Flex Fuel Sensor input :
- write in the WebShop order comment "wheelspeed2 frequency input needed for Ethanol sensor".
- firmware can be configured to automatically compensate for the Ethanol content based on the sensor readings. (First used by: MembersPage/Sascha )
This GM / Siemens Fuel Composition Sensor(FCS) current: GM12570260 EOL sensor: 12570250
Hard to find connector available here: [HU Webshop Ethanol Sensor Connector]
or: [US Webshop Ethanol Sensor Connector]
And a how-to on setting up display in VemsTune is available: [VemsTune FlexFuel Setup Guide]
Sensor reads in Hz.
Basic sensor testing:
- Freq stability check:
- Freq. vs input voltage changes:
- 5.5 VDC power supply, Freq. = 69.99 Hz raised up the power supply voltage in 1 volt steps to 16.0 VDC power supply, Freq. = 69.99 Hz
Note, sensor stops operating below 5.5 VDC. 16 VDC was the upper end of testing.
- Current draw at power supply voltages from 5.5 VDC to 16 VDC:
- 25.7 ma to 25.9 ma or .026 amps!
- Connections on sensor:
- Black is GROUND (Ohm to chassis to prove).
- Pink is 12VDC. (car battery)
- White is the output signal. (A pull up resistor is needed here because the output is an open collector transistor inside the sensor so any voltage interface will work)
| Hz | gasoline | Ethanol | Wheel Speed Reading km/h |
| 50 | 100 | 0 | 8 |
| 55 | 95 | 5 | 9 |
| 60 - E10 | 90 | 10 | 11 |
| 65 | 85 | 15 | 12 |
| 70 | 80 | 20 | 13 |
| 75 | 75 | 25 | 14 |
| 80 | 70 | 30 | 15 |
| 85 | 65 | 35 | 16 |
| 90 | 60 | 40 | 17 |
| 95 | 55 | 45 | 18 |
| 100 | 50 | 50 | 19 |
| 105 | 45 | 55 | 20 |
| 110 | 40 | 60 | 21 |
| 115 | 35 | 65 | 22 |
| 120 | 30 | 70 | 23 |
| 125 | 25 | 75 | 24 |
| 130 | 20 | 80 | 25 |
| 135 - E85 | 15 | 85 | 26 |
| 140 | 10 | 90 | 27 |
| 145 - E95 | 05 | 95 | 28 |
| 150 | 00 | 100 | 29 |
- 50hz is 0.5v, 150hz is 4.5v 0-100% ethanol
- and the pulsewidth of the input is the temperature of the fuel.
- temp formula is ?C = (41.25 * pulsewidth_in_ms) - 81.25
170Hz is error output (self diagnostics built into sensor)
With anytrim function
- the wheelspeed2 (0-255) can be also used as input (since ~1.1.8x firmware). The wheelspeed2 (which is a freq input) can be used for the Ethanol-concentration sensor.
- wheelspeed1 also but the Ethanol-sensor should normally be connected to wheelspeed2:
- please write in the WebShop order comment "wheelspeed2 frequency input needed for Ethanol sensor".
- also analog input, MAP or fuel pressure (which is 700 kPa absolute pressure analog input - MAP) can be useful for anytrim compensations
[external link for sensor] (config settings not relevant)
TODO: Flex fuel configlet to set multiple config options with 1 click (also: update VT help)
Speed sensor settings for flexfuel guide works:
- Speed sensor trigger edge : Falling
- Speed sensor divider : 10
- Speed Sensor Calibration : 10
In anytrim the road speed is always +50 to actual ethanol content so tuning is from 50kmh - 150kmh representing 0-100% Ethanol content.
Is it possible to develop V3 so that Speed Sensor settings allow to designate which speed input is Flex Fuel (which then automates these settings)
- and an actual Flex Fuel option is then available in anytrim
- a configlet to set a few variables in 1 step should be fine. Thanks for the feedback
At the same time fuel temperature which is represented by duty cycle could also be implemented as fuel temp and also allowed in anytrim as fuel correction. Just two channels that would make a world of difference in user approach to flex fuel and working with varying fuel temp for proper fuel amount calibration.
This would allow anytrim fuel, ignition and boost control to be reflected by actual ethanol content channel.