Car struggles to make fuel pressure

phunk

The keyway you describe is where fuel bleeds from the filter housing to the inlet of the regulator.

The regulator delete fitting crushes the smaller lower oring when its seated and tightened down. But it is not supposed to crush the larger top oring vertically. That oring seals by the pressure applied to its sidewalls between the housing and the delete fitting, which is also how it sealed to the factory regulator.

I am surprised it was your upper oring that was leaking. An upper oring leak would allow pressure to leak externally. A lower oring leak would allow pressure to leak into the return channels.

So to clarify, you replaced the factory o-ring and the problem was solved, and kept the same o-ring that we supplied?

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