Hondata

I have tested on the bench here and with nothing connected it will read 99% if you have Flash Fuel enabled. It sounds like you have either a wiring problem, or the flex fuel sensor is bad.

Ok. How do I test the out out of the sensor? Would I need to use a voltmeter with the ability to read frequency? I am getting 12v at the sensor so it has power, but i will double check the ground for continuity. Maybe I will try a chassis ground rather than the ecu and check back in.

You will need something that can detect frequency.

Ok, finally got a voltmeter that reads khz and I'm getting around .3khz testing between the signal and ecu ground which should be what the exu is getting and testing the positive on an0 and grounding the voltmeter lead I get as high as .85khz. either way, these are really high readings correct? Shouldn't I be seeing around .13-.14khz (130-140hz?). Maybe its a bad sensor?

50Hz=0%, 150Hz=100% Some sensors have an error condition with an output of 170-200Hz (from memory).

Ok, I will get another sensor. Strange that it worked for one minute then suddenly died. Is it possible my resistor between the power and signal wires failed or broke loose?

I'd say that there is a greater chance of it being the pull up resistor or wiring than the sensor.

Ok, the power source is good. The ground is good (should be since it's using the s300 ground. So I'll take apart the harness and check the resistor. What exactly is the function of that resistor?

The ethanol sensor output is open drain, so you need a pull up resistor to give it a waveform output.