CNG

This is normally an Open Loop mode on gasoline powered vehicles. On CNG powered vehicles, this is an Closed Loop mode. During wide open throttle operation, the Powertrain Control Module (PCM) receives the following inputs:
- Battery voltage
- Crankshaft position sensor
- Engine coolant temperature sensor
- Intake manifold air temperature sensor
- CNG fuel low-pressure sensor
- CNG fuel temperature sensor
- Manifold absolute pressure (MAP) sensor
- Throttle position sensor (TPS)
- Oxygen sensor (O2S)
- Camshaft position sensor (in distributor)
- Vehicle speed sensor

During wide open throttle conditions the following occurs:
- Voltage is applied to the fuel injectors with the PCM controlling injection sequence and injector pulse width. This is done by turning the ground circuit to each individual injector on-and-off at the PCM. The PCM also monitors O2S sensor input. It then adjusts air-fuel ratio as needed.
- The PCM adjusts spark advance as necessary for rpm, temperature and load. This is done for maximum power and efficiency