Nissan Xtrail

Good morning I have a problem with a Nissan Xtrail truck as a YD 25 CDRI engine which has been fully repaired and the injection system has been done, well, the problem is that it takes to turn on and when the engine is cold it is unstable in the minimum as point of knitting and when it heats it works normal I wait for your comments

Hello, we are ability to a diesel vehicle, if you are sure that the injectors spray well. And the distribution synchronized is correct, it occurs to me that the temperature sensor may not be working properly.
The vehicle is guided in the Tenperature sensor to know if it is cold inject more or less and if it is hot rectify mixture. There would also be the camshaft or crankshaft arblo position that if it does not go well, it can be telling you that it injected late or before time and when the vehicle is heated rounded.
To check the temperature normally measure resistance with the cable removed at more temperature plus resistance. Search the table of that sensor and put you equivalence omios temperature. You already tell us something.