Fuel Pump Relay

[Tommyk]

I need to upgrade the wiring to my fuel pump so I can run the standard gtr pump @ close to 14v

Does anyone have any detailed pictures of how to do it?

I understand i need to put in new wiring + relay and fuse and have this connected direct to the fuel pump

Does this mean i need to physically remove the fuel pump and connect the new wiring direct to the pump itself, and put a hole through the grommet and all the other stuff ? Do i need to cut one of the wires leading into the nissan typical 5 plug and connect it to the relay

I would really appreciate any help, because i need to get this done by tuesday

Cheers

[Guest two.06l]

I need to upgrade the wiring to my fuel pump so I can run the standard gtr pump @ close to 14v

Does anyone have any detailed pictures of how to do it?

I understand i need to put in new wiring + relay and fuse and have this connected direct to the fuel pump

Does this mean i need to physically remove the fuel pump and connect the new wiring direct to the pump itself, and put a hole through the grommet and all the other stuff ? Do i need to cut one of the wires leading into the nissan typical 5  plug and connect it to the relay

I would really appreciate any help, because i need to get this done by tuesday

Cheers

<{POST_SNAPBACK}>

Tommyk....ring me and ill step you through it mate....02 49847847

Paul

DIRTgarage

[Mik]

Measure the voltage at the fuel pump before you bother.

The OEM fuel pump relay is in the boot near the battery. There is less than 1m cable between the fuel pump and the battery.

The voltage drop over that length should be negligible...I'll explain why.

Assume the OEM cable has a cross sectional area of 1mm squared (it's actually much thicker)

Assume 1m cable

Assume resistivity of copper is 0.0000000168nΩm at room temp

Now, resistance of the 1m cable = resistivity x length / area

= 0.0000000168nΩm x 1m / (1/1000000)m

= 0.0168Ω

Now, voltage drop is given by current x resistance

Assume the fuel pump draws 10A (should be a bit less)

Voltage drop = 10 x 0.0168 = 0.168V

Which is next to nothing

Soemone please correct me if I'm made any errors

[Cubes]

Thats correct Mik, however the high low resistor is what causes the fuel pump not to receive the full volts when under load.

Unsure why that is my understanding.

Running a dedicated power feed does indeed help.

I'll be grabbing the multimeter and checking mine out. I run an external and internal pump, both of those running flat stick must be drawing quite a few amps, hence my reason to upgrade the wiring to a minimum of 30amp stuff.

[BHDave]

I have run dedicated 30 amp wiring with a 20 amp fuse for my external pump (044). A relay is triggered off the factory power feed to the intank pump. The intank pump (walbro) is still running off the factory wiring through the stock 10amp fuse with no problems.

I also run a surge tank with the return line feeding back into the top so the 044 is effectively feeding itself once primed if the walbro cant keep up.

Only problem i have is the PFC doesn't prime the pump long enough for the 044 to build up rail pressure so i have to turn the car to reds, then off, then back on before cranking.

[Cubes]

Do you use the existing negative (earth) or do you create another to the chassis?

[PHATR32]

best to use a fatter earth going directly to a clean section of the chassis.

steve