Flex fuel 171hz

EMU BLACK / CLASSIC
1

Hi,

I have a problem with two brand-new Continental Flex Fuel sensors (980256380-A) connected to an ECUMaster EMU Black V3.

Both sensors behave exactly the same.

The sensor is connected to the dedicated Flex Fuel In, black connector pin 9:

  • Vcc → +12 V

  • GND → Sensor Ground

  • OUT → Flex Fuel In, pin 9

The EMU now correctly detects the signal and constantly shows:

  • FF Sensor frequency: 171 Hz

  • Fuel temperature: 20°C

However, the frequency does not change at all when I change the liquid flowing through the sensor.

I tested it with gasoline and brake cleaner, but the frequency remains exactly 171 Hz. The reported fuel temperature also remains at 20°C.

I also checked the signal with an oscilloscope directly at ECU pin 9. It is a clean square wave of approximately:

  • 0–4.9 V

  • 171 Hz

The important thing is that I have two brand-new sensors, and both behave exactly the same way. Because both are new and produce the same result, I don’t think both sensors are faulty.

Is there something specific that needs to be done to activate/configure the Continental sensor, or is there a specific test procedure to verify whether the sensor is actually detecting ethanol content and fuel temperature?

Could the constant 171 Hz indicate that the sensor is powered correctly but is not actually measuring the fluid, or that there is a wiring/configuration issue?

Thanks.

2

Could be that you need to run some actual e85 into the sensor to read it. I am not on V3 (because I’m not a fan of it yet) but my log under “FF sensor frequency” reads ~86Hz with 91 pump gas and then gets up to 125-130Hz with around 75-80% ethanol.

Fuel temp also reads correctly through my sensor as well.