Vacuum lines and emissions components - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sgr60 · 11-18-2014, 09:36 PM

I've gotten around to poking around in my engine compartment in order to get an idea of what my next steps are going to be. One of the things that's new to me on this truck is all the emissions stuff and the huge amount of vacuum lines. I like to keep things clean and simple, so I am going to look to get rid of as much of this as I can. I realize emissions components aren't supposed to be removed - nevertheless, if it won't hurt the performance of the engine by being removed, I'd rather take it off.

I took a few photos and I'm hoping folks can help me to identify what some of these are:

Red Circle - I found these hoses cut when I bought the truck - no idea what they're for or why they were cut. Has anyone seen this done? Should the ends be capped?
Blue circle - this went into the stock air cleaner - which I no longer plan to use in favor of a simple chrome air filter. What should I do with this hose? Cap it? It leads to a T connecter - one end to the vapor can, the other I can't remember.
Yellow Circle - what is this MESS? All of these hoses are degraded and tangled up. There are two pieces of hardware in there that some of them connect to - are these the one is connected to the thermostat housing and the other is right next to it. Can I remove these and just cap the ends on the block, carb, etc. where they originate?

Sorry for the basic questions - this is all new to me.

K5owner · 11-18-2014, 11:41 PM

Do you have emissions testing in your state/area? If so leave the emissions stuff alone. Trust me if you need it and remove it thinking you are going to reinstall come time to smog you are going to be stuck.

sgr60 · 11-19-2014, 12:46 AM

Quote:

Originally Posted by K5owner

Do you have emissions testing in your state/area? If so leave the emissions stuff alone. Trust me if you need it and remove it thinking you are going to reinstall come time to smog you are going to be stuck.

Nope, no emissions testing in CT on vehicles over 25 years old. I know removing the smog stuff is still prohibited, but with no inspections, I'm not going to worry about it...

Anyone able to help with the info from the photos?

K5owner · 11-19-2014, 11:20 AM

I take it you don't have a chilton, haynes or GM repair manual or even a radiator support engine decal? This has all the emission related component locations, names and vacuum routing map. The decal should look like this:
http://repairguide.autozone.com/znet...528005c551.gif

What is circled in red on my vehicle is called the A.I.R. manifold valve. In yellow is the EFE TVS and the circular can in front of it is called the decel. valve. But my decal is a XFJ

Yes you can remove all of it (EGR valve, SMOG pump, all the associated hoses and lines and go bare bones. It really won't net you any meaningful power gains as these engines are rather anemic by todays standards. If it were me I would remove all of it and put a nice Weiand stealth intake manifold, rebuild the quadrajet with a ruggles kit, dial in the timing and distributor advance curves. If you are going that route you might as well ditch the cast iron manifolds and get a nice set of headers and dual exhaust. At least this way that 260 or 290 HP crate engine (assuming that is what it is by those valve cover decals) can run as good as it can. I would opt to swap out cams as well to something a bit better suited for a truck as well. Search cam swaps on crate engines for more info on that.

sgr60 · 11-19-2014, 09:08 PM

Quote:

Originally Posted by K5owner

I take it you don't have a chilton, haynes or GM repair manual or even a radiator support engine decal? This has all the emission related component locations, names and vacuum routing map. The decal should look like this:
http://repairguide.autozone.com/znet...528005c551.gif

What is circled in red on my vehicle is called the A.I.R. manifold valve. In yellow is the EFE TVS and the circular can in front of it is called the decel. valve. But my decal is a XFJ

Yes you can remove all of it (EGR valve, SMOG pump, all the associated hoses and lines and go bare bones. It really won't net you any meaningful power gains as these engines are rather anemic by todays standards. If it were me I would remove all of it and put a nice Weiand stealth intake manifold, rebuild the quadrajet with a ruggles kit, dial in the timing and distributor advance curves. If you are going that route you might as well ditch the cast iron manifolds and get a nice set of headers and dual exhaust. At least this way that 260 or 290 HP crate engine (assuming that is what it is by those valve cover decals) can run as good as it can. I would opt to swap out cams as well to something a bit better suited for a truck as well. Search cam swaps on crate engines for more info on that.

Awesome - exactly what I was looking for. I actually do have the Chilton manual, but I never noticed that it had that whole section on the emission stuff - thanks for that.

I definitely like the advice on the next steps - I was thinking very similarly.

sgr60 · 11-23-2014, 08:44 PM

I can't find any reference to the "decel" in my haynes manual (In front of the yellow circle in the photo above). Is there another name for it??

Thanks.

Just call me Sean · 11-23-2014, 08:51 PM

I think it's called the deceleration valve. It's for the smog pump controls. It keeps air from being pumped in upon deceleration so the truck doesn't backfire.

sgr60 · 11-23-2014, 08:56 PM

Thanks - found it.

sgr60 · 11-23-2014, 09:24 PM

For those of you that have removed the stock air intake/cleaner housing for in favor of a traditional air cleaner, what did you do with the opening on the valve cover where this tube came out of - just plug it or use a breather? (red circle, ignore the arrows)

K5owner · 11-23-2014, 09:30 PM

Plug it with the appropriate size rubber plug. Or change valve covers.

sgr60 · 11-23-2014, 09:49 PM

Awesome - thanks.

My next question - with the smog pump and deceleration valve removed - what's the best way to handle the vacuum lines that were going into the deceleration valve? As it is on my truck, one line went to the air cleaner housing (which I'm removing too so no worries there) and the other line comes out of the valve and into the bottom of a T. The left side goes to a vacuum port on the carb, and the right side to the vapor canister. So the question - should I remove the T valve and just put in a straight connector from the carb to the vapor canister? The seems like the most logical solution, just want to be sure.

sgr60 · 11-23-2014, 09:51 PM

Awesome - thanks.

