2000 Freightliner Classic 500hp Detroit won't start without ether

So a friend's 1.3 million mile 2000 Freightliner Classic with the 500hp Series 60 Detroit will not start on a 65 degree morning without ether. Once started it runs and starts fine the whole day. We put a new lift pump on it since the old one was showing leaks, and that seemed to fix it for a few days but now it won't start without ether once again. I haven't checked compression yet, but is it more likely to be a compression issue or a fuel related issue? And how would I go about checking fuel related diagnostics?

 

And if this should be moved to a different thread feel free to move it, whoever is in possession of such power.

 

Ahh... That's a lot like my 7.3 Powerstroke. Maybe I'll bring it to a professional who has proper software.

 

This would seem to be more likely thr probem as an injector was replaced earlier this year. I will have to get the truck in the shop once we get his other truck to start (N14 ran out of fuel and starter crapped out at the same time)

 

Haven't tried anything yet, but guessing from how it starts fine once warm I'm banking on a leak around the injectors, as one was recently replaced. I'll be driving it up by Crookston MN tomorrow so I'll do some diagnostics then. I'll be sure to update tomorrow!