Hi, managed to trace your original Q, the glow-plug timing is not dependant on Air temp as was originally stated it is based on the on your engine cylinder head temp, that is fed to the ecu to determine the duration of the glowplugs on heat timing and affects the pump fueling amounts (like putting the choke on an old petrol car) if the sensor is telling the ecu the engine is warm/hot it will only put the power to the glowplugs for a few seconds and set the injector pump fueling for a warm/hot start, hence your cold start problems.
nige110162(at)hotmail.co.uk
nigel, December 2009