Forums/Z31P/z31-performance-upgrade-forums engine-management/Anatomy Of: Failed FPR

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Z_Karma: (2019-05-02 01:28:11)

My Black Z had the telltale smell of fuel at the vacuum port of the FPR. I removed it and replaced it with another one of unknown vintage, but after a autopsy I sprung for new OEM ones for both running cars. (I'm using a walbro 255LPH and stock injectors in both.) I was curious as to what a failed diaphragm looked like on the inside irl, instead of just the FSM drawing.

fpr1.jpg

fpr2.jpg

fpr3.jpg

I had bench tested the diaphragm by using a hand vacuum pump and pulling ~22inHg of vacuum and letting it sit for a couple hours and saw no obvious leak at room temperature.

But the diaphragm was porous enough to let fuel, or at least fuel vapor through it and probably once warmed up to underhood temperatures, became more porous.