BMW sources a couple different vendors so this is just one possibility. Put your fuel gauge on and start the car. If the needle vibrates around an average of 50 vs. dead stable sign of o-ring leaking.

Then let it sit overnight. I forgot the numbers I had but before was zero psi overnight after was 20-30 psi overnight. If psi drops below say 10 overnight the o-ring is leaking between your FPR and fuel filter. Unlikely three FPR broken or the filter is plugged enough to be a problem.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)