BMW 535i & Z4 Bluetooth Flex Fuel Kits for the E Chassis N54 Motors

Stop Guessing. Start Knowing Your Exact Ethanol Content.

Running E85 on your N54 powered BMW 535i or Z4? Ethanol content at the E85 pump can vary from E50 to E85 or higher depending on season and station. Regular premium gas can have up to 10% ethanol at some stations. No more calculating gallons at the pump and guessing ethanol percentage. Just open the app and know.

Key Features

• Real-time ethanol content monitoring via Bluetooth
• Displays exact ethanol percentage (E-content) in the Fuel-It! or JB4 app
• 0–5V analog output for JB4 or flash tuning integration
• Genuine Continental ethanol sensor for OEM-grade accuracy
• Plug and play fuel line integration
• Ethanol safe PTFE fuel lines and fittings
• Installs in approximately 30 minutes
• No cutting or permanent modification required

Why You Need an Ethanol Sensor

E85 pumps rarely dispense true E85. Seasonal blends can drop into the E50 range without notice. If you’re tuning for ethanol, this matters.

With this kit you can

• Dial in your exact E85 blend every fill-up
• Avoid running too much ethanol on a pump gas map
• Maximize timing and boost safely on ethanol maps
• Maintain consistent performance at the track
• Protect your engine from unknown fuel mixtures

The Bottom Line

If you’re running E85, a flex fuel sensor isn’t optional, it’s essential.

Power, consistency, and safety all start with knowing exactly what’s in your tank.

Vehicle Fitment

BMW 5 Series
• 2008-2010 E60 BMW 535i Sedan including xDrive
• 2008-2010 E61 BMW 535i Touring including xDrive

BMW Z Series
• 2009-2016 E89 BMW Z4 sDrive35i and Z4 sDrive35is

Download the Fuel-It! ECA app here:

For your fuel line upgrade, choose the option that supports your current configuration.

• HPFP to the fuel tank: (Stock)
• This upgrade replaces both stock fuel lines with one upgraded continuous fuel line from the fuel tank to the HPFP and adds the ethanol sensor.

• Port Injection to the fuel tank:
• If you are running our port injection kit, this upgrade replaces the stock fuel lines from the tank to the engine bay, integrates the ethanol sensor and then utilizes a Y adapter to supply the HPFP and PI with fuel. Our custom fittings remove those tee's and extra fittings for a cleaner high flow setup.

• Phoenix Racing Manifold to the fuel tank:
• If you are running the Phoenix Racing Manifold port injection kit, this upgrade also replaces the stock fuel lines from the tank to the engine bay, integrates the ethanol sensor and then utilizes a Y adapter to supply the HPFP and PI with fuel. Our custom fittings remove those tee's and extra fittings for a cleaner high flow setup.

• Non-Fuel-It! port injection to fuel tank:
• Choose this option if you are running a port injection kit that we did not manufacture or sell. This kit includes a longer 18" feedline from the Y to the port injection rail. You then cut the feed line to the length you need and install the included -6an female fitting or -6an female elbow to make the connection to your port injection rail.

All of our kits utilize our custom billet aluminum fittings to integrate with the stock fittings so no modifications are needed.

*For the BMW N54 E-series JB4 platform connect the white wire to position #15 on the JB4 25 pin harness. Select WMI Ethanol Setup option 1 to enable pin location 15/16 flex fuel input.

*For the BMW N55 E-series JB4 platform connect the white wire to position #16 on the JB4 25 pin harness. Select WMI Ethanol Setup option 1 to enable pin location 15/16 flex fuel input.

Vehicle fitment