Details
Bigas SGIS LPG Computer - Semi Sequential First Generation Gas Injection System with Integrated MAP Sensor
The Bigas SGIS computer is the very first model of Bigas gas injection systems and a semi-sequential or semi-sequential injection system. This LPG computer is unique because the MAP sensor (manifold absolute pressure sensor) is integrated into the ECU itself, rather than being mounted as a separate component. As a result, the computer has a pressure tube or vacuum tube protruding from the housing, to which the gas hose is connected for pressure measurements from the intake manifold.
Technical specifications
- Brand: Bigas
- Model: SGIS
- Type: Semi-sequential injection system
- Generation: First generation Bigas
- MAP sensor: Integrated in computer
- Pressure tube: Present for gas pressure measurements
- Operating mode: Stand-alone system
- Compatibility: K-Jetronic and mechanical petrol applications
Function and features
The Bigas SGIS system was mainly used on vehicles with K-Jetronic mechanical fuel distribution or other older systems. The great advantage of this LPG ECU is that it is a stand-alone system, which means it can function independently without signals from the original petrol computer. This is in contrast to modern master-slave systems, where the LPG computer receives signals from the petrol ECU to control the gas injectors. The SGIS system calculates the required injection time itself based on engine speed, gas pressure and vacuum in the intake manifold, measured via the integrated MAP sensor.
Installation and use
Mount the Bigas SGIS computer in a dry, vibration-free location in the engine bay or inside the vehicle. Connect the pressure tube to a vacuum line to the intake manifold with a thin vacuum hose or pressure hose. Connect the gas injectors, temperature sensor, pressure sensor (if external), RPM signal and other sensors according to the wiring diagram. As it is a stand-alone system, no direct connections to the petrol computer are needed. Calibration is done via a computer with diagnostic software to adjust the gas-air ratio and injection times.
Advantages
- Stand-alone operation without petrol computer
- Suitable for K-Jetronic and older systems
- Integrated MAP sensor for compact installation
- First semi-sequential Bigas system
- Reliable and simple design
- No master-slave dependency