Fuel Control

Fig. 1 Fuel System Diagram:

The electronic fuel injection "L" system can be divided into two systems connected at the injectors. The systems are:

A fuel system, Fig. 1, delivering a constant supply of fuel at the correct pressure to the injectors.

Fig. 2 Fuel System Components:

An electronic sensing and control system, Fig. 2, which monitors engine operating condition of load, speed, temperature (coolant and induction air) and throttle movement. The control system then produces electrical current pulses to hold open the injector solenoid valves and allow the correct quantity of fuel to flow through the nozzle for each engine cycle.
With a constant fuel pressure, varying the pulse duration increases or decreases the amount of fuel passed through the injector to comply with engine requirements. Pulse duration is also modified to provide enrichment during starting and warm-up and at closed throttle, full throttle and while the throttle is actually opening. All the injectors are simultaneously operated by the Electronic Control Unit (ECU) twice per engine cycle. The induction system is basically the same as that on a carbureted engine: tuned ram pipe, air cleaner, plenum chamber and induction ports. The air is drawn through a paper-element cleaner to a single throttle butterfly valve and to individual ports for each cylinder leading off the plenum chamber. The injectors are positioned at the cylinder head end of each port so that fuel is directed at the back of each inlet valve.