The following article discuss on L-Jetronic Fuel Injection Systems for BMW E12 which covers following topics: Basic Engine Combustion Process, Combustion Requirements, Fuel Delivery Implementations, Electronic Fuel Injection System Components, L-Jetronic System, Troubleshooting, Conversion to Lambda Control, and Performance. The fuel injections system consist of throttle and idle/WOT switches, Air Mass Measurement, Fuel Pump, Fuel Injectors, Pressure regulation, Control Unit (some with O2 control), Combo Relay, Cold Start, Warm up enrichment, Warm up Idle compensation.
The L-Jetronic System – Control Unit (ECU) takes sensor information such as AFM flow and temperature, Engine RPM (from ignition), Warm up information (from coolant temperature sensor), Throttle mode (idle and WOT switches), O2 sensor in Lambda systems. Then calculates opening duration of injectors. This ‘map’ is hardwired into system (there’s no chip available to modify).