Cold no start issue when sitting awhile

[D66stroke]

We have a 03 7.3, if the truck sits for a couple days or more, it doesn't want to start. Sometimes it eventually starts, sometimes ether gets it going (I know I know..), and sometimes ether won't even fire it over. Once it starts, it will run fine and start anytime you need it as long as it's within a day or so of it running. So far whenever I plug the Auto Enginuity into it to watch ICP and IPR duty cycle, it fires right up, of course. I did get an ICP code (P1211 I think it was) but I think that was from emptying the oil rails on a hard pull. New parts are HPOP and IPR, ICP sensor, 3 sets of injectors, UVCH's, the list goes on. All OEM parts aside from injectors which are aftermarket. I tested fuel pressure a couple years ago due to another issue and it was within spec, 60+ psi at idle. I'll look at it again to confirm. Any ideas what I may have going on? It also recently got a new oil pan and this issue started happening after that, so I'm hoping it doesn't have something to do with the pickup tube.

[Arisley]

Check the oil level in the HPOP reservoir.

[psduser1]

When mine sits for an extended time, more than a couple weeks, I'll have to crank it over long enough to refill the oil rails. It runs rough for a bit, but smooths out after a bit.
Just a thought.

[D66stroke]

Just checked the HPOP reservoir and it's full after not running for a week or so. Tried to start it and it won't start.

[Arisley]

Check voltage while cranking. Check glow plug circuit.

[D66stroke]

I never thought about watching voltage. It cranks fast though, new starter and newer batteries. It won’t start on 90° days so the glow plug system is kind of out of the equation. It does have a new Western relay on it

[Big Bore]

Did you ever check the fuel pressure? Did you check ICP/IPR when it wouldn't start? GP and relay shouldn't matter in 90* weather. Usually something like you're describing is an injector o-ring problem.

[tomlin]

Keep it simple. This is what I mean by that statement. When you are adding ether you are bypassing the injectors, HPOP, PCM, diesel fuel, oil, all of it. You are feeding ether into a compression ignition engine. It should start and then immediately die every time it gets a squirt. If it will not start and die with ether, your either not getting air or you have a serious low compression issue. You risk blowing the intake or heads off playing with ether with the GP relay connected so be careful with the juice.