Sorry i am really lazy and didn't read every post.
I had a "no hot start" dilema and the issue was slightly fixed by running my glow plugs on a relay&switch but the real issue was that there was no compression what so ever. My head had huge cracks in it and likely lots of other problems.
The coolant T at the head has a temp sensor that, when hot, tells the glow plug relay not to cycle and therefore you dont have glow plugs but that being said shouldn't it start fine then if those are normal parameters?
I would do a compression test. And if it comes out super low i'd take the head off and check it thoughrally. Possibly change the rings too while you're there. Rod Bearings and rings are a very easy job if you MARK EVERYTHING so they don't get mixed up and already have the head off.
