This is also known to many DSM enthusiasts as the "hard wire mod".
RRE has plenty of info on why you should rewire your fuel pump.
Not like I really understand all that flow vs psi vs voltage stuff, just thought
it would be a good idea to do it and get more flow since I already had the
battery in the trunk. I got my relay, inline fuse holder, and other stuff from
Radio Shack. Pretty simple mod, just splice the relay into the car side of the
harness (crooked yellow arrow in pic):
Here's a summary of how I did mine: First, I cut the black wire with
white stripe on the car side of the harness, and now I have 2 halves of the wire:
one going to the car, and one going to the pump. I ran some 10 ga wire (red) from
terminal 87 of the relay (power out) and connected it to the black/white stripe
wire that goes towards the fuel pump. This is the new power source for the fuel pump.
Next, I ran a fused 10 ga wire (red) from the positive terminal of the battery
into terminal 30 on the relay (power in for the relay). Then I took the other half
of the black/white stripe wire (car side) and connected it to terminal 85 on the relay,
and ran a 12 ga wire (black) from terminal 86 on the relay (this is the ground for
Another view of the relay and wires (you can't see 85 in this pic):
If you look behind the plastic panel, there's already a screw with a
wire ground on it so I just ground 86 to that same screw. Here's a pic of
everything connected and secured with zip ties: