Part Number - Subaru CAN Gateway Flex Fuel Kit
Subaru WRX MT 2015-2021
Congratulations on your purchase of the COBB Tuning xxxxxxxxxxxxxx! The following instructions will assist you through the installation process. Please read them BEFORE beginning the install to familiarize yourself with the steps and tools needed. If you feel you cannot properly perform this installation, we HIGHLY recommend you take the vehicle to a qualified and experienced automotive technician.
Parts List
Tools Needed
Sockets
3/8"
3/8" ratchet
3/8" 12" extension
3/8" 6" extension
3/8" 10mm deep socket
3/8" 12mm deep socket
Misc.
Subaru Fuel LIne Disconnect Tool (Not Subaru specific but a size appropriate for a Subaru)
Stock component removal
Park your car in a flat, level area.
Discharge the existing fuel pressure from the system. Consult the factory service manual for OEM methods. One potential method is to disable the fuel pump by pulling the fuse on the driver's side of the engine bay (consult the underside of the lid for correct fuse location), then attempt to start the vehicle. The vehicle will likely run for a brief moment and stall. Fuel pressure is reduced by this method, but some pressure may remain in the system.
Once the vehicle stalls out due to loss of fuel pressure, allow it to cool down.
Using a 10mm disconnect the negative terminal of the battery followed by the positive terminal. Disconnecting the positive first can still cause things to be active as touching the connector to ground anywhere will allow it to connect. However disconnecting the ground first, means the chassis is no longer an integrated part of the electrical system and therefore the safer option.
Using your deep 1-mm or a wrench and some perserverence, undo the battery tie down, then remove the battery from the car.
Still with the 10mm, loosen the two bolts on the top of the fuse box.
Now remove the bolt on the bottom.
Moving on to the next section, use your fuel line disconnect tool to release the stock fuel line from the fuel rail near the intake manifold, as well as where it attached to the firewall. Once you remove one end some fuel may come out, so shielding it with a paper towl or similar is advisable.
Ethanol Content Sensor Installation
Install the fuel lines to the ethanol content sensor. The shorter of the two will go on the sensor side with the connector.
Orient the bracket so the fuel connections are on the top, and the electrical connection on the bottom, facing the engine. Use the smaller hole closest to the sensor so that the sensor doesn't hit the metal cover on the engine
The longer side should make it over to the firewall where you removed the fuel line earlier.
The shorter hose will go over to the engine side where you removed the fuel line. Make sure to snap the blue or white collar down to hold the fuel line in place. If installed properly, t shouldn’t easily pull off and will be easy to rotate freely. If installing the fuel pressure sensor, it will go between the engine side and this fuel line.
Gateway Module Installation
Install the gateway module to the bracket using the provided hardware.
Using a 12mm, loosen the nut on the stud of the passenger’s side strut tower.
Slip the open slot side of the bracket over the stud and rotate it down.
Using the provided bolt, attach the bracket to the strut tower, then tighten the nut on the other side.
Gateway Harness Installation
On the closer framerail in the engine bay you will see a large module. Directly beneath the large “High Power” connector you will find a small 5-pin conector. Squeeze the release tab and remove the connector from the module.
With this unplugged, you can install the jumper wires into the body harness, and then plug it back into the module.
Once the CAN side is plugged into the body harness, you can route the harness over and around to the top left Vehicle port of the gateway.
The two sensors can get plugged into either of the bottom ports on the gateway. They are self identifying harnesses so the module will detect which sensor is where.
Route the brown ethanol sensor connector across the intake manifold and under the engine cover or intercooler to plug into the ethanol content sensor you installed previously.
Route the fuel pressure sensor under the engine cover/intake manifold to plug into the fuel pressure sensor.
Final Prep and Reassembly
With everything plugged in, re-install your battery. (Make sure to wait until any fuel you spilt has dried before reconnecting to avoid a fire.)
Reinstall the fuse for the fuel pump.
Once the battery and fuse are reinstalled key the car on and then off again (without starting). After this cycle look over your fuel lines for any leaks. Repeat this process 3-4 times.
Once you’re happy with the fuel line situation, go ahead and start up the car. You’re all done!
CARB Sticker Application
(Where Applicable)
Apply the supplied CARB sticker in a clear, easy to find location. Typically underhood, or on the radiator core support.
Links
MAP Notes
Helps to figure out which map you should be on given the parts installed to your car
Links for related parts