FW build

Project uses WinAVR GCC compiler distribution, version WinAVR-20100110. Build is done by executing make command in project's root directory. You should check and edit path to compiler in makefile.

User interface

There are 3 LEDs and one button. After reset, one LED is on, indicating selected mode. Pressing button, you can cyclically select next mode:
Gas (green) - SW do nothing, output pulse is equal to input pulse. Cold start function is disabled.
E85 (yellow) - Width of output pulse is increased by 20% (default), E85 maps are used for crank condition.
E70 (red) - Width of output pulse is increased by 20% (default), different E70 maps are used for crank condition.

Cold start maps

When engine is cold, ethanol in E85 does not evaporate in compression phase inside engine. It stays in liquid form and do not burn at all. In this condition engine runs only on gasoline from E85 blend. You have to inject much more (twice as normal) fuel to get engine start.
If you turn power on and wait > 3s before start cranking, cold start function will be enabled. Cold start function uses temperature sensor and cold start maps to calculate additional enrichment for low temperatures. There are two maps - cranking map and enrichment map. Cranking map is used for the first 2s of run time and then enrichment map is selected. Maps are 2 dimensional arrays, X axis is temperature [C], Y axis is enrichment [%].
Third map is time table, it defines how long is cold enrichment applied after start. It is also function of temperature - the lower temperature is, the more time is used.

External temperature sensor

Eckit has build in temperature sensor, but it does not get temperature of engine. It works fine if you park your car at evening and next day engine && kit has same temperature. But if engine has different temperature (sunlight, warm engine etc), cold start function uses wrong temperature and engine will be to rich/flooded. You can connect second temperature sensor connected to cooling system / engine head. Sensor is plain 22kohm NTC.

Skoda Fabia problem (looks like all VW cars)

Eckit takes power supply primary from injectors. This works fine on many cars (fiat, mustang), but skoda takes power supply for injectors from fuel pump. This means, when you turn keys on, pump (pwr supply) runs only 1-2seconds and then is shut down. In this case, cold start can't be activated by waiting 3s before cranking - because car shuts power supply for eckit before engine starts cranking. In this case, you can use external temperature sensor with cold start function always turned on (code has to be modified). Or you can use new feature (circuit v 1.2) with power switch - eckit can be connected directly to battery through power switch. It is turned on when power supply appears on injectors, then eckit stays on even if injectors loses power. Switch is turned off if there is no signal on injectors for more then 30s. This disconnects eckit from battery and avoids draining power. This makes very easy to install kit into fabia, no need for invade car's harness.