Hardwiring Fuel Pump

SON240sx Automotive
1

So last drift day, I had a short in my wiring somewhere and kept blowing fuel pump fuses. After some help from the drift posse crew (Peter and Francisco), I managed to directly wire the pump to the battery so I could keep on drifting.

Now, I want to do it properly. So I’ve done some research and have one small problem.

So you run power directly from battery, to fuse, to relay, then to pump. And run the fuel pump switch using the grounds, with a ground being directly to the body near the fuel pump.

My question is how do I wire the actual relay into the system. I opened up both the EGI pump and EGI relay (also don’t know which of the two is for the fuel pump), and there is 4 wires to each. EGI has 3 reds 1 black, and EGIi pump has 4 blacks with stripe on each. Which of the two relays do I use? Which of the 4 wires do I wire up for the relay to work correctly with my system?

Thanks

2

Are you trying to tie the fuel pump operation back into the ecu like oem?

Or only off of a switch

3

no, a relay is a kind of switch

it literally relays, or joins, two circuits together

it lets you control high amperage circuits (ie fuel pump) with a low amperage switch

you will still need a switch to “turn on” the relay, though

in the oem setup it is the ecu that “turns on” the oem fuel pump relay, thereby controlling the fuel pump operation (for example, the 5-second priming sequence)

if you wanted to forget about the ecu and just want the fuel pump controlled by its own on/off switch, it’s very easy to wire (but yes you will still need a relay)

4

Ok, so wire in a relay without ecu, which wires on the relay should I be wiring into the system.

---------- Post added at 07:36 PM ---------- Previous post was at 06:59 PM ----------

From all the reading im doing.

I don’t need the relay at all then.

Relay is there to do the 5 second prime via ecu, and turn pump off 1 second after car is turned off. Its litterally a switch like Mike said.

So, since I’m hardwiring it to my own switch so i have manual control over it (like in race cars), I don’t need the relay at all.

I can connect power, to fuse, to pump. Run a switch on the ground side to complete circuit.

No need for relay… right?

5

nvm figured it out.

6

haha ummm

what did you do?

b/c everything you wrote in the post above is wrong :stuck_out_tongue:

---------- Post added at 09:34 AM ---------- Previous post was at 09:09 AM ----------

i suck at drawing but here’s a quick one of what it would look like

keep in mind this is completely independent operation of the ecu

turn switch on, fuel pump stays on

off, off

thassit

it doesnt matter where the relay is actually located, either. as long as the wiring follows the drawing

http://spd.blinkerfluid.org/images/fp.jpg

---------- Post added at 09:39 AM ---------- Previous post was at 09:34 AM ----------

PS that’s using a standard bosch 4-pin relay, not a nissan relay

basically what happens is this:

the green circuit is the relay’s “control” circuit

you control +12v to the green circuit with your on/off switch

when you flip the switch, the relay gets +12v across pins 85 and 86 (green circuit), and it makes the connection between pins 30 and 87 (blue circuit)

do not wire your fuel pump directly to the switch

7

That’s what I did cept I used the ecu signal wire directly from ecu to control relay instead of battery. And then I put the switch somewhere for theft purposes

8

That sounds like an acceptable solution.

So you should have a heavy gauge power wire running to the relay, from the relay to your pump, and you should have a smaller circuit (the oem fuel pump circuit) controlling the relay, with an additional switch wired in for anti-theft. You shouldn’t have any problems with that. It’s a common solution for those running Walbros or other higher output pumps than stock. As long as everything is wired like Mike drew out (nice drawing btw buddy), you should be good to go.