Do you have manual glow plugs or still have the factory controller?
If you've still got the factory controller, kiss your glow plugs goodbye. And to top it off, if you dont have Beru plugs more that likely they are all swollen.
If you have them manually wired, and have the controller disconnected then you're fine, but the system is detecting a cold reading since the controller is disconnected, so the system is trying to turn the GP's on.