A method of operating a compression ignition engine, which includes at least one combustion chamber containing a piston, and a mechanically operated fuel injection pump apparatus. The method includes sensing the engine operating temperature with a first sensor, and providing input to a controller. The controller operates the fuel injection pump apparatus to deliver fuel to each of the combustion chambers according to a first timing regime when the engine operating temperature is above a threshold temperature, and according to a second, advanced timing, regime when the engine operating temperature is below the threshold temperature. The method further includes sensing the pressure in the combustion chambers with a second sensor. When the controller is operating the fuel injection pump apparatus according to the second timing regime and the combustion chamber pressure exceeds a desired pressure, the method includes changing operation from the second timing regime to the first timing regime.