Cammed 6.2L Warm Start Issue

[ocdiesel]

Stock Long Block with TSP Cam 220/230 .615 .615 113, Cold start and hot start is perfect. Trouble I'm having is when the vehicle sits and cools off for about an hour the warm start is horrible and cranks over quite a bit before it catches and starts. I've been up and down with the Cranking VE, Cranking FA Mult Stage 1 vs. Cranking Time, Timing adjustments etc. Can't seem to make it start up well after it heat soaks. File attached and If anything I can dropbox a link to the start up video. I've monitored Lambda on start up and it dips a little rich and seems to do so no matter what I do but also doesn't seem to make a difference what way I go on some of the tables.

[blindsquirrel]

Fuel pressure with a mechanical gauge at the rail when it won't start, compared to rail pressure when it starts OK?

[brewster]

I posted from my business account and am replying from my personal account. Yea might be best to check the fuel pressure and see if its bleeding down, I thought the pump primes at key cycle on but I don't hear anything fuel pump wise. I also read that the pump doesn't start to prime until you actually crank the engine over. Starts great after sitting over night, and starts great when hot after shutting down for 10 min or so.

[brewster]

Here is a dropbox link to the video of it starting up after sitting for about 45min. Ect sitting around 125 deg F

https://www.dropbox.com/s/lqjnm4wuhc...905_n.mp4?dl=0

[blindsquirrel]

I've more often seen pressure rise during a hot soak causing crank-no-start. Fine when cold, takes a little while to start rising when shut off hot, spikes too high at the middle/end of a hot soak, back to fine when it cools off. High pressure can lock injectors closed and no amount of pulsewidth you command in the tune will open them.

[brewster]

Hmmm, I mean I can def see the pressure rise on a hot soak. Just with it being winter up here atm I can't see the rails getting that much heat from the engine. These injectors were also tested / flowed a few months back when we did some other work and they were in perfect working order. I figured maybe this has something to do with the Cam in it and the VE.

[blindsquirrel]

I figured maybe this has something to do with the Cam in it and the VE.

Sure, it might. But a lot of diagnostics is checking stuff that can't be checked any other way, so you can then definitely rule those things out as potential causes. (hoofbeats something zebras something horses etc.)

What would you (or anybody) be able to do in the tune to rule out a fuel system problem? Try everything?

[brewster]

Yup, makes sense to me. I guess I just know this truck so well as we have been putzing around off and on with it for the past couple years and haven't had any issues with the engine starting and catching. Runs great other wise, and can't see any issues logging it either. Even had the wideband wired into 12v hot and monitored it on start up and looks fairly normal from what I would know. I'll stick a pressure gauge on it and get some more data that way.