FPC Hardwire Kit Install Guide - Stock Hanger Older Vehicles

Table of Contents

1 Compatible Vehicles
2 Welcome!
3 Warning
4 What’s included
5 Stud Bypass Kit Components - AEM 340; Walbro 255; DW 200; DW 300;
6 Stud Bypass Kit Components - Walbro 450; Walbro 525
7 Battery Relocation Kit Compatibility
8 Section 1: Installation Overview
9 What it does
10 Tools needed:
11 Section 2: Battery/Engine Bay Connections
12 Section 3: Secure the Circuit Breaker (CB) to the Battery Post
13 Section 4: Running the Large Red Power Wire to the Rear of the Car
14 Section 5: Accessing the Fuel Pump Controller
15 Section 6: Installing Fuel Pump Bypass Module
16 Section 7: Accessing the Fuel Tank
17 Step 8: Stud Bypass Kit Installation
18 Drill holes into the hanger for the stud kit
19 Install the Stud Kit Through the Hanger
20 Hooking Up Wiring to Stud Kit
21 Section 9: Getting “Key On” Power to the Red Wire to Turn on the Relay.
22 Section 10: Reconnecting Battery/Power
23 Step 11: Testing and Final Clean-Up
24 Troubleshooting

Compatible Vehicles

2002-2007 Subaru WRX
2004-2007 Subaru STi
2004-2008 Forester Turbo
2004-2006 Baja Turbo
Pre-2002 with 2002+ Turbo Engine Swap (Requires Merge + FPC Extension Harness)

These vehicles will will come with metal fuel hangers

Welcome!

Thank you for purchasing the iWire Plug and Play Fuel Pump Hardwire Kit! These instructions are designed to make the installation process as easy as possible. Please read and follow them carefully.

We suggest reading the entire guide before beginning the installation of this product.

Warning

This kit is designed to modify your Subaru's electrical and fuel systems. Working around electricity and fuel vapors can be dangerous and even deadly if proper care is not taken. While iWire takes pride in making our products as simple as possible to use, we still recommend that a professional, qualified technician perform the installation. Any modification to a vehicle that exceeds the original manufacturer specifications (which includes OEM fuel tank connections) carries an inherent risk of mechanical failure that could result in damage to life or property. iWire is not responsible for any damages that may occur. By purchasing this product, you agree to these terms of sale.

What’s included

Battery to Circuit Breaker Sub Harness
Circuit breaker
Battery Cable to Hardwire Module
Hardwire Module
Hardware Kit
Ground Terminal
Fuel Pump Controller Jumper Harness
White connector with Orange wire for Secondary Pump Expansion (stays open for single pump kits)
Ground and Power Wires for the Fuel Pump
Red Trigger Wire (add-a-fuse in hardware kit)

10. Ground and Power Wires for Fuel Pump (length and terminals may change based on car model and year)

11. Stud Bypass Kit

Stud Bypass Kit Components - AEM 340; Walbro 255; DW 200; DW 300;

(1) Fuel Tank Harness Jumper
(2) Plastic Acorn Caps
(2) Black Insulators
(2) Metal Studs
(1) Shrink Tube
(1) Butt Connector
(4) Black Plastic Washers
(4) Metal Nuts

AEM Type Stud Bypass Kit Components

Stud Bypass Kit Components - Walbro 450; Walbro 525

(1) Fuel Tank Harness Jumper
(1) Walbro Connector (Black)
(1) Walbro TPA (Blue)
(2) Plastic Acorn Caps
(2) Black Insulators
(2) Metal Studs
(1) Shrink Tube
(1) Butt Connector
(4) Black Plastic Washers
(4) Metal Nuts

Walbro Type Stud Bypass Kit Components

Battery Relocation Kit Compatibility

If you have also purchased the Battery Relocation Kit and the iWire Hardwire Kit to iWire Battery Relocation Adapter Cable then you will not use the following parts.

Battery to Circuit Breaker Sub Harness
Circuit breaker
Battery Cable to Hardwire Module

Instead, the Battery Relocation Kit main cabling will be utilized, and the Adapter Cable will connect to the CB aux side of the circuit breaker and then directly to the main post on the fuse/relay block on the hardwire kit (part #4).

Section 1: Installation Overview

Large Red: Power wire from battery positive terminal

Dotted Red: 12V Key on power source (connect to fusebox with add-a-fuse)

White: Power output wire from iWire fuel pump bypass module to fuel pump plug

Blue: Ground wire from FPC to fuel pump plug

What it does

The iWire Fuel Pump Hardwire Kit modifies the original control system to allow the pump to run at maximum flow for high-output applications requiring additional fuel. The kit works by increasing the voltage to the power side of the pump while still leaving the ground side in place, thus keeping the OEM low (33%), medium (66%), and high (99%) settings. iWire upgrades the grounding side of the controller to maximize the FPC's grounding capabilities to ensure the best possible performance.

