How to Hot Wire Your Fuel Pump With a Relay in the Trunk
Terry Littleton -
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 protector.
  1. 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.

  2. 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 Bosch
    and it seems a lot sturdier. Good choice.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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 alternator.

  8. 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.

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