Where should the flex fuel sensor be mounted in the fuel system?
Inline in a fuel line — but sources differ on which one.
- CPR Racing: inline in the fuel line before the fuel rail, where it measures the blend going to the engine.
- Syvecs: the sensor is designed for installation in the return line. Its straight 3/8 in (9.5 mm) tube adds little restriction and resists ethanol corrosion.
Follow the instructions for your sensor kit and fuel system (return vs returnless). See fuel, E85 & boost.
Confidence: medium — sources disagree or are limited; check the sources below.
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Sources
- Flex Fuel Sensor GM/Continental OEM E85 — CPR Racing
- Syvecs Flex Fuel Sensor — Syvecs