Be careful when buying a diesel truck that someone has ran out of gas. i was reading today what could happen. and what i read was you can lose injectors due to loss of pressure in the fuel system. with bad injectors the truck will not start. this is what i read, i know its for a 6.0 motor but it can have the same effect on an HEUI (HEUI stands for hydraulic electronic unit injection) system.
"Also, because the fuel actually provides a cushion for the internal valving of the injector, anything that causes low fuel pressure will kill the injectors. This includes not observing proper fuel filter maintenance. We recommend that fuel filters be serviced at 15,000 mile intervals. Low pressure caused by a failing fuel pump can cause repeat injector failure. ALWAYS check fuel pressure after installing new injectors - it should be between 45 and 55 PSI and should not drop below this spec under load. Finally, running a 6.0L Powerstroke out of fuel is deadly to injectors! On early trucks, if you run out of fuel, you will usually be buying 8 injectors. If you think you are going to run out of fuel, stop, shut the truck off, and walk. It may save you $2,500. Later trucks have a PCM strategy which limits pressure to prevent injector damage during a low fuel condition, but it is still a situation to be avoided at all costs"