I have a crank but no start on my LB7 when sitting overnight with temps below about 45F. I have a lift pump and the plunger on the filter head is hard with the key on. Injectors and CP3 have about 200 miles on them (did them myself so no shop to go complain to). Its a CA truck so a single glow plug going out will throw a code - no codes (but I have read where these should start in temps well below 45F without the glow plugs working). Batteries are newer and it cranks fine and starts no problem in warmer weather. All the threads I have read go towards losing prime, bad glow plugs, weak batteries, or even bad injectors but I think I have all of those covered - typically the threads that aren't priming related just fade away without a firm solution I haven't tried the block heater yet - but 45F? Really? I had no starts in cold weather before the lift pump but didn't know about the loosing prime thing until fairly recently so I may have been able to start it back then with pumping the plunger but honestly don't remember if I did that more than once. When it wouldn't start in the past I'd be going to work and just take my car without screwing around with it and it would start right up when I got home.