So my car started to run lean at a certain point. Like 12.3 or 12.4 under boost, and then even up to 13.5 with ethanol. I mounted a walbro 450 earlier this year. Fuel pressure dropped to 38 psi on idle.
I took the pump out on the advice of Seb and checked the fuel terminals. They looked bad, cables brown around the terminals. This seems to happen more as of the 450lph pumps have a higher demand.
For now I have drilled two 9mm holes in the tank hat and made two new connector terminals. Fuel pressure went up by 10+ psi on idle!
So learning: when going 450lph: use the CJM hat (it has an upgraded 40a rated connector) or adjust your fuel hat.
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