Ethanol Parameters

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Ethanol control requires the addition of a flex fuel sensor and a control unit that outputs a 0 to 5 volt signal for ethanol percentage.




Input for ethanol control requires the for the signal wire from the ethanol control unit to be fed into the ECT2 pin and for ECT2 to be disabled in the software under the miscellaneous parameters.


Ethanol percentage defines the range of the signal from the ethanol control unit.  Most units use a 0 to 5 volt range where 0 volts is 0 percent ethanol and 5 volts is 100 percent ethanol.


The ECU ECT2 input has a pull up resistor to 5V internally, and some ethanol content devices cannot pull the output voltage down to give an accurate reading at low ethanol content percentages.  We recommend these settings:


Zeitronix ECA : 0.34 volts = 0%, 4.97 volts = 100% (will not read below 15% ethanol).

Innovate ECF-1, MTX-D, ECB-1 : 0.00 volts = 0%, 5.00 volts = 100% (will not read below 1.5% ethanol).


In the USA pump gas has 0 to 10% ethanol (typically 10%) and E85 fuel is 55-80%, depending on location and time of year.


Ethanol fuel compensation delivers more fuel based on ethanol percentage.


Ethanol ignition multiplier takes ethanol percentage and delivers a multiplier that is used to determine how much ignition should be added from the ethanol ignition compensation table.




Ethanol ignition compensation table is used in conjunction with the ethanol ignition multiplier table.  The final ignition value is the product of the value from the table and the ethanol ignition multiplier.  The result is added to the commanded ignition value of the engine.




Ethanol wot fuel compensation table delivers more or less fuel at WOT.  In testing, direct-injection vehicles were found to respond better to less fuel at WOT with higher ethanol content.  So a vehicle whose normal WOT air fuel is 11:1, would show better power and less knock at 11.8:1 air fuel with 85% ethanol.




Boost by ethanol limit table delivers more boost as ethanol increases.  The TC maximum pressure table should be tuned for full E85 and then limited by this table as ethanol comes down.