How your FFV really works

Octane Pro Antolin Chang Explains FFV Technology

Words: Antolin Chang, ​Antspec

Cover Photo: ​Jason Hoang​

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Does your vehicle have an FFV badge? A yellow fuel cap?

If it does, you should be filling up with a quality fuel like Propel Flex Fuel E85. Flex Fuel technology enables FFVs (Flex Fuel Vehicles) to run E85 as a primary fuel, or you can use it as a powerful and affordable octane booster.

With Flex Fuel technology, you can blend any amount of regular gasoline with Flex Fuel E85. You can enjoy the benefits of affordable and renewable fuel no matter where you fueled last. Running E85 is also cleaner, and makes a positive environmental impact with lower carbon and particulate emissions. As for performance, running E85 allows your car to produce better power in a cost-effective manner. Like magic!

Here’s how it works.

The typical Flex Fuel system consists of four main components: the ethanol sensor, the Ethanol Content Analyzer (ECA), the Engine Control Module (ECM), and the engine calibration. Let’s look at how these components work together.

“With Flex Fuel technology, you can blend any amount of regular gasoline with Flex Fuel E85.”
Antolin Chang

The Ethanol Sensor

The ethanol sensor is installed in the fuel lines of your vehicle and reports to the ECM exactly how much ethanol is currently in the fuel system. This allows you to use any ethanol blend you want. All you have to do is drive up, fill up, and drive off with confidence that this sensor is constantly watching over your fuel system. But before the ECM can use this signal, it has to be analyzed and translated. That’s where the ECA comes in.

The ECA — The Converter

The ECA, in its simplest form, is a signal converter. It takes the analog signal from the ethanol sensor and converts it into voltage that can be read by the ECM. This allows the ECM to understand the ethanol sensor so the engine calibration can be adjusted as needed. Some fancy aftermarket ECA’s will display the ethanol content for you as a percentage. Cool upgrade. Next up is the ECM.

The ECM — The Computer

The ECM is the computer that controls everything relating to the operation of your engine. Every vehicle has one. It controls how long the fuel injectors open, when the spark plugs fire, how much the turbocharger is boosted, stuff like that. All of those parameters reside deep within the ECM’s software. This leads to the final and most important part of any Flex Fuel system— the engine calibration.

Engine Calibration — The Controls

This is what makes your engine start in the morning and go when you step on the fun pedal. The engine calibration is the software that lets the ECM know what to do with all the signals it’s getting. This is what controls the hardware that makes your vehicle’s engine run.

Flex Fuel calibration is dynamically adjusted on the fly every time the ethanol sensor updates the ECM about your fuel system’s ethanol percentage. The system constantly checks and optimizes your engine calibration in real time according to the amount of ethanol in the fuel system. Refined, proven technology. Nice.​

These four magical components work together tirelessly to deliver an even and reliable driving experience no matter what ethanol blend you’re running. Fuel with confidence!​

ABOVE / The AntSpec Crew

AUTHOR PROFILE // Antolin Chang

With over 26 years of automotive industry experience, Antolin has a wealth of knowledge to help enthusiasts achieve their performance goals. Antolin was GM of COBB Tuning SoCal and now owns the shop under the AntSpec brand. He leads a team of highly-trained professionals out of his Fountain Valley, CA shop. His team’s passion for the industry drives them to create positive customer experiences and build a community of fellow enthusiasts.

10591 Bechler River Ave.

Fountain Valley CA 92708​


Facebook: @Antspectuning