Tools needed:

10mm socket or box wrench
12mm socket or box wrench
13mm socket or box wrench
Flathead screwdriver
Box cutter or knife
Jack stand

Section 2: Battery/Engine Bay Connections

Before installing the iWire Fuel Pump Controller Kit, disconnect the negative terminal from your vehicle’s battery. This is a very important step to ensure your safety while installing the kit.

Remove the washer fluid tank by first unscrewing two 10mm bolts at the top of the tank. Then, disconnect the green electrical connector and the washer fluid line from the bottom of the tank and remove it from the engine bay.

Locate the hole in the vehicle’s firewall just behind the brake and clutch pedals. Cut a ¼ inch slit in the rubber grommet that plugs this hole and feed the power wire through the slit. One end of the Red power wire is covered in a protective black Raychem DR25 sleeve which the writing on the sleeve can identify. This is the end that should be run through the firewall and into the engine bay.

The wire should now be visible from inside the engine bay. Look for it just below the brake booster. Carefully reach underneath the brake booster and feel for the ring terminal that is pushed through the firewall grommet.

Pull the Red power wire through the firewall carefully, making sure to keep the rubber grommet in its proper place until there is enough length to reach the positive terminal on the battery.

DO NOT CONNECT THE WIRE TO THE BATTERY YET.

Section 3: Secure the Circuit Breaker (CB) to the Battery Post

Thread the nylon lock nut onto the battery tie-down bolt until it matches the height of the battery tie-down.

Then slide CB on top.

Screw on the lock nut until tight with the circuit breaker. Do not over-tighten this.

Attach the long battery wire going to the module in the back to the Silver colored side of the post.

Attach the short wire that will go to the positive side of the terminal to the Copper colored post.

DO NOT CONNECT THE WIRE TO THE BATTERY YET.

Push the Red boot down to cover exposed terminals.

Section 4: Running the Large Red Power Wire to the Rear of the Car

Remove trim from the driver’s front door sill. First, unscrew the plastic retaining clip located next to the dead pedal.

Use a flathead screwdriver to pry out the body clip holding the trim to the front of the door sill.

Then, simply pull up on the trim, and it will unclip.

This will expose the edge of the carpet and provide a way to run the Red power wire to the rear of the car.

Move to the back of the car and remove the rear lower seat cushion. Two 12mm bolts, one below each rear seat, hold it in place.

Remove the rear door sill trim and B-pillar trim (below the driver’s seat belt) from the driver’s side.

One plastic plug holds the door sill trim, and the other holds the B-pillar trim.

Run the red power wire along the driver’s side door sill to reach the rear of the car. Run the wire along the gap exposed between the carpet and the metal edge of the door sill. Ensure the wire isn’t stuck on sharp edges and won’t get pinched when the trim is reinstalled.

The Red power wire needs to run along the reinforcement bar under the rear seat. Loosely secure the wire to the bar with cable ties and ensure the wire is tucked safely out of the way. Don’t pull the cable ties tight yet. The ability to adjust the wire until the very end of the installation helps ensure a proper fit.

Section 5: Accessing the Fuel Pump Controller

Remove the rear seatback by unscrewing the 12mm bolts at the bottom of the seatback.

Remove the passenger-side rear seat back support bracket and the attached trim. Unscrew 12mm bolts and use a flathead screwdriver to remove body clips.

Remove the bottom carpet in the trunk area. Just pull up on it gently and lift.

Unscrew the plastic nut that holds the trunk liner to the plastic trim near the trunk latch.

The side trim is secured by body clips that can be removed with a flathead screwdriver.

Section 6: Installing Fuel Pump Bypass Module

Plug the FPC jumper harness in between the FPC and the original FPC connector. The original FPC is inside the passenger rear quarter panel. Please note that the white plug with orange wire will stay loose if you install a single pump. Just leave this plug zip-tied as is. It is designed for future upgrades to a double pump kit.

Above is the final layout of plugs as they attach to the module. While this is shown outside the car to make it easier to understand, it will be done inside the car.

The picture below shows the completed mounting and routing.

Ground the ring terminal to the chassis. An empty bolt spot would work like this. Just make sure to sand the paint away to ensure the best grounding possible!

Install the FPC pump bypass module on the passenger side of the trunk using the supplied hardware. Use the short bolt, the large washer, a lock washer, and a nut to secure the bracket to the sheet metal inside the trunk. A hole should already be available to put the bolt through, but one can be drilled if needed. The bracket will space the module away from the car's body, allowing for easier installation and connection of wires. Secure the module to the bracket with the long bolt, a lock washer, and a nut. The bolt heads and nuts are 10mm.

Run the Red power wire through the provided Red rubber boot and attach the ring terminal to the stud on the module. Secure the ring terminal with the included 13mm nut.

Section 7: Accessing the Fuel Tank

Run the White and Blue wires from the module to the back seat.

Remove the 4 Phillips head screws that secure the fuel pump access door.

Locate the rubber grommet underneath the passenger-side rear seat. It will be somewhat tucked away underneath the support bar, but wires are running through it. Pop this grommet out and use a blade to cut a ½” slit in the rubber for wires to pass through.

