I've had my 2003 2.0 Zafira diesel now since april 2009 but always had problems starting it when weather is cold. Lots of cranking a cough a splutter and a ploom of white smoke. It's had injector seal changed and checked, its had fuel filter done twice, spill off pipes have been done, compression tested (all ok), diagnostics been done (shows nothing), glow plugs have been changed twice and tested, glow plug control unit tested (all ok), temp sensor changed and tested. I'm out of idea's now and hoping someone can suggest something else. I'm wondering weather could be fuel pump ECU????

Help Me Please!!!!