RotaryBuddha

iTrader: (4)

So I figured I would make a nice contribution to this forum. Many people don't know about the fuel pump rewire in our cars. And I haven't seen anyone make a drawing like this yet. So here is a wiring diagram on how to do it. In this example the relay is mounted in hatch where the tool kit would normally be. This applies to any aftermarket or stock fuel pump. If you can't view the attached pdf. Here is a .jpg

http://i21.photobucket.com/albums/b2...lPumpRelay.jpg

dhays

iTrader: (1)

Nice diagram and something that I'd like to do. The only thing that is holding me back is the thought of trying to get another wire from the battery back to the fuel pump. I don't suppose you have photos of how your routed your positive wire from the battery on back?

RotaryPowah!

Thanks in English and everything. Took me forever to learn how to read the electrical manual.

RotaryBuddha

iTrader: (4)

Ok had a couple PM's asking what type of relay I used. Here is one off ebay. Comes with a nice little harness and everything.

http://cgi.ebay.com/ebaymotors/Tyco-...spagenameZWDVW

FD3S2005

iTrader: (11)

i really wish there were acually step by step instructions on how to install and do this.. i would reallly love to do it

TpCpLaYa

iTrader: (10)

so whats the purpose again? I assume there is less voltage drop so that more power is available at the pump? There was a thread not so long ago that was a fuel pump re-wire mod although you didn't need a new relay and there was minor wire splicing......

I did it, but cant remember the thread....i think dale clark was involved

TpCpLaYa

iTrader: (10)

here we go
https://www.rx7club.com/showthread.p...el+pump+rewire

no need to run a new wire all the way to the pump as well

KaiFD3S

iTrader: (37)

I take it this will work for dual pumps too right...

RotaryBuddha

iTrader: (4)

The purpose of the new wire run is to provided more amperage and voltage. The stock wiring can not handle the full amp draw of high volume after market pumps.

badddrx7

iTrader: (7)

It will work with one, two, three, 5, or 10 fuel pumps....however many you can cram down into the top of your fuel tank....Just increase the wire gauge, fuse and relay size accordingly as you keep installing pumps.

Later

Julian

iTrader: (14)

This method bypasses the step down resistor, thus not slowing to pump down for idle conditions. May not be good.

The other methods of retaining the switching relays but taking power more directly of the battery improve (reduce) voltage drop. If you are still concerned about wire size, then parallel another wire from the relay block back to the fuel pump and increase the gnd. wire size or parallel this too.

You can lower resistance in wiring by either increasing wire size or paralleling wires. (the cross section increases either way) and since the resistance is a combination of all circuit bottlenecks and wire size per length. Taking out some bottlenecks (ignition switch) but leaving a few bottlenecks (relay circuit) but increasing wire size still improves the circuit.

live4boost

iTrader: (2)

Autozone has some nice Pilot relays that work well. Thats what I used. Like mentioned before, this is prob only a good idea for modified cars with aftermarket fuel pumps. You'll want to have something to tune with in order to lean out idle and cruise.

FD3S2005

iTrader: (11)

to bad clubrx has been down for awhile

Dudemaaanownsanrx7

iTrader: (23)

Here is one i drew a little while back, basically the same thing. I put my relay in right under the fuel pump lid @ the hatch area and sealed it with elect tape to keep moisture and dirt away from the terminals. It adds about 2v to the pump and makes a big difference in the afr''s, so i recommend not doing this with the stock ecu and only if you're prepared to tune out the extra fuel.

FD3S2005

iTrader: (11)

dudemaa see that helps a little but i need step after step insturctions with pics to help me out. i really dont want to fk anything up in my car thinking i know how to do it.

Julian

iTrader: (14)

If that doesn't help. Then maybe you shouldn't tackle the project.

Julian

iTrader: (14)

Goals are to make
(1) power sources more direct using battery "B+" power rather than IG1 power; and
(2) to improve current capacity of wiring to pump; and
(3) to improve ground.
This thread has previously presented options for a power source by either going direct from battery or tapping into fuel circuit to bypass the IG1 source and tap into a B+ source. I expand on these options:
(1)
Aa) from battery post to fuel pump by way of new fuse and relay pump (covers 1 and 3 but not clean, messy wiring and eliminates starting, idle low speed pump control)
Ab) tap onto screws under "Main Fuse Block" black w/ white striped wires existing 120a to fuel pump by way of new fuse and relay pump (same as above, a little cleaner install)
Ac) from fourth fuse position (open slot) in "Relay & Fuse Block" to fuel pump by way of new fuse and relay pump (this is cleaner, used OEM fuse blocks and offers low resistance from battery to here and on to pump)
Bc) as Ac) above but tap into Blue "L" Fuel pump wire (as described a few times above), this maintains two speed control of pump (cleanest, lowers resistance by eliminating run to ign switch and fuse block inside car; but does still have resistance of wiring runs and relays)
Bd, option to Bc) improves wiring run by adding a parallel run from junction X-10 under dash on drivers outside footwall to X-24 near fuel pump. Idea is to double up the "W/R" white w/ red stripe wire, as this is the single longest run doubling the wires will drop the resistance and thus reduce voltage drop. Also this is not a hard wire to install going from foot well to rear deck under drivers door sill. This provides B versions about the same resistance reductions as A while retaining speed control (best of all worlds)
(2) see Bd above
(3) I advise running a ground wire from black wire terminal of X-24 direct to nearest chassis bolt and cutting original gnd so as to prevent creating a ground loop.