Except for the bad heat treat problems, what causes the injection problems?
Water in fuel? Dirt in the 7 micron range? Poor lubricity as a side effect from sulfur removal? Teething problems with design of higher pressure systems? Too much time spent parked and shut off? Something the armchair internet experts haven't heard of yet?
Exactly what can I do to head off problems? I am cautious, tight with a buck, and a lousy mechanic.
I don't think anyone can state the cause with certainty, but ...
Between 2005 and 2008 Kioti changed the engine design (at different times for different models) from an external shutoff solenoid (on right side of engine) to an internal setup with the solenoid on the front of the block. It seems this new solenoid was too forceful for the original control sleeve design and teeth would break off that part after several hundred hours of operation. More likely it was after so many engine stop cycles, rather than operating hours. Tractors with the original, external stop solenoid were not vulnerable. Tractors after about 2009, apparently, have an upgraded control sleeve and are not vulnerable. Some of the replacement injection pumps also had the old part design and failed after installation.
To answer your question, I don't think there is anything you can do (assuming you are even effected) other that avoiding unnecessary engine stop cycles; but there can be safety problems with that.
According to Kioti the only fix is a whole new injection pump, costing $1000 and up. But we now know that this is a common Zexel (formerly Bosch) agricultural injection pump and parts are readily available for repairing it. Even better, control sleeve replacement does not require special tools or re-calibration, if done right.
thepumpguysc, on this list, is one of the experts on these IPs.
There are other possible IP failures but the fix for broken control sleeves (new control sleeves) is relatively cheap (like $50-200) and easy.
Replacing the control sleeves in the IP only takes 20 minutes or so but requires strict cleanliness and meticulous attention to detail.
Removing and reinstalling the IP (same job with new or rebuilt IP) takes considerably longer. A handy DIY owner can do this job but several factors can make injection pump removal/replacement quite challenging, such as: the tractor breaking down in the middle of nowhere, or breaking down in an inaccessible location (like too close to a wall), or being unable to remove the loader, or being unable to remove or to fully raise and secure the hood.
The replacement control sleeves I received from Conestoga Diesel were slightly different from the original ones so I assume they are upgraded parts and will be tougher than the original ones (one of which failed).