Colt L4-089 1468cc 1.5L VIN K 2-bbl (1988)
Slow Cut Solenoid Valve: Description and Operation
Solenoid Valve Locations
This valve is located in the carburetor float chamber cover.
Solenoid Valve Duty Cycle
The ECU controls the air-fuel ratio by controlling the duty cycle of the valve. The frequency of ON-OFF cycles remain constant at 10 Hz pulses, but
the solenoid "ON" time portion of each cycle is changed to modify the duty ratio. The higher the duty ratio (the longer the ON time), the leaner the
air-fuel ratio.
Slow Cut Solenoid Valve (SCSV)
The SCSV controls the amount of air allowed to bleed into the idle jet and transition port fuel feed passage. When the SCSV is de-energized, the slow
fuel passage vent is closed, and the idle and transition circuits operate normally. When the SCSV is energized, the slow fuel vent passage is opened.
This allows a much larger amount of air into the passage effectively shutting off the fuel flow. With the ON-OFF operation (duty cycle) of the SCSV,
the air-fuel ratio is controlled.
