The computers control everything in the engines now. The injectors are no longer mechanical or pump timed, they are piezo-electric and the computer tells it how much and how long to emit fuel. Stacking is no longer much of a problem with the new systems and they (the manufacturers) recommend no warmup or no idle down to shutoff. Diesel engines at low idle tend to cool below desirable operating temps so they program in a high idle at 1200 rpm and a pto idle at 1500 rpm. The high idle will keep the temperature high enough to circulate oil as needed.
Turn on the cruise control, hit 'set' for high idle. 'resume' for pto idle.
Diesel engines wear the most when starting them up. The seconds after startup when there is no oil pressure can starve bearings and cause premature wear. That is precisely why leaving the engine running when stopped for short periods is recommended and using high idle.
