Flex Fuel Composition Sensor

Overview

The Haltech Flex Fuel Composition Sensor transforms your ECU into a true multi-fuel system, automatically detecting ethanol content from E0 to E85 and adjusting fuelling and timing maps in real-time. Essential for modern high-performance builds running flexible fuel setups, this sensor eliminates the guesswork and potential engine damage from incorrect fuel mapping across different ethanol blends.

Technical Specifications

• Part Number: HT-011000
• Fitting Type: 3/8" GM Spring Lock connections
• Ethanol Range: 0-100% (E0 to E85+)
• Output: Variable frequency signal to ECU
• Includes: Matching electrical connector and pins
• Wiring: Customer installation required

Why You Need This

Running different ethanol blends without flex fuel sensing is playing with fire—literally. E85 requires roughly 30% more fuel than petrol, plus different ignition timing strategies. Get it wrong and you're looking at lean conditions that'll melt pistons faster than you can say "knock". This sensor continuously monitors your fuel's ethanol content, feeding that data to your Haltech ECU so it can seamlessly transition between fuel maps. We see this constantly on LS swap builds, turbo RB engines, and modified SR20 setups where owners want the octane benefits of E85 for track days but need pump petrol flexibility for daily driving.

The GM 3/8" spring lock design is the industry standard—you'll find these fittings on everything from Corvettes to aftermarket fuel rails. The included connector and pins save the hassle of sourcing OEM GM parts, though you'll still need to run signal, power, and ground wires to your ECU. Professional installation ensures proper signal integrity and prevents fuel leaks in your engine bay.

ECU & System Compatibility

Compatible with the full Haltech Elite and Nexus range, including Elite 550/750/1000/1500/2000/2500 and Nexus R3/R5 ECUs. Your ECU firmware must support flex fuel functionality—contact our technical team to confirm compatibility for your specific setup and discuss the best mounting location for your application.

What's in the Box

• Haltech Flex Fuel Composition Sensor (HT-011000)
• GM-style electrical connector
• Connector pins
• Technical documentation

Complete Your Build

Most customers adding flex fuel sensing also require fuel system upgrades to handle E85's different flow characteristics and corrosive properties. Our technical team can specify the right fuel pumps, injectors, and fuel rail components for your specific power targets. With our UK stock holding and in-house tuning experience, we'll ensure your flex fuel system is properly calibrated from day one—contact us for application-specific advice and bundle pricing.