The Kit Stargas Injection System is a retrofit kit characterized by electronic management, with "Master / Slave", the injection of gas to power vehicles with spark ignition engines, built by STARGAS srl.
  The ECU Gas intercepts the signal to open the petrol injectors (Tj petrol) sent from the original petrol ECU. The microprocessor present in the ECU GAS, processes this data and generates the opening command of the GAS injectors (Tj gas). Some signals, sent from the sensors installed with the GAS conversion kit, are used by the algorithm for calculating the ECU Gas to improve the accuracy of the "Tj gas" calculated.
  Then the control unit Gas becomes an element "Slave" compared to the petrol ECU (element "Master") is not causing any disturbance signal input to the Petrol ECU that may adversely affect operation.
   Thanks to this principle of operation, the ECU Gas, allows the injection in the intake manifold, only the amount of gas, is strictly necessary to constitute the volume of the mixture intended for the individual cylinder. This, together with the location of connection of the injection immediately upstream of the intake valves, in fact prevents any accumulation of gas in the manifold avoiding any danger of explosion with consequent damage of the same.

The EOBD (European On Board Diagnostic) is always active during the gas functioning. In case of failure of components of the gas system which affect the polluting emissions, the gas ECU instantaneously commands the switchback of the fuel to petrol and memorises the event. This can be read by the installer to formulate a correct diagnosis of the breakdown. The automatic switchback to petrol following the failure is displayed on the quadrant of the changeover switch (see paragraph “Display of change-over switch”).


Some versions of the control unit allow connecting to the car’s original OBD system (On-board diagnostics).


The Taurus retrofit system is activated/deactivated by simply pressing the special switch located on the changeover panel. The user can give two commands:

1.     the change-over to petrol

2.     the pre-selection of the changeover to gas.


The first command allows changing the engine fuel from gas to petrol. This is carried out instantaneously by the gas ECU and involves closing the solenoid valves for the gas interception, deactivating the gas electro-injectors, reactivating the petrol injectors and deactivating their emulation function.

The second command allows changing the fuel of the engine from petrol to gas. It is carried out by the gas ECU on condition that the temperature of the engine’s cooling liquid is higher than a pre-set value (changeover temperature). This guarantees complete gasification of the LPG, which is necessary for correctly supplying fuel to the engine and for respecting the limits of the polluting emissions established by the current standards. During the changeover, the gas electronic control opens the solenoid valves for the gas interception, activates the gas injectors, and deactivates and emulates the petrol injectors.

Therefore, upon changeover, the opening of the solenoid valves allows the liquid gas to flow in pressure from the tank towards the vaporizer. The pressure of the liquid LPG is reduced in the vaporizer with the subsequent vaporisation. This is completed by taking heat from the liquid of the heating circuit in the passenger compartment. The gaseous LPG is therefore taken to the electronic injection unit, which commanded by the gas ECU, determines the gas dosage to go to the engine. In any type of operating condition, the quantity injected is calculated by the  gas ECU that processes the injection times of the petrol ECU (according to a master/slave operating scheme) and generates the command for opening the gas electro-injectors.

The gas ECU memorises the fuel mode set by the user on the changeover panel. 
The last fuel mode is kept even after the engine has been turned off and is re-proposed on the next start-up. In any case, the engine always starts on petrol.