Skylark V6-173 2.8L VIN X 2-bbl (1984)
Distributor Thermal Vacuum Switch: Description and Operation
Distributor Spark Thermal Vacuum Switch (DS-TVS)
This switch allows no vacuum flow to the distributor when engine coolant temperature is below the calibration temperature. When engine coolant
temperature is above the calibration temperature, the DS-TVS allows ported vacuum to the distributor. The ported vacuum signal is controlled by a
distributor spark vacuum delay valve (DS-VDV) which maintains vacuum advance during rapid throttle openings, thereby improving engine response
during cold engine operation.
