Stormhawk
Junior Member
- Joined
- Oct 4, 2024
- Posts
- 14
- Reaction score
- 33
- Location
- Scobey, Montana
- First Name
- Marshall
- Truck Year
- 1983
- Truck Model
- K20
- Engine Size
- 350
Damaged Mystery Component
- Thread starter Stormhawk
- Start date
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74Blaze
Full Access Member
- Joined
- Oct 25, 2022
- Posts
- 163
- Reaction score
- 627
- Location
- Nashville, IN
- First Name
- Gerald
- Truck Year
- 1974
- Truck Model
- K5/Blazer
- Engine Size
- 350
Looks like Cruise Control Valve...
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Stormhawk
Junior Member
- Joined
- Oct 4, 2024
- Posts
- 14
- Reaction score
- 33
- Location
- Scobey, Montana
- First Name
- Marshall
- Truck Year
- 1983
- Truck Model
- K20
- Engine Size
- 350
Doubtful. Truck doesn’t have cruise control. Looks like some dumb emissions nonsense. I bypassed it and the truck seems to be running fine without it.
JD Miller
Full Access Member
- Joined
- Sep 30, 2024
- Posts
- 359
- Reaction score
- 660
- Location
- Goober Idaho
- First Name
- JD
- Truck Year
- 1981
- Truck Model
- K20 silverado
- Engine Size
- 350
Smog crap, file it in the trash can
- Joined
- Aug 9, 2020
- Posts
- 81
- Reaction score
- 89
- Location
- US
- First Name
- Mike
- Truck Year
- 1983
- Truck Model
- K20 Suburban
- Engine Size
- 350
That is GM part #1997479. Its available from this guy. https://www.ebay.com/itm/326166939571
Ricko1966
Full Access Member
- Joined
- Apr 11, 2017
- Posts
- 5,606
- Reaction score
- 9,140
- Location
- kansas
- First Name
- Rick
- Truck Year
- 1975
- Truck Model
- c20
- Engine Size
- 350
It locks out vacuum advance in a couple of situations. It locks out vacuum advance on warm engines until you hit 3rd gear.It allows regular vacuum advance cold or if overheating. I'd run the vacuum advance can to manifold vacuum and cap the vacuum lines at the carbureator and air cleaner. Time the engine where it runs best. If it pings at part throttle warm, post back we'll work out a solution. Ignore the I time mine at 8-12-16 etc. Comments, time it where it runs best. Different engines,different wear,timing chain stretch,different factory distributor configurations, means what works best on one engine isn't necessarily what your engine needs.
Last edited:
David King
Full Access Member
- Joined
- Jun 19, 2023
- Posts
- 185
- Reaction score
- 264
- Location
- Crestview Fl. 32539
- First Name
- David
- Truck Year
- 1985
- Truck Model
- C-10
- Engine Size
- 305
Appears to be a badly damaged TVS (Thermal Vacuum Sensor) used with the A.I.R. (Air Injection Reaction) system.
