Glow plug timing?

Hi, i have a ford focus 1.8 tdci 03 plate. Shes done 156000 miles. Ive changed my glow plugs and used bosch ones. However she wont start very well in the cold. She will crank for over 1-2 minutes sometimes efore she will start. The battery is good. However the glow plugs only stay on for around 2 seconds. Ive unpluged what i believe to be the temperature sensor, that may be giving the ecu a fase reading. However when it is unplugged, the engine still wont start well. So the glow plugs are working any longer with the sensor unpluged. Is there a seperate rely for the glowplug timing. I know there is a rely in the fuse box and ive changed that. But id there a timing rely in the engine bay?