged battery it doesn't want to ignite. i'm not sure whats wrong with the car but i love it, my parent's want me to get rid of it as its been in the driveway for a long time since i can't figure out the issue. i was thinking maybe the fuel pump went bad and the gas tank is clogged? or maybe the injectors are shot from the veggie oil being to thick, do you guys have the slightest clue what may be going on? please respond soon thanks for the help.


i'm new here i'll post some pictures of my w123 and my e30 as well.
thanks for the help in advance.

Outre

Pumping with the Hand Primer only bleeds the Air out of the Fuel Supply system.

You most likely have Air trapped in the Fuel Injection Lines between the Fuel Injection Pump and the Injectors. (When Air trapped in that area it compresses a lot and moves only a minute amount.)

Loosen all of the Fuel Injection Line Nuts at the Injectors and crank until you get Fuel coming out of all of them. Tighten the Nuts and attempt to start.

The other end of the no starting issues is the Glow Plug System. If you have the stock setup on your car when one Glow Plug goes bad they all stop working.

In the long run Veggie Oil use cloggs things up and because it is thicker stresses the Fuel Injection Pump.