I've used this for roughly 30-40 hours now with modified and default settings and it has been very random on whether it wants to work or not, i've also been unable to fully assses the impact of a realistic small connector/transfer capacity because even as im using default settings right now its completely dead in the water.

Gonna have to rebuild some things with normal pipes for now but i sure do hope this is fixed, its a great idea that reduces the arbitrary limitation of vanilla with a system that makes more sense.

What sort of behavior have you been seeing? Details?
Can you post a save I can examine?

Oh hi, sorry for the late response.
When i came back it looked like it was working so i rebuilt the pipes, but as soon as i did it stopped working again.
Here's the save, player is right on top of the relevant objects.
https://drive.google.com/file/d/1-ccyAuZulSQSTqVXuhfZH0hrx9UDOhmg/view?usp=sharing

There's a lubricant line next to the oil line that was deactivated, when i tried using it again it seems that its working perfectly, considering the size of the oil line it might have something to do with the length of the underground pipes.

There's also a gap on the beggining of the oil line but that was done recently when i realized the line wasnt working, however the pipes are still full.

I tried breaking down the oil line into smaller parts to little avail, im noticing it very occasionaly transfers fluids but its probably unrelated to the breaking down of the line.

From the moment i first posted today to the time of this post the tank that is connected to the output connector only filled to 16k

So it looks like your total oil income here is two pumpjacks, one at 2.5/s and one at 2.9/s. 16k / 5.5 is ~2900 seconds, or 50 minutes. It sounds like pipelayer is correctly transferring all the oil you actually have access to. Note that the fact that the underground pipes are full means nothing. Those pipes are only to show you what fluid they are carrying. From the mod description:

The pipes in the editor view are not active entities, move no fluid, and consume no UPS. They only show the fluid handled by each network for convenience. Instead, fluids are periodically moved directly from input connectors to output connectors on the same network by script.

As a result, the length of the underground pipes is also completely unimportant.

With the default transfer threshold of 2500 and an income of ~390 oil/minute (as shown in the production summary graphs), there will only be enough oil available for Pipelayer to consider it worthwhile to do a transfer every ~6.4 minutes. I don't currently see anything wrong with the mod, it just looks like you don't have enough oil income hooked up.

Your LTN connected oil supply is not working because the request threshold is set to >= 25000, but the tank only holds 24999. When I changed this threshold, a train was immediately dispatched. In the map that you've uploaded the LTN oil unloading station isn't connected to anything anyway.

Note that the fact that the underground pipes are full means nothing.
Ohhh now everything makes sense, i thought i had tons of oil all this time from looking at the pipes.
I was in the proccess of building the LTN oil network, i thought i had a ton of oil stored due to the 10k buffers everywhere.
Thanks for the quick response, really opened my eyes.

Glad I was able to help! Since it's likely other people will also be confused, I'm considering changing the underground pipes and connectors to show themselves as holding 1 fluid, instead of their max capacity. This way you can still tell which pipe is which, but it won't make you think you have multiple 10k buffers waiting to be consumed. :)

However it could be confusing in exactly the opposite way, where a player with plentiful resources available will wonder why all the underground pipes are (almost) empty.

Im not familiar with modding but if were doing it i'd either make it show something other than a number, preferably nothing at all, or just make sure that info about the pipes having nothing in them is more visible somewhere.