no start cold extended cranking warm

i have an 03 cummins that wont start cold if you pull start it it will start, once it is warm it will start but it cranks for 5 secs before firing up,pre heat works fine any ideas would be greatly apreciated. lift pump is working fine also.:banghead:

Does your model have a plug in?To keep the block warm over the cold nights.I found mine and makes a real big differance.Passenger side lift hood wire is in a loomplug it in and it works.

yes there is a block heater, still doesent start. thks

Does your model have a plug in?To keep the block warm over the cold nights.I found mine and makes a real big differance.Passenger side lift hood wire is in a loomplug it in and it works. yes it has a working block heater. thks:)