How eFlexFuel works?

eFlexFuel controls fuel delivery

eFlexFuel working princible

The operating principle of the eFlexFuel is based on processing the fuel injection signals received from the car’s engine’s electronic control unit (ECU). As a result, the fuel injection is entirely controlled by the eFlexFuel conversion kit and car’s each fuel injector is controlled separately. Therefore, eFlexFuel adapts perfectly to different fuel injection schemes.

Changing the injector opening time

Since the energy content of E85 fuel is lower than that of regular gasoline, more needs to be injected during each injector cycle. Typically, the increase in the amount injected is about 28%. This amount decreases with increasing gasoline content of the fuel mixture. This regulation is done automatically by eFlexFuel.

Adaptive system

eFlexFuel recognizes ethanol content of the fuel mixture automatically and modifies the fuel injector signals accordingly. In this way, the air-fuel ratio is always optimal and fuel consumption, and emissions are minimized. When refueling, mixture recognition is done automatically if it has changed. This process is described in more detail in the manual.

Operating principle

eFlexFuel use ethanol sensor to recognize the fuel mixture. Recognition happens in real time and operation is fully automatic at all times. We use same ethanol sensor used by car manufacturers in factory-made flexfuel vehicles.

eFlexFuel adapts to the ambient temperature

eFlexFuel is equipped with an external temperature sensor that is used for adapting the device operation in accordance with the engine’s temperature. This will enable engine start in all climatic conditions such as in extreme cold weathers which is normally more difficult for the E85 fuel. The temperature adaptation is active only during engine start. eFlexFuel has been tested in temperatures as low as -30 °C (-22 °F). As compared to the use of bare gasoline, however, the use of E85 can result in worse cold starting capability in extreme cold weather.

Adaptive cold start function

eFlexFuel learns from failed cold start. Latest device version includes adaptive cold start function. This feature allows better cold starting with all types of vehicles and fully automatically.

Notice! Possibly weaker cold start ability is a result of significantly higher ethanol content of E85. eFlexFuel automatically adds fuel feed linearly when engine block temperature is low to ease cold starting.

Cold start aid

There are numerous ways to improve engine cold starting when E85 fuel is used in extreme cold weather. The best and the most economical way is to use an engine block heater. If such is not available, we recommend to add 5 - 10 % of regular gasoline to the E85-based fuel mixture.

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Check the compatibility for your vehicle

eFlexFuel is not available in direct injection engines (CGI, FSI, GDI, EcoBoost, etc.) or diesel engines.

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Carmake Model Start Year End Year Displacement Power (kW) Cylinder count Engine code

Not compatible to following engines:

Carmake Model Start Year End Year Displacement Power (kW) Cylinder count Engine code

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  • Manufacturer
  • StepOne Tech Ltd
  • Myllyhaantie 7
  • 33960 Pirkkala
  • Finland
  • FI24890300

eFlexFuel™ is developed and made in Finland

eFlexFuel™ is trademark owned by StepOne Tech Ltd