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Guest Message by DevFuse

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fuel pump wiring questions

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2 replies to this topic

#1 Uberoo


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Posted 15 July 2012 - 03:51 AM

I'm not sure where I should put this so mods feel free to move it where-ever you feel is most appropriate.

I'm planning on adding a surge tank to my 81 hatchback with a ej22 and I got a question on wiring it. Currently my fuel pump is ran by the computer.I was just wondering if it would be possible to send power to the low pressure pump for a second or so to fill the surge tank than turn on both pumps then start the car.What I am thinking of is something that gets voltage when the fuel pump wire from the computer is hot sends power to the low pressure pump for a second then sends power to both fuel pumps.Is that something easily done or should I run the low pressure pump by a momentary switch and the fuel pump wire from the computer?Press the button then crank it over.It would be really great if it happened automatically but I suppose I could remember to push a button then start the car if it would be too much work.

thanks in advance

Edited by Uberoo, 15 July 2012 - 03:56 AM.

#2 GeneralDisorder


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Posted 15 July 2012 - 02:26 PM

Surge tank should always be full so you shouldn't have to do anything but run both pumps - add a second relay and run it from the same signal as the existing fuel pump relay. The only time you would ever have to worry about it is when you need to pre-fill the surge tank - like the first time you start it or if the system has been purged of fuel. For that I would add a momentary switch under the dash somewhere to cycle the delivery pump as long as it's held down. All that switch would do is ground the delivery pump relay when you have the key on but are not cranking it.


#3 Uberoo


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Posted 15 July 2012 - 08:02 PM

so wire them both to the computer controlled fuel pump relay,but the first time unplug the high pressure pump until fuel flows from the surge tank into the main tank from the return. I can do that.

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