Flexible Fuel Vehicle (FFV) ME function - GF07.61-P-3021P
ENGINE 112.946 in MODEL 203 as of 15.7.02 with CODE (929) Flexible Fuel Vehicle (FFV)
FFV-vehicles can be fueled with premium fuel or with Ethanol (portion of Ethanol 85 %). This results in mixtures with a portion of ethanol in the fuel tank from %0% to %85%
If at least 5 liters are refueled and if afterwards at least 10 liters are in the fuel tank, the teach-in process to identify the new fuel mixture is released via the signal of the fuel level sensor in the ME control module. In addition the signals of the oxygen sensor upstream TWC are directly evaluated after fueling.
If for example Ethanol was refueled, the mixture is at first too lean (oxygen sensor voltage jumps back to 0 Volt). The lambda control reacts with enriching the mixture for so long, until after fueling λ =1 is again achieved.
The required factor is taught in as Ethanol factor and is 1.0 for premium fuel and 1.43 for an Ethanol portion of 85 %-. The Ethanol factor acts multiplicative on the quantity injected and leads to a self adaptation of the mixture formation. The Ethanol factor remains effective, until after the following fueling a new value is learned.
The determination of the Ethanol factor lasts approx. 8 minutes when engine is warm. Rough learning takes place in neutral. During the following drive precise learning takes place (Prerequisite: Engine load larger than 30 % and rotational speed larger than 1400 1/rpm).
FFV vehicles are equipped with the fuel injection and ignition system (ME2.8.
The engine control module has the following additional functions:
- Teach-in process to identify the fuel mixture in the fuel tank after fueling
- Ethanol factor from 1.0 to 1.43 for mixture adaptation
- The message "last taught in Ethanol portion", indicates the Ethanol portion from the last conducted teach-in process. This value is irrespective from the Ethanol factor. If for example the Ethanol portion in the fuel tank is less than 18 % the Ethanol factor remains 1.0.
- Number of Ethanol teach-in procedures - the value indicates, how often an Ethanol portion of more than 30 % was learned.
- The message "Ethanol operation" indicates, that the Ethanol portion in the fuel tank is more than 18 %.
- The message "teach-in process" indicates, that the teach-in process is active at this moment and the fuel mixture in the fuel tank is not yet identified. When the teach-in process is active, the mixture adaptation and the regeneration is locked.
The message "exhalation procedure terminated" indicates, that the teach-in process is again released. During the exhalation of Ethanol out of the engine oil (engine oil temperature approx. 40 - 85° C) the teach-in process is locked. The exhalation procedure is only released, if beforehand an Ethanol portion of more than 60 % was learned.
The injection valves for FFV vehicles have a larger bore (red color marking). Corresponding to the Ethanol portion, the quantity injected must be increased, because Ethanol has a lower energy density than premium fuel.
The fuel ventilation line has a diameter of 10 mm instead of 8 mm, because Ethanol has a stronger gassing rate.
Repair instructions for FFV vehicles
Before starting a repair it is necessary to read out the adaptation values of the mixture adaptation, the Ethanol factor, the last taught in Ethanol portion and the number of Ethanol teach-in procedures.
Example 1 :
If during a repair the voltage supply to the engine control module was interrupted, if the engine control module was replaced or fuel refueled, afterwards release the learn mode with the STAR DIAGNOSIS.
Example 2:
If the number of Ethanol teach-in procedures is larger than zero and if a mixture adaptation is required after a repair, premium fuel should be refueled, so that the mixture adaptation can be conducted without Ethanol influence. After changing fuel, release the teach-in process with the STAR DIAGNOSIS.
When using premium fuel it is guaranteed, that for example faults due to unmetered air or a defective hot film mass air flow sensor is not learned as Ethanol portion.
| ME-SFI control module position / task / design / function | GF07.61-P-5000F | ||
| O2 sensors, location/task/design/function | GF07.04-P-4103F | ||
| Fuel tank location/design/function | GF47.10-P-3000P | ||
| Fuel injector, location/task/design/function | GF07.03-P-5004F |