I have a 2004 Freightliner Columbian with a 60 series Detroit here at the shop that will not start unless you run it on ether. A little history...the engine was rebuilt about 6 yrs ago. The truck sat up for a few years before the owner decided to repair the truck and put it on the road. While letting the truck run to build up air pressure so the D.O.T. inspection could be done the truck died and would not start. The owner assumed the computer so he had it towed to the shop here and brought the computer with it. After checking the truck with the scanner we found that the ecm was bad. Installed the new ecm, replaced the trs and the srs sensors just to be on the safe side. checked the power and grounds to the ecm, checked battery connections and check for broken wires by using a headlight as a test light, and also checked the water and oil levels. all checked good. The Truck still will not start unless you use ether and shuts off as soon as the ether is gone. We also checked the fuses, wires, and connections to the ecm and the back of the head. The scanner shows that everything is working properly with no trouble codes. Any and All suggestions will be appreciated.

sounds more like a fuel (or lack of) problem to me, have you checked that there is fuel in the tank? Is fuel getting to the filter? After sitting for "few years " it could be contaminated with algae. If you've never seen the stuff it's pretty disgusting looking and will clog a filter REAL quick. I had a plastic 5 gal can full of D2 that got contaminated and the stuff actually attached to the sides of the can and grew a ring that kinda resembled seaweed.
I'd start with a new fuel filter and siphon some out of the tank into a clear container and look at it. If that doesn't do it then I'm not sure but there are some valves under the cab between the tanks that could cause a no fuel issue. Other than that I got nothing!

I agree. It sounds like it isn't getting fuel. If you have fuel in the tanks, you might start by changing your fuel filters. It may also be a fuel pump problem. I would first start with the filters, it is much cheaper. I had a friend who had algae in his fuel. He had a difficult time getting rid of it, but when he did the truck ran fine. His filers kept getting clogged until he killed the algae.