Cold Start Spark Advance System: Operation

System provides manifold vacuum to distributor advance, through the DRVC and CSSA PVS, when engine coolant is below 128°F (53°C). When coolant temperature is between 128-235°F (53-113°C), vacuum reaches distributor from carburetor spark port through the cooling PVS, SDV, and CSSA PVS. When engine coolant is above 235°F (113°C), manifold vacuum is applied to distributor advance through SDV and CSSA PVS.