Can someone explain to me what this does? I thought it pushed vacuum to the lines to make the truck run.So I thought it may be clogged and took it out and wow it’s very different than I thought.
It is a thermal vacuum valve. They were used on just about all of the pre-electronic, computerized engine management systems, of just about all manufacturers. They controlled all sorts of things by vacuum on the engine on those later emissions, pre-computerization engine management systems. That valve could be hooked to anything that you didn’t want seeing vacuum until the car warmed up, or wanted to see vacuum only when the car was cold. The one on my Hijet hooks to One of the vacuum canisters on the distributor when the truck is cold, and to the other when the truck warms up. There are whole books on the vacuum driven emissions systems.