Feed the white power wire and the blue ground wire through the newly cut grommet until they are visible underneath the car. (The Wires may look slightly different if you have our Bypass Stud Kit, but you will still complete the following steps to get the wiring to the fuel pump access door.)

The next step is tricky and may take a few tries to complete properly. Be patient.

We took another wire with a ring terminal attached to it. We dropped this down from the opening above the fuel hanger.

Then, we bent the stock terminal slightly so we could hook it to the ring terminal.

Slowly pull the wires up and out of the fuel pump access door.

When this step is finished, the pinned or ring terminal ends of both the White Power Wire and Blue Ground wire will be accessible inside the fuel pump access door. Both wires should run under the car and back into the car’s interior through the grommet under the rear seat.

Step 8: Stud Bypass Kit Installation

For metal fuel pump hangers, the thin black wire on the in-tank jumper harness will be trimmed as close to the terminal as you can. Leave this trimmed wire open and follow the rest of the installation instructions below.

Drill holes into the hanger for the stud kit

Do not use any other size than a 15/64th drill bit.

Install the Stud Kit Through the Hanger

It is VERY IMPORTANT that these pieces be installed in this order. You can damage the wiring kit and your car if this is not done properly. This is to seal the fuel tank but also ensure that the metal of the studs do no touch the metal of the hanger.

Your kit will likely have black insulators with a built-in washer, so there will only be 1 additional washer per stud (2 washers total included in the kit). The process is the same as what is shown in our installation video. We recommend putting the black insulator/washer combination sleeve on the bottom side of the hanger to help ensure the hanger is sealed well. The separate washer will go on the top side of the hanger.

Hooking Up Wiring to Stud Kit

Make sure to plug the OEM 6-pin connector back into the hanger once you install it to keep fuel level and fuel temperature working correctly.

Make sure that the blue wire is connected to the stud with the blue wire on it underneath, and make sure white matches up to white.

Section 9: Getting “Key On” Power to the Red Wire to Turn on the Relay.

Fuse choice will depend on the vehicle. If you are not sure which to tie into, please ask us! You will tie it into the in-cabin fuse box which is located on the driver's side of the car under the dash.

Please note that any “key on” power fuse will work for this. Accessory power or battery power tie-ins will not work and could damage your vehicle so please pick a KEY ON POWER SOURCE to tie into.

Fuse #13 for 2002-2007 Impreza models

Fuse #14 for 2004-2008 FXT and 1998-2001 Impreza

Using a pair of pliers, gently remove the fuse from #13 (or 14, depending on the model)

This image is shown outside the cabin for demonstration purposes only

Insert the fuse removed from the fuse box into the add a fuse provided in your FPC Hardwire Kit.

Insert fuse from fuse box into the add-a-fuse from the iWire kit.

Make sure you have 2 fuses in the add-a-fuse or the kit will not function

Insert the add-a-fuse back into the fuse box where you removed the original fuse (fuse #13 or fuse #14 location)

Connect the add-a-fuse to the small red wire running from the FPC jumper in the rear

Section 10: Reconnecting Battery/Power

Before completing the next step, be sure you have disconnected the negative terminal from your car’s battery, and that it remains disconnected. Also, be careful not to short the battery terminals with a metal tool or with your body.

Attach the red power wire that runs through the firewall to the positive terminal on the battery. There is a stud underneath the red boot on the battery’s positive terminal where the power wire ring terminal can be bolted down. One or more wires will already be connected to this stud. Simply remove the nut holding them on and slip the power wire ring terminal over the stud. Now thread the nut back on over the ring terminal and tighten it down.

Finally, slide the red boot back in place over any exposed metal. Reconnect the negative terminal on the battery. Now, it is time to test the system.

Step 11: Testing and Final Clean-Up

We always recommend testing the system before buttoning everything up.

To test the system, insert the key into the ignition and turn it to the “ON” position. Do not fully start the car. The fuel pump should turn on and then shut back off. If this is the case, start the car now. Congratulations! The installation is almost complete.

Go back to the trunk area and secure all wiring so that it is running out of the way and won’t move or get caught on anything in the car. Tighten down any cable ties that were left loose. Use additional cable ties to keep the wires neatly tucked together on the side of the trunk.

As always, installation is the reverse of removal, but here’s the order just in case you need a hand getting everything right.

Reinstall, in order:

The rear seat back support bracket and attached trunk-cabin separator trim
Trunk liner
Rear seat back (being careful to attach loops at the top of the rear seatback to the hooks on the chassis)
Rear driver’s side door sill trim
B-pillar trim
Front driver’s side door sill trim
Rear seat bottom
Washer tank in the engine bay

Troubleshooting

The most common failure is related to the fuel pump controller, so we suggest starting with the link below.

Fuel Pump Controllers Part 2 - Diagnostics

Thank you for purchasing the iWire Fuel Pump Hardwire Kit! We hope you enjoy our product. If you have any questions or feedback, please email us at info@iwireusa.com