Randeez 2012 Budget Yukon Denali Build (stick on hood scoops galore)

randeez said:

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kbuskill said:

I always wondered how they did dual pumps in the tank. Never enough to research it, but was kinda curious nonetheless.

Is there any kind of check valves that keep the pumps from fighting each other or???

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randeez said:

for this set up: they can put a small screen on the pump, but not an actual filter sock - so i had to add an external fuel filter - not that big of a deal.
there usually isnt any kinda of check valve, most of the intank pumps have some sort of a checkvalve to not allow flow back threw them. most people will have just one pump on and some sort of trigger to turn the second pump on (psi switch or something like that)

the way i am controlling them, the first pump is controlled by the factory fpcm and im using a vaporworx controller that taps the power wire to the first pump and then mimics the PWM signal. set up like this the fpcm doesnt know there is a second pump but it thinks the first pump is much larger/more efficient. so what used to take (making up round numbers) 40% duty cycle with one pump to maintain 60psi now only takes 20% the fpcm doesnt really know or care why it only needs half the duty cycle its just reading pressure and hitting target psi. so both pumps are always on.

SOOO onto my problem. this aftermarket dual pump module- had a little plastic manifold/4way that connected: outlet-pump-pump-pressure relief. the hose/tube down to the pressure relief was just blowing out fuel the whole time. so my pumps were running ridiculous duty cycle just to maintain idle psi and as soon as fuel was needed it acted like they were tapped out. so i just gutted the whole thing, changed it over to a standard tee for pump-pump-outlet which i increased to 1/2" new bulkhead, deleted the relief valve

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