Ok I've pretty much determined that most of my fueling issues are related to fuel pressure. I'm trying to determin how the heck the stock 02 fpr works so that I can decide which areomtive unit to use and how to bypass the stock unit.

What I know:
There's a round thingy on the feed line, is it some sort of damper?
There's something that looks like an fpr in the drivers side end of the rail, stock it connected between the air filter an throttle body. If that is the fpr that would mean that it read atmospheric at idle and vac based on the velocity of the intake air. And it would have increased pressure based on vac. I have it to manifold pressure at the moment and from what I can tell it doesn't effect afr whether its connected or not.
If it is the fpr that means there's a tube inside the fuel rail that goes to the return line on the passenger side of the rail.
If that's not the fpr, who the heck is fuel pressure controlled on the 02's? There's no restriction in the return line.


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Hook up a gauge to the schrader valve and test. I think it is a FPR.



FU Tuning