83 C10 Vacuum System [HELP]

[Bo69]

I inherited this truck with the vaccum hoses all over the place, some off, some seemed to have disappeared, maybe some stuff has been deleted? I did my best to try to figure out where the remaining hoses went and capped off the rest of the ports. How did I do? Can some of this stuff just be deleted/plugged? The reason I started looking at the vacuum system is the truck idles really high while in park/neutral. I thought maybe due to a vacuum leak, but haven’t tested anything with a gauge yet as I didn’t have one laying around already. Maybe the carb is just extremely dirty, idk. I’m not a mechanic just a DIYer. Any help would be greatly appreciated!
Note: The original air filter was replaced by an aftermarket edelbrock open air system.
The idle is still running high when in park/drive, sometimes if you give it some gas it will come down on the idle some but still seems a bit high. I have also not cleaned the carb yet nor tried adjusting anything to die with the carb.
I’m not sure if this is the stock carburetor.

 

[fast 99]

Just can't start deleting things. Only way to do that is get rid of everything including intake, carb, dist, air pump, EGR all of it. Idle speed sounds like fast idle cam is sticking or choke thermostat is adjusted wrong or bad. Appears most of the original system is intact. Take it one item at a time. Trace through the circuit, repair as necessary. Chances are either 1 or both advances are defective, EGR is stuck or plugged. Carb may be bad, need to diagnose before condemning it. Look at one item at a time and move on.

 

[Bo69]

Just can't start deleting things. Only way to do that is get rid of everything including intake, carb, dist, air pump, EGR all of it. Idle speed sounds like fast idle cam is sticking or choke thermostat is adjusted wrong or bad. Appears most of the original system is intact. Take it one item at a time. Trace through the circuit, repair as necessary. Chances are either 1 or both advances are defective, EGR is stuck or plugged. Carb may be bad, need to diagnose before condemning it. Look at one item at a time and move on.

Thanks for the info, I’m not finding a decel valve as the system never had a T after the pcv valve it just went straight to the carb.. I was also having trouble finding the tvs stuff, decel valve, trans conv, continuing following the hose diagram; I also don’t see a distributor delay, efe, lastly I do not see a egr bleed sol, the egr on my truck never went to a T so I don’t have one nor do I see the other stuff that it’d run to anyways… I did try to google pictures of what these valves look like and for distributor delay; I found this on my truck but it only has 1 port on it not a bunch like the dist. delay in the diagram shows. So do you think the previous owner may have deleted stuff that I’d have to add back? Or am I just not seeing it correctly as I don’t know exactly what to look for when it comes to all the valves.

 

[fast 99]

Are there any pick and pull yards in your area? I had the same issue with an 81. Some idiot installed a Carter and yanked parts off not knowing what they were doing. Over the period of a few months all the missing parts showed up at a yard.

Many items are the same on cars during that time frame. One thing I ran into was that large 4 port TVS on the stat housing interfered with air cleaner. Had to buy an AC off E bay.

EGR's are almost always application specific. If yours is bad try to find either an AC Delco, GM or Delphi. Aftermarket EGR's aren't worth the box they are in.

 

[Ricko1966]

Y

 

[Bo69]

Thank you both, I’ve got it nearly figured out now. The only thing I’m not finding on the diagram is this; what is this thing on the side of the carb? Is it a choke? What hose should route to it if any? Should I keep it plugged or just leave it unplugged with no hose on it?

 

[Bo69]

Are there any pick and pull yards in your area? I had the same issue with an 81. Some idiot installed a Carter and yanked parts off not knowing what they were doing. Over the period of a few months all the missing parts showed up at a yard.

Many items are the same on cars during that time frame. One thing I ran into was that large 4 port TVS on the stat housing interfered with air cleaner. Had to buy an AC off E bay.

EGR's are almost always application specific. If yours is bad try to find either an AC Delco, GM or Delphi. Aftermarket EGR's aren't worth the box they are in.

