900 L4-1985cc 2.0L SOHC (1988)
Fuel Distributor: Description and Operation
Fig. 2 Fuel Distributor with Frequency Valve
The fuel distributor, Fig. 2, distributes the fuel to the individual injectors and consists of a fuel control unit and four pressure regulating valves, one for
each cylinder.
The skirt of the control plunger is in constant communication with the line pressure, which also acts on the bottom of the pressure regulating valve.
When the control plunger is raised by the lever from the air flow sensor plate, four metering slots, which feed the fuel to the top of the pressure
regulating valve, will be opened. The pressure above the spring loaded diaphragm acts upon the diaphragm, forcing it downwards and opening the outlet
to the injectors. A pressure differential of 1.5 psi (0.1 bar) is maintained between the line pressure and the control pressure acting on the top of the
diaphragm. This constant pressure differential is necessary to ensure that the injected quantity of fuel always remains proportional to the open area of the
metering slots, measuring the fuel quantity equally to all four injectors.
