I think you might have injector issues, this is going to suck but hear me out.
Last July I purchased my dodge, 03 CTD blah blah blah. Fast forward to January and we were having some colder weather (freezing to mid 40s), my truck would take a long time to start. Take a video of your truck when it is cranking cold and we can see how long it is, I thought mine was cranking for a long time and it was only 5 seconds or so. Which is still way to long for a CTD.
Now we checked my pressure and it was only putting out something like 8psi from the lift pump so we decided I would just replace it with a FASS because it had the better filtration system. The factory filtration system that dodge puts on the truck is somewhere in the 10 micron level I believe, the injectors built by bosch don't like that, they want much cleaner fuel and this has caused many injector problems for the trucks when you get more miles on them. So you can buy a FASS that has a 3 micron fuel filter on it and get much cleaner fuel to your rig. One more thing about the trucks and the FASS is don't use the draw straw, or if you do don't ever go below 1/4 tank. We ended up picking up a sending unit from Chrysler that has no pump in it, essentially the one that would come in the truck originally when the pump was located on the firewall. This lets you use a factory fuel pickup and you can run the tank down much further.
Ok so we put the FASS and finally got everything sealed and working properly the day before I drove 1300 miles to the hammers. We had to take a dremel to the sending unit and take off about a MM around the edge to make it fit but that wasn't a problem once we figured out what we needed to do. Anyways loaded the truck up and drove to KOH, everything was fine and dandy till I went to move the truck friday morning and it wouldn't start, cranking for 10 seconds at a time and nothing. Well I guess it wasn't just my lift pump that was bad. So the next day when we were getting ready to leave I plugged the truck into a generator and warmed the motor up before we left and it started up alot easier.
Once I got back I started checking around more and more and this was very common for the common rail CTD. The injectors fail because of the pressure and since you are running a pressure box on the truck (any edge type of programmer relies on increased pressure to the fuel rail) you run the risk of damaging your injectors even more. When I went to purchase my injectors it took me a couple of months to get them because they were nationally back ordered. Bosch recently moved their production from Germany to Brazil and the time it takes to fill an order of injectors increased, plus they are still making the injectors for the new trucks coming out so that is their first priority.
When I picked mine up we went with 50hp nozzles on them because it was only a few hundred extra $$ so why not, the total bill on the parts was around $2400, plus the FASS I had installed earlier in the winter.
Short notes:
-If its cold out and the truck wont start easily it is probably injectors
-Edge is bad for injectors
-Injectors are expensive
-Good luck.
-Alex