Terminology
Fuel Pump - This is mounted inside the gas tank and sends fuel to the engine.
Fuel Hanger - This is what holds the fuel pump inside the gas tank in the car.
Fuel Pump Controller (FPC). This module controls how hard the fuel pump works by regulating the ground side of the circuit. The ECU tells which setting to use, low, medium, or high. This is important because it keeps fuel pressure low at idle and higher when the engine needs it under load. In addition, it aids in lowering fuel temps because the pump will generate less heat by not working as hard during conditions where it doesn't need to.
Why would you want to hardwire your fuel pump?
Normally, the power for the fuel pump goes through the FPC. When the power loops through the controller there is a step down in voltage on the output side going to the fuel pump. To avoid this and get maximum voltage/power to the fuel pump, we utilize the battery as the power source by running a wire from the battery to the fuel pump via a relay to eliminate this step down issue through the FPC. There are a few ways to do this but iWire has designed a kit that retains the factory safety shutoff and the low, medium, and high settings. This helps your car run better and is safer overall.
What makes iWire's FPC Hardwire Kit different than others?
Don't confuse other products labeled as "kits" since they are typically just a basic relay with inline fuse and the customer is pretty much left on their own after that. To install one, you'll have to hack up your factory harness and try to figure out what goes where. These technically work but your fuel pump is at max power all of the time which can leads to issues like high fuel pressure during idle because the return system can't keep up.
Our product is an actual kit where we have thought out all of the common problems and created a system that is simple to install and doesn't require any cutting of the factory harness. In addition, the iWire kit keeps the ground side for the FPC in place so you get to keep the low, medium, and high setting from factory but you are still getting more voltage to the fuel pump. All of our kits come with step by step instructions that include pictures to make install as easy as possible.
What cars does the iWire FPC Hardwire Kit work on?
Our kit works on any Subaru that has a Fuel Pump Controller, so basically every turbo Subaru. The only Subaru models it does not work on are 2015+ WRX, 2014+ Forester, and BRZ. These models are direct injected with a high pressure pump so a hardwire kit is not needed.
What kind of Fuel Pumps does it work with?
We have three types of kits to cover most of the various setups. If you don't see a kit that will work for you, let us know as custom options are always available. Currently our off the shelf kits work with most combinations of fuel pumps and hangers.
To learn more about our specific kits, please click below.
