Open Loop Fuelling
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2004 Land Rover Discovery, 2003 Land Rover Discovery, 2002 Land Rover Range Rover, 2002 Land Rover Discovery, and 2001 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.
Open loop fuelling does not rely on information from the HO2S, but the air/fuel ratio is set directly by the ECM, which uses information gained from the ECT, MAF/IAT, the TP sensors and also the vehicle speed sensor (VSS). The ECM uses open loop fuelling under the following conditions:
- Cold start.
- Hot start.
- Wide open throttle.
- Acceleration.
The ECM uses open loop fuelling to control fuel quantity in all non adaptive strategy conditions. The ECM implements fuelling information carried in the form of specific mapped data contained within its memory.
Because there is no sensor information (e.g. HO2S), provided back to the ECM, the process is called an OPEN LOOP.
The ECM will also go into open loop fuelling if a HO2S fails.