I think I remember this one, its a veggie burner....owner had a 2 tank system but used the main tank as the veggie one.....he gunked up the system and can't get it to start....the factory lift pump wasn't connected.....he said he is just going to buy another wagon and do it over again.....can't remember where the thread is....
Dunno if it is or not but here's the thread
http://www.peachparts.com/shopforum/diesel-discussion/338869-fuel-issues-300td-w123.html
If its not, I would suggest it has a bad IP due to incorrect wvo use.....so tread with caution....