Am I correct in thinking my 7.3 farm truck is very forgiving to fuel quality vs my 6.7? Also my tier 4 final tractor that replaced basically an older version I had now has 2 fuel filters(dpf also) and water in fuel warning sensor. My older tractor (2008) it replaced didn't even have a water in fuel warning light, neither does my 2003 Massey. How different are these new fuel systems?

 

completely different animals. about the only thing they have in common is the diesel fuel that goes through the systems.

 

Yes, your 7.3 is much more forgiving when it comes to fuel quality or contamination. It uses high pressure engine oil as hydrolic fluid to bring the fuel to high pressure inside the injectors. It's called a HEUI injection system.

All the modern diesels are common rail fuel systems. Common rails can make bigger power easily, compared to the old fuel systems. The lift pumpcsends low pressure fuel to the cp4 (or cp3 in the cummins and 6.4 powerstroke). The cp4 pressurizes fuel to 25,000+psi and has extremely tight tolerances.
The injectors are also completely different. If just a little bit of dirt or water gets past the fuel filters, it can cause an injector to stick open, which will destroy that cylinder very quick. That issue is the main cause of early death in the 3rd gen dodge cummins. They didn't have sufficient factory fuel filtration.