I'll be listening. Haynes did an excellent job on the manual for 617 engine. But I guess the information has been kept from them as well or the reward of preparing a manual to cover the 603 is not worth the effort in terms of reward on investment that it would take to produce a good quality book covering the vehicle in such great detail, as they did on the 617. And I believe that the 603 engine operates and was built on the same principles as any diesel engine, especially the 617. The concept of compression, fuel and air and the engine should run is basic in all diesels. Even if the engine didn't start, the fuel should pump. And on the 603 injection pump, the degree in which you tighten or loosen the injector seal holder, you know, the cap in which the fuel line enters the injection pump, will vary how much fuel is pumped out of the injection pump. But this aspect is not the same on the 617 pump, which is rigidly tight. Which brings me to, should the cap or seal holder be as tight on the 603 pump as it is on the 617. Areas like this is where the information is rare. Nobody seems to know the intricate operating functions as to what is "supposed" to happen. I will look forward to hearing what you can find out. Old300D suggested it could be the manuel fuel pump, but as I understand it, that pump is supposed to pull the fuel to the injection pump; and it does that and once the fuel reaches the injection pump, somehow the fuel is pumped with pressure. I've checked to make sure all lines are tight with no leaks, especially the plastic fuel line from the pump to the fuel filter area and the small things like that. Is there some electrical component that activates the injection pump pressure? These are the answers that I'm seeking. Diesels are supposed to be "simple".

BenzDiesel