Your egr valve is there, so are both tvs. I cannot tell if efe is there, or what distributor is in it. I would use the tvs and a ported vacuum source to make the egr operable. I would find out what distributor is in it and then ignition can be dealt with properly. Id make sure my transmission vacuum was setup correct. From there things should be pretty good. Maybe not perfect but acceptable.

please Read above, secondly I was wrong about all of the Valves being missing and found which ones were actually right in front of my face like both of the tvs however I am missing the decal valve, distributor delay valve, egr bleed sol, efe, so for those I just ran it as if it didn’t have one rather than capping anything off for example the distributor hose I ran straight to the carb port where the t goes and ignored the rest since I don’t have the decel valve anymore, is this ok or do I need to buy these few last valves I’m missing and just make it all like the factory did?

 

[Ricko1966]

X

 

[Bo69]

You need to find out what distributor you have. I'll try to get you some pics tomorrow, better would be distributor, but may be beyond your capabilities. Are you sure the egr bleed solenoidbus missing? The part you picture calling a distributor delay,is a vacuum advance unit and single hose is all I've ever seen on SBC. The delay valve is more the size of a 1/4 drive socket and could have to,or more vacuum hoses. We need to find out more about your distributor,I'll try to get you some pics of some stuff tomorrow.I think more is there than you realize just you don't know what you are looking for.

Yes I’m 100% missing the distributor delay, at the time I posted the picture I wasn’t sure what the delay looked like but now I do. It’s one of those little ones like you said with 4 ports but when I google I only see ones with 2 ports for some reason. I watched a video that explained almost everything to me the only part in the video that didn’t get explained is what this is? Is it the choke? Where is this in the vacuum diagram? I’m not seeing it on there, should I take the plug off of it or add a hose to it? If I add a hose where would it route to?

 

[Johnny Atomic]

Yes I’m 100% missing the distributor delay, at the time I posted the picture I wasn’t sure what the delay looked like but now I do. It’s one of those little ones like you said with 4 ports but when I google I only see ones with 2 ports for some reason. I watched a video that explained almost everything to me the only part in the video that didn’t get explained is what this is? Is it the choke? Where is this in the vacuum diagram? I’m not seeing it on there, should I take the plug off of it or add a hose to it? If I add a hose where would it route to?

My understanding is that is the choke pull-off. It is hooked to the choke linkage and also has to do with allowing the rear barrels to open.

 

[Johnny Atomic]

I have my own questions about this system, Mine is an 83 as well and has the same Emission Hose routing except mines does not have the green stripe hose going from air filter to canister.

Here is my diagram.


I'm trying to see what is what.
Here's a markup of the actual carb and , I numbered them Left to Right. Am I looking at these correctly???? PCV goes to the big port below the fuel filter correct????

 

[Bo69]

I have my own questions about this system, Mine is an 83 as well and has the same Emission Hose routing except mines does not have the green stripe hose going from air filter to canister.

Here is my diagram.


I'm trying to see what is what.
Here's a markup of the actual carb and , I numbered them Left to Right. Am I looking at these correctly???? PCV goes to the big port below the fuel filter correct????

Yes sir that would be correct according to the diagram

 

[Bo69]

My understanding is that is the choke pull-off. It is hooked to the choke linkage and also has to do with allowing the rear barrels to open.

Thank you for the reply, I think I’m going to ls swap it eventually anyways because this motor has no power and I have no desire to keep it all original. Sure I could rebuild and beef it up but I still think ls swap is the cheapest easiest bet for what I’m going for..

 

[Ricko1966]

Now I have a comment for all the I'm just going to L.S. swap it people. This isnt just aimed at you. If you have a rough time trying to sort out a stone stock sbc. Imagine how your going to feel trying to adapt an engine into a vehicle it wasn't designed for,Integrating modern EFI and Engine management. I can't say that I think doing an ls swap is the right first swap for someone unless they are very mechanically inclined.

 

[Geoduck]

Bo69, what engine type were you thinking to swap out to?
The vacuum lines are complicated but not impossible to sort out. Most can be removed and blocked/plugged at the carburetor.
The Quadrajet is a fine carburetor easy to rebuild and can provide outstanding performance.
Your truck may be later than my 85 but much of the vacuum plumbing looks the same. I can help you sort through it if you wish. Keep in mind I am NOT an expert.