@rkrenicki The nipple on the regulator. I only disconnected the hose from the regulator though. I know it needs vacuum, but I'm not exactly sure how the regulator works. Why would it allow fuel to pass out of that nipple and down into the intake port?
There is a diaphragm between the fuel feed and the fuel return. The vacuum from the cylinder will pull on the diaphragm to regulate the amount of fuel that gets returned. The fact that you have fuel coming out of that nipple means that the diaphragm has developed a hole, and now fuel is getting directly into the vacuum line. That at least provides a definitive answer here. As for replacement, I would reach out to G&R Imports first with a photo of the part (they will ask for one, regardless of how good your description is). They more than likely can source one from their junkyard in Missouri. Last time I reached out to them, they had two supercharged Sambars there. If that does not pan out, I can do some digging on the auctions and see if I can find one for you there, but they very rarely pop up on there.
Thanks @rkrenicki I sent Derek at GR an email with a photo earlier this afternoon. I'm a bit surprised no one has thought of a workaround for this issue or found a part that could be modified to make work....even if the return line needed to be routed differently to the main fuel pipe back to the tank. Please keep me posted if you find anything. I can DM you my phone number and email if that's easier.
To be honest, you are the first person who I have encountered with an actual regulator issue on a Sambar. It hasn't exactly been something that required a workaround as of yet. The other people that I know of with issues were all on Vivios, and those have a different setup anyways.
Lucky me! Feels like I'm on the hunt for a needle in a haystack. Hopefully something will turn up at G&R.
@rkrenicki Derek at G&R Imports found a used unit in their parts stash! He says they pull parts from known running engines. I'll update once I receive it and have it installed.
UPDATE: the used fuel pressure regulator solved my issue! Add this to the archive of potential reasons when someone experiences similar symptoms. It is running better than ever now, much peppier. Probably due to the fuel injector cleaning.
