Skylark V6-173 2.8L VIN X 2-bbl (1984)
Distributor Vacuum Control: Description and Operation
Distributor Spark Vacuum Regulator Valve (DS-VRV)
This valve limits the spark vacuum to a calibrated value until ported vacuum applied to the control port of the VRV is greater than the calibration
value. When ported vacuum is greater than the calibration value, full manifold vacuum signal is applied to the distributor.
Manifold and ported vacuum is applied to the VRV through two distributor spark thermal vacuum valves (DS-TVV). Ported vacuum is available to
the VRV at all times with no vacuum control. When carburetor air inlet temperature is below the specified temperature, manifold vacuum is supplied to
the VRV through a distributor spark thermal vacuum valve (DS-TVV) and controlled by an inline distributor spark vacuum delay valve (DS-VDV).
DS-VDV maintains vacuum advance during quick throttle openings, improving engine response during cold engine operation. When engine coolant
temperature is above the calibrated value of the valve, full manifold vacuum is supplied to the VRV with no additional vacuum controls.
