Hot Wire Your Fuel Pump With a Relay in the TrunkTerry Littleton - firstname.lastname@example.org You Will Need
Get 15 ft 10 gauge wire, 3 ft 14 gauge wire, and a Bosch 4 or 5
prong 30 amp relay. Any place that installs car alarms should have a Bosch
relay. Get a heavy 10/12 gauge wire 30 amp fuse holder. They can be found at
auto parts stores and come in the old glass or new plastic spade type fuses.
Make sure it is heavy wire and not like most that use like 14/16 gauge wire. You
will need 2-10 gauge butt connectors, 1-10 to 16 gauge butt connector, 2-10
gauge female spade connectors, 2-14 gauge female spade connectors, 1-10 gauge
and 1-14 gauge ring connector. Soldering gun, wire
- Disconnect battery. Put a ring connector on one end of the 10
gauge fuse wire and attach that to the post at the rear of the alternator. Run
it over to the front of the drivers side valve cover and attach to a piece of
ten gauge wire that you will run to the back of the car. I put mine inside the
car and it was actually easier.
- Run it through the hole next to the powermaster where all the
wires go through the firewall. I routed it over behind the emer brake pedal,
down behind that kick panel, took off the sill plate and put it inside the
plastic wire protector (it does come open, just a pain to figure it out). Take
out back seat and run it from sill up to opening that goes into the trunk. There
are other wires that do the same thing, just follow them. Bring wire down to the
hinge support. There is already a hole right there to put a bolt and nut through
to mount the relay. I had a radioshack relay but it broke so I got a
and it seems a lot sturdier. Good choice.
- Just a word of caution. Follow the wires down to the side of the
trunk floor. The copper colored wire is the one to attach the trigger wire to.
It looks like bare copper wire but is actually coated. The coating is so hard, a
regular scotch lock wouldn\'t make contack on mine, so I cut out a half inch
section of the insulation and soldered the trigger wire (a small piece of 14
gauge from the relay prong 86) to there. I wrapped it in tape and put corrugated
wire guard over it.
- The ground wire from the relay (a small piece of 14 gauge from
prong 85) can go to the bolt hole you use to mount it to the hinge support. Just
clean off the paint first. Then hook up the 10 gauge wire from the alternator to
post 30 on the relay. The remaining prong on a 4 prong relay is the "Power Out"
that will feed the alternator voltage to the pump(s). If you have a 5 prong
relay the two remaining prongs should be labeled 87 and 87a. One is the "Power
Out" when relay is energized, the other supplies power when the relay is not
energized. Use a test light to determine.
- Run the remaining heavy gauge wire from the "Power Out" prong
(when energized) from the relay through the rear of the trunk to the fuel pump.
Notice the plastic cover over the BIG rubber grommet that takes all those other
wires from the trunk out under the back of the car? Forget about getting your
new ten gauge wire through there. Just drill a hole big enough to run the wire
through covered with some corrugated protector. I put mine right next to the
rubber plug. Then run the ten gauge wire to the pump.
- The 3 wires going to the sender/pump are Black-Ground,
Pink-Fuel Level Sender, and Brown/White Stripe-Fuel Pump motor. Cut the
Brown/White stripe wire after the connector on the fuel pump side and attach the
new ten gauge wire. Leave enough to reconnect stock later if desired. Put a butt
connector on the old cut wire so it doesn\'t short on anything. I wire tied stuff
up neat and used wire protector. If you have an external pump, you can run
another piece of 10 gauge to it for power from where it splices into the
original pump wire.
- Now the wire coming through the firewall goes over behind the
drivers valve cover and along the back edge of it under the EGR tubing in wire
protector and splices into the other fuse wire from the
- When you turn on the ignition, you should hear the fuel pump
prime. The only problem I had was in the connection of the trigger wire to that
copper colored wire in the trunk like I mentioned above.
Hope this isn\'t confusing. I did it this way to keep things neat
in the engine compartment.