An eFlexFuel E85 kit typically includes everything needed to convert your vehicle to run on E85 safely:
- eFlexFuel Control Unit – the main controller that adjusts fueling automatically
- Ethanol content sensor – measures the ethanol level in the fuel in real time
- Vehicle‑specific wiring harness – designed to match your engine and injectors
- Vehicle‑specific fuel line connectors and fittings – required for installing the ethanol sensor
- Installation instructions – detailed guides to help with proper setup
- eFlexApp – lets you monitor ethanol level, system operation, fault codes, fuel logs, and other features directly from your smartphone
- eFlexTuner – allows advanced settings, fine‑tuning, diagnostics, and system configuration by installers and experienced users
Detailed preview of content
We will use an eFlexPro kit for example and review all the components.
- Your kit components may differ from those pictured below. This does not mean you are missing parts or received the wrong kit. These photos are for example purposes only.
- Plug types and sizes may differ depending on application.
- You may receive extra connectors with your kit - we like to include spares/options.
- The text in this guide corresponds with the photo directly above it.
eFlexFuel E85 Kit Overview
This is the full eFlexFuel eFlexPro kit pictured above. Below, we will dive into detail on the kit components.
Control Unit
- The eFlexFuel Control Unit is the "brains" of the eFlex kit.
- The Control Unit does exactly what you think - it controls eFlexFuel functionality.
- The Control Unit has a metal reinforced eyelet for secure mounting. Strong double sided tape and velcro are also commonly used for mounting.
- The Control Unit only has one plug - for the main eFlexFuel harness.
Main Wiring Harness
- The Main Wiring Harness joins the eFlexFuel Control Module, Ethanol Sensor and Vehicle Injectors together, allowing our system to work in conjunction with your vehicle's fuel system.
- The Main Wiring Harness has four hard-wired injectors and four optional injector extensions, allowing operation from 4-8 cylinders. Extensions are reviewed below.
- 4 cylinder applications MUST use the four injector wires off of the main harness.
- Some V8 applications will receive a wiring harness with eight hard-wired injectors (no extensions).
Optional Harness Injector Extensions
- Four Optional Harness Injector Extensions are included.
- These extensions are used to extend the main harness from 4 cylinders/injectors to 5, 6, or 8 injectors.
eFlexFuel Harness Injector Plugs
- The eFlexFuel Harness Injector Plugs (in red square above) are installed in the eFlexFuel harness after measuring injector polarity on the vehicle.
- The eFlex harness wires will clip into place in these plugs. No cutting or soldering is required.
Fuel Line Accessories Pack
- The Fuel Line Accessories Pack includes fuel hose, fuel hose clamps, various quick connectors, and a fuel line disconnect tool.
- Different applications will include different parts.
- Not all parts may be required - we like to include spares/options.
Ethanol Content Sensor
- The Ethanol Content Sensor real-time measures exact Ethanol % in your fuel over 100 times per second, allowing the eFlexFuel control unit to precisely adjust fueling no matter the Ethanol mixture.
- The Ethanol Content Sensor is installed with the fuel line accessories pack and plugs into the main wiring harness.
Bypass Module
- The Bypass Module is a "dummy plug" that can be used in place of the control unit for troubleshooting or if you ever need to remove your control unit.
- The Bypass Module is a passthrough that effectively returns your injector wiring to stock. Because of this, normal gasoline (E10) MUST be in your fuel system before plugging in the bypass module.
- The Bypass Module does NOT plug into your OBD - this is NOT an OBD plug.