Schematic of Cold Start Circuit

[buickanddeere]

Diesel's have higher combustion chamber temperatures and higher EGT with advanced timing. Gassers run hotter with retarded ignition timing. The thermistor heats up and reduces current supplied to the injection pump which retards the timing advance to reduce NOX stack emissions. When jumpering out the resistor so the injection pump to obtain full advance when warmed up. Cold starting will be improved. cold driveability improved and reduction of cold operation exhaust "smoke" occur with advanced timing.
As for cold weather starting. Plug in the block heater and hold the clutch down while cranking.