wrightjt2007
Junior Member
- Joined
- Jun 29, 2025
- Posts
- 26
- Reaction score
- 4
- Location
- Georgia
- First Name
- James
- Truck Year
- 1983
- Truck Model
- K10 silverado
- Engine Size
- 305
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The short answer is everything. The gray TVS on the thermostat housing is for the Trapped Vacuum Spark, (TVS also abbreviated this way, for more confusion). That gives full vacuum advance when the engine is cold.I know that the thermal vacuum switches (TVS) controll a lot of stuff like opening and closing stuff. So in summary my main concern is what all has deleting emissions messed with.
no i dont have emissions where i live. I honestly want to know what i need to add back, how to add it back and, and stuff like what check valves i need to add with it.The short answer is everything. The gray TVS on the thermostat housing is for the Trapped Vacuum Spark, (TVS also abbreviated this way, for more confusion). That gives full vacuum advance when the engine is cold.
The other TVS controls vacuum for the EGR, the heat riser and more. The charcoal can has a purge valve that also uses ported vacuum. I don't know what port that is on the Edelbrock. If the charcoal can has sucked in raw fuel, it will melt the charcoal, clogging it all up. I'm guessing you don't have emissions inspections where you live.