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Feeding a gravity fed fuel pump

28K views 9 replies 7 participants last post by  Pupsvette76 
#1 ·
This posting is one of shear curiosity ... I was working on a friends car that he just bought and i was looking at the fuel system that the car came with it had a Holley blue pump which as far as I know is a pusher(gravity fed) pump and when I looked at the fuel cell I saw that there were no fittings on the bottom only fittings on the top do i looked inside and saw a large large hose from one of the fittings to the bottomw of the tank. How could the outlets be on the top ... How do you gravity feed a pump when the fuel has to come up a hose to the top of the cell and down to the pump to be pushed to the carb
 
#2 ·
I dont think those pumps have the ability to pull fuel out or up if mounted above the tank.

The pump needs to be mounted below the opening of the inlet tube that is inside that gas tank, it is shipon feed to the inlet of the pump at first.

Once the flow is established the pump will to some degree create some of its own low pressure on the inlet side to aid in the coninual flow of gas out of the tank.

Thats my take on it
 
#4 ·
i was stumped cuz it runs great and i couldnt figure how fuel is being delivered when the fuel pump isnt being fed any fuel ... like when you shut the engine down and the fuel runs back down the hose in the tank out of the fuel pump when you go to start it again how does fuel flow up and out against gravity
 
#8 ·
Here's my take on it.
The pick up tube in the tank is located near the bottom of the tank so it is under gasoline all the time. The fuel delivery system is sealed. When the pump turns on it is going to start pushing whatever is in the line. That could be air in a new system or one that has been sitting a bit.
A vacuum is created in the line to the tant and gas begins to flow to the pump because of the sucking action.
Once the gas reaches the pump it is pushed ,just like the air that was before it.
It is better to have the pump located below the top of the tank and as close to the tank as possible as they push better then pull.:confused:
 
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