454 vacuum line question

[Slooptin]

Ok, I'm re-installing my Q-Jet in my truck and had some questions about vacuum line routing. I'm trying to follow the vac diagram, but it isn't matching how this truck came to me or really making a ton of sense (I'm a carb novice). the PO also disconnected everything from the charcoal canister. With that being said, my questions are:

1. I have the red circled port (port B on diagrams) attached to the primary choke vacuum brake (not installed yet) and to the distributor. Is that correct?

2. Green (port H) and blue (unlabeled) are a mystery to me. where are they supposed to be hooked up if the cannister is off? Port T (above the blue one) was also left open. is that ok?

3. There is a sensor(?) attached to the thermostat housing that looks like it has three vacuum ports on it (second pic). What is it, and is it supposed to be attached to anything?

Thanks in advance for any assistance!

 

[Bextreme04]

1. Yes that connector looks like the right one for the pull-off.
2. Blue looks like a continuous manifold port that would be for the charcoal canister. Green is likely a manifold port that would go to #3 discussed more in depth below. The large port above the blue circle is for the PCV hose, it absolutely should NOT be left open and it needs to go to the PCV valve in the passenger side valve cover.
3. That is called a TSV(Thermostatic switching valve). It is for emissions to block off emissions equipment like the EGR and vacuum advance on the distributor until the engine warms up. They are expensive(~$20-$70 depending on the specific switch) and break often, so most people have just removed them and plugged the hole. Yours has the feed nipple on top broken off, which is likely why it has nothing connected to it anymore. You can find them at parts stores as "Ported vacuum switches".

 

[Slooptin]

1. Yes that connector looks like the right one for the pull-off.
2. Blue looks like a continuous manifold port that would be for the charcoal canister. Green is likely a manifold port that would go to #3 discussed more in depth below. The large port above the blue circle is for the PCV hose, it absolutely should NOT be left open and it needs to go to the PCV valve in the passenger side valve cover.
3. That is called a TSV(Thermostatic switching valve). It is for emissions to block off emissions equipment like the EGR and vacuum advance on the distributor until the engine warms up. They are expensive(~$20-$70 depending on the specific switch) and break often, so most people have just removed them and plugged the hole. Yours has the feed nipple on top broken off, which is likely why it has nothing connected to it anymore. You can find them at parts stores as "Ported vacuum switches".

Thanks! My passenger side valve cover has a chrome edelbrock filter on it, no pcv valve. There is also a similar sized port at the bottom (probably not visible in the pic) that connects to the drivers side valve cover. can I just tee into that?

And For the TSV, if its not in use, then i just need to figure out how to bypass the vacuum lines?

Thanks for the help. I'm coming from the fuel injection/electronic ignition world, so vacuum lines are mostly new to me

 

[Bextreme04]

Thanks! My passenger side valve cover has a chrome edelbrock filter on it, no pcv valve. There is also a similar sized port at the bottom (probably not visible in the pic) that connects to the drivers side valve cover. can I just tee into that?

And For the TSV, if its not in use, then i just need to figure out how to bypass the vacuum lines?

Thanks for the help. I'm coming from the fuel injection/electronic ignition world, so vacuum lines are mostly new to me

Ahhh, now I see it. That is the correct PCV setup then. The PCV valve is what that hose is connected to on your drivers side valve cover.

The TSV is currently bypassed and not connected to anything. Do you still have the emissions sticker that shows vacuum hose routing on your core support? That would tell you exactly where everything goes on your specific engine. I'm linking to a post where people have put pics their emissions stickers. Post #77 on the page I'm linking looks very close to yours. Its an 84 454 squarebody.

https://www.gmsquarebody.com/thread...m-and-tuning-stickers.3520/page-6#post-697300

Best guess from looking at your pics... all three of the not connected lines would go to the charcoal canister normally. If you dont have a charcoal canister and don't plan on putting one back in, you need to cap all of those off or it will have a MASSIVE vacuum leak and never run right.