How to rewire install fuel pump relay mod. Contributed By Enginebasics. When putting in an aftermarket fuel pump or looking to get more fuel out of your factory pump, one mod worth doing is re wiring that fuel pump. The purpose of this is to make sure that the fuel pump is getting a good, clean voltage that wont fluctuate or change based on other electrical conditions the car is going through. What I am saying is that we want to make sure that our fuel pump is receiving 1. Also, with the average fuel pump replacement cost between 3. The factory wiring of the fuel pump is tied in with many other parts of the cars electrical system. If there are any fluctuations in voltage in this system, the fuel pump will also be affected. Just think about when you have the radio turned up, or running the high beam lights, or maybe when the alternator starts to weaken. When we are running a performance car at the limits, having a fuel pump start to lose voltage, and therefore lose flow, can cause catastrophic problems. Motors running right on the edge of tuning could go slightly lean enough to start detonation in the motor and cause a total failure. The best way to avoid this is to wire the fuel pump to have a dedicated voltage line right off the battery so that it consistently performs. How to start Re wiring your fuel pump The steps of re wiring your fuel pump are to first get to your fuel pumps wiring. At the wiring you need to find the 1. ECU to the fuel pump. Once that wire has been found cut that wire so that you now have half of that wiring running to the fuel pump, and the other half running to the factory ECU. Choosing a Relay The relay you need should be a four prong relay with at least 1. You do not want to get a relay that cannot handle the amperage that your fuel pump might pull causing the relay to fail, and you to be stranded on the side of the road. Wiring in the Fuel Pump Relay The relay should have 4 pins on it. They are usually labeled 3. Steps 1. Wire pin 8. ECU that you just cut. This 1. 2v wire will now energize the relay to turn on. So now instead of the stock ecu energizing the fuel pump, it will energize this relay. Wire pin 8. 6 to a good ground on the car. Be sure it is a good clean ground, and use appropriately sized wire so you dont burn up the relay. In fact you should be using appropriately sized wire for all of this. Run a dedicated wire from your battery to pin 3. Run a wire from pin 8. Electric Fuel Pump Install Diagram' title='Electric Fuel Pump Install Diagram' />Now to explain what you just did. The relay is just like a light switch. Anytime it receives 1. There are a lot of electric motors out there, but just a few make up the majority of electric car motors being used today. Camper trailers tech tips. This video is about how to install a new Airtex fuel pump. How to Install New GM Wire Harness on Fuel Pump. How to test an electric fuel pump. How to rewire a fuel pump off a relay to upgrade fuel pump voltage for max performance and efficiency and pull more current and amperage for better flow. PUMP MOUNTING AND INSTALLATION The best location for mounting any electric fuel pump is the rear of the vehicle. The inlet and outlet of the pump must be. Electric Fuel Pump How to Do It Right. Want an electric fuel pump to last forever and work right Were going to show you how to install it and wire it up the. CHAPTER 4 FUEL SYSTEM. The fuel system for gas turbine and reciprocating engines is the same. It delivers to the engine fuel metering system a uniform flow of clean. I need a wiring diagram for an electric fuel pump, with a relay and oil pressure switch. M47500A. 2 Owners Manual Electric Stationary Air Compressor 230V, single phase60 gallon, 3 HP and 5 HP Instructions for InstallationSetup, Operation. Being that pin 8. Once the car is shut off, pin 8. Ingenious right If this is too much for you, this modification has become so important that companies sell ready to wire kits If you have any more questions on how to do this particular modification to your cars factory wiring harness, click the contact us button and send us an email. FuelPumpWiringDiagram.jpg' alt='Electric Fuel Pump Install Diagram' title='Electric Fuel Pump Install Diagram' />Questions we have recieved From Reader Barry how to re wire a fuel pump off a relay. It doesnt matter which one you take to ground as long as the other you have as your triggered 1. Example   If you take 8. If you take 8. 6 to ground than make 8. Make sense Enginebasics. TeamTo Enginebasics. Electric Fuel Pump Install Diagram' title='Electric Fuel Pump Install Diagram' />Was reading your fuel pump rewire, and was wondering what you do if you are running two fuel pumps. I have an in tank fuel pump, and a inline fuel pump. Any help would be great. Thanks. Dear Reader,IF you ran large enough wire and a relay to handle the current amps of both pumps than you would run the 1. Only perform this if you calculated the gauge of wire run to match the amp draw of both pumps though and the relay size as well. Good luck, Enginebasics Team PS. Microsoft Office 2007 Blue Edition - Working Tested. Be sure to like us on facebook and share our page with your friends. If you enjoyed the information and article you just read be sure to check out our newly released book with even more exciting photos and information.