Ethanol adaptation: Function

The engine can be run on all fuel mixtures from pure petrol to pure E85. This means that the ECM must learn the mixture to be able to calculate the correct injection quantity. The ethanol adaptation works in a way whereby the ECM looks at the lambda control and analyses the deviation from the zero point in order to determine the current ethanol content in the fuel.

If the vehicle is run on pure petrol and then refuelled with E85, then lambda sond 1 (before the catalytic converter) will indicate lean running. The lambda control is then increased (increasing fuel quantity), at the same time the recalculation factor is decreased from 14.7 to a lower value, minimum 9.8. This continues until lambda sond 1 indicates that a mixture ratio of lambda 1 has been obtained. The recalculation factor is a measurement of the current ethanol content in the fuel. 14.7 means pure petrol, while 9.8 means that the ethanol content is 85%.

If the vehicle is run on E85 and then fully refuelled with pure petrol then lambda sond 1 will indicate rich running. The lambda control is then reduced (decreasing fuel quantity) and at the same time the recalculation factor is increased from 9.8 to a higher value, maximum 14.7. Exactly as normal, the lambda control should fluctuate around the 0% line.