So it took a while, but I finally got around to installing the fuel line return kit and WOOOOOOO HOOOOOOOO!!! Fired right up! Got a couple of questions though. It runs fine on diesel. When I hit the switch to go to veggie it died. I could see the veggie lines full of air, so I kinda assumed that I had just gotten a bunch of air in the veggie side during all my diagnostics. I switched back to diesel, cracked and bled all the fuel lines at the engine, and just like I thought, fired right up on diesel. Now here are my questions:

1) I can see a bunch of tiny bubbles (looks like white foam) in the return lines, starting after the kit I installed. After shutting down and letting it sit, the bubbles settle and the lines are full of fuel (no apparent bubbles). I have my system set up to have a purge mode that will cause it to run on diesel and route the return fuel back through the veggie system to backflush the veggie system before shutting down. I'm hoping the bubbles are just air in the return lines from my replacing them, and I can just run it on purge, flush it back to the veggie tank, and everything will settle out. Does this make sense to anybody or does it sound like I still have a small leak somewhere in the return system? I'm tired of dying and bleeding to restart!

2) When I put the replacement fuel return kit in I pushed the little plastic caps down as far as they could go. Most of them felt like a little, "click," into place which I assume was the o-ring seating in the groove inside the plastic cap. However, now each cap has about a 1/16" gap between the top of the cap and the metal nut that holds the fuel line on. Before I took the old caps off, most of the caps were flush with the metal nuts, except for one (which had the same 1/16" gap as all of the current caps). I'm not sure which is correct. Did I push the caps down too far? Could this be the cause of the bubbles in the return?

I could figure this out on my own, but I've been working on this for so long that the idea of another session of trial and error is unapealling. I'm hoping someone might have some guidance.

3) Finally, do I need to replace the lines that came in the return kit with some other material to run veggie?

Hope someone is still listening!
Thanks!