Fuel pressure and restriction test

[Lonestar10]

that isnt showing restriction the gear pump is sucking the fuel from the fuel tanks to itself there is going to be negative pressure on that port as its pulling the fuel through the fuel filter. if you wanted to see restriction you would have a gauge at that top port and then another gauge before the fuel filters between filters and tank that would tell you your true fuel restriction upto the pump by measure the true resistance of the fuel filters.

lets just say with 3/4inch fuel lines going from tanks to gear pump and for this lets say there are no fuel filters. lets say there is 3 gallons of fuel from the pump suction to the suction in the fuel tank the gear pump is going to create close to the weight of the fuel in suction vacuum to get that fuel from the tank to the pump add in filters and now you would probably add another 10-15% additional vacuum with clean filters.