I have a honda civic where I have enlarged the fuel filter exit areas through the bolts power is better but high sound coming from the fuel pump I never here before.
My car has a manual transmission.
Anytime there are modifications on a vehicle from the standard component or part can cause unknown problems. When you modified the orifices in the fuel filter banjo bolts you may cause excessive volume of fuel to go through the fuel system and cause the fuel pump to become noisey. The manufacturer had specific sizes to limit the flow of fuel into and out of the fuel filter. If you think there is a problem with the fuel pump that is not related to the changes you did then call a mechanic like one from YourMechanic to come to you and diagnose the noise for you.
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