PCM and Innovate ECF-1 flex fuel gauge with one sensor
04-17-2017, 02:32 PM
#1
PCM and Innovate ECF-1 flex fuel gauge with one sensor I am hooking my CTS-V up for flex fuel and purchased an ECF-1 to handle wideband and give me a nice place to see the ethanol content of the fuel when I fill up so I can adjust my boost controller accordingly.
The ECF-1 has 0-5v analog outputs for the ethanol content and fuel temp, but the P59 PCM is expecting the raw digital signal from the flex fuel sender itself. Is it possible to just split the wire from the flex fuel sensor to the ECF-1 and the PCM and have both of them read the output of the sensor? Or will I have to run 2 sensors in the car?
Thanks!
The ECF-1 has 0-5v analog outputs for the ethanol content and fuel temp, but the P59 PCM is expecting the raw digital signal from the flex fuel sender itself. Is it possible to just split the wire from the flex fuel sensor to the ECF-1 and the PCM and have both of them read the output of the sensor? Or will I have to run 2 sensors in the car?
Thanks!
04-17-2017, 03:02 PM
#2
I found a megasquirt article about these sensors, it says
So what I gather from this is both the ECF-1 and the PCM will be supplying 5v that is pulled to ground by the sensor in a square wave to make the signal. So worst case scenario the pull-up resistors in the PCM and ECF-1, when added together, would cause the amperage drawn through the sensor to be too high? Or is this negligible. Or am I thinking about this the wrong way? I never had any electrical engineering classes 
The fuel sensor uses a microprocessor to measure the ethanol percentage and fuel temperature, which it uses to produce and output signal. The fuel sensor signal is a square-wave voltage signal. The signal varies in both frequency and pulse width:
The frequency of the signal indicates the ethanol percentage. The output frequency is linear with respect to the percentage of ethanol content in the fuel. The PCM provides an internal pull-up to five volts on the signal circuit, and the fuel sensor pulls the 5 volts to ground in pulses. The normal range of operating frequency is between 50 and 150 Hertz:
50 Hertz indicates 0% ethanol, and
150 Hertz indicates 100% ethanol.
The pulse width indicates the fuel temperature. The normal pulse width is between 1 and 5 milliseconds:
1 millisecond indicates -40°C (-40°F), and
5 milliseconds indicates 125°C (257°F).
The frequency of the signal indicates the ethanol percentage. The output frequency is linear with respect to the percentage of ethanol content in the fuel. The PCM provides an internal pull-up to five volts on the signal circuit, and the fuel sensor pulls the 5 volts to ground in pulses. The normal range of operating frequency is between 50 and 150 Hertz:
50 Hertz indicates 0% ethanol, and
150 Hertz indicates 100% ethanol.
The pulse width indicates the fuel temperature. The normal pulse width is between 1 and 5 milliseconds:
1 millisecond indicates -40°C (-40°F), and
5 milliseconds indicates 125°C (257°F).
05-14-2017, 06:50 PM
#3
I went ahead and threw caution to the wind and it looks like it is working fine wiring one flex fuel sensor to both the gauge and the pcm. Both are reading the same ethanol content.