My next question - with the smog pump and deceleration valve removed - what's the best way to handle the vacuum lines that were going into the deceleration valve? As it is on my truck, one line went to the air cleaner housing (which I'm removing too so no worries there) and the other line comes out of the valve and into the bottom of a T. The left side goes to a vacuum port on the carb, and the right side to the vapor canister. So the question - should I remove the T valve and just put in a straight connector from the carb to the vapor canister? The seems like the most logical solution, just want to be sure.

sgr60 · 11-24-2014, 04:48 PM

Any ideas on this?

Quote:

Originally Posted by sgr60

My next question - with the smog pump and deceleration valve removed - what's the best way to handle the vacuum lines that were going into the deceleration valve? As it is on my truck, one line went to the air cleaner housing (which I'm removing too so no worries there) and the other line comes out of the valve and into the bottom of a T. The left side goes to a vacuum port on the carb, and the right side to the vapor canister. So the question - should I remove the T valve and just put in a straight connector from the carb to the vapor canister? The seems like the most logical solution, just want to be sure.

Bigstevex4 · 11-23-2014, 10:03 PM

Most that stuff on my 83 with a 6 has been disconnected long before I got it started cleaning it up got a 5 gal bucket hoses lines charcoal can pulled a senior out stat housing must have 6 vacuum lines on it I stuck a breather in the cover were the tube and Egr were. Of course I wouldn't have don any if it were not off road use only

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83swb · 11-24-2014, 12:44 AM

Wow, that's quite the mess you have there. If I was in the situation you are currently in I would tear everything in that tangled mess of smog equipment and vacuum junk off and start from scratch, gives me a headache looking at it

. Sorry I can't be much help.

sgr60 · 11-24-2014, 12:50 AM

Quote:

Originally Posted by 83swb

Wow, that's quite the mess you have there. If I was in the situation you are currently in I would tear everything in that tangled mess of smog equipment and vacuum junk off and start from scratch, gives me a headache looking at it

. Sorry I can't be much help.

Just how I'm feeling! Little by little I'm getting it removed as I understand what each part is. IMO less is more.

ChevDog1 · 11-24-2014, 11:49 AM

Hey BigSteve - What carb are you running on your 6? Are you happy with it?

Bigstevex4 · 11-25-2014, 11:03 AM

Quote:

Originally Posted by ChevDog1

Hey BigSteve - What carb are you running on your 6? Are you happy with it?

Had it with Varijet bought an early 70s mono jet off ebay rebuilt it had to make my own adapter plate. and yes ime very happy with it this truck is geard high and have slightly over sized tires so no power house but starts and runs so much better had nothing but problems before.

Just call me Sean · 11-24-2014, 07:36 PM

Yours looks like my '86 was. Posting a pic of your vacuum diagram might help. I can't visualize it with you telling me but I can figure it out with the diagram.

sgr60 · 11-25-2014, 10:12 AM

Thanks - here's the diagram:

Just call me Sean · 11-25-2014, 08:32 PM

The one between the carb and PCV eliminate the tee, the one that went to the air cleaner should be capped at the canister, the pink one will be gone with all that other crap.

sgr60 · 11-25-2014, 10:09 PM

Quote:

Originally Posted by Just call me Sean

The one between the carb and PCV eliminate the tee, the one that went to the air cleaner should be capped at the canister, the pink one will be gone with all that other crap.

Excellent - thanks. I'm working on modifying the diagram to show what I left behind after my work today. Not much left from what was there - it's a lot neater, hopefully no issues.

sgr60 · 11-25-2014, 10:29 PM

Here is what my vacuum lines look like now - if anyone sees any issues that I might have please let me know. I do want to keep to vapor can so that the fuel tank can vent there. I also want to make sure that I have the vacuum advance for the distributor connected to a proper port on the carb - is the same as it was, but with all the stuff in the middle removed.

At the moment, it seems to run better than it did before...

sgr60 · 11-28-2014, 01:16 AM

Any thoughts on the above vacuum routing?

K5owner · 11-28-2014, 01:38 AM

EGR valve cannot be replaced with a breather. You must use plate to physically block off the mount on the manifold. Other then that yeah that looks good. I would just replace the intake manifold with an aftermarket of your choice and delete the EGR entirely.

11-18-2014, 09:36 PM	#1
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Vacuum lines and emissions components I've gotten around to poking around in my engine compartment in order to get an idea of what my next steps are going to be. One of the things that's new to me on this truck is all the emissions stuff and the huge amount of vacuum lines. I like to keep things clean and simple, so I am going to look to get rid of as much of this as I can. I realize emissions components aren't supposed to be removed - nevertheless, if it won't hurt the performance of the engine by being removed, I'd rather take it off. I took a few photos and I'm hoping folks can help me to identify what some of these are: Red Circle - I found these hoses cut when I bought the truck - no idea what they're for or why they were cut. Has anyone seen this done? Should the ends be capped? Blue circle - this went into the stock air cleaner - which I no longer plan to use in favor of a simple chrome air filter. What should I do with this hose? Cap it? It leads to a T connecter - one end to the vapor can, the other I can't remember. Yellow Circle - what is this MESS? All of these hoses are degraded and tangled up. There are two pieces of hardware in there that some of them connect to - are these the one is connected to the thermostat housing and the other is right next to it. Can I remove these and just cap the ends on the block, carb, etc. where they originate? Sorry for the basic questions - this is all new to me. __________________ '84 K20 350/465/208

11-18-2014, 11:41 PM	#2
K5owner Registered User Join Date: Mar 2014 Location: CA Posts: 168	Re: Vacuum lines and emissions components Do you have emissions testing in your state/area? If so leave the emissions stuff alone. Trust me if you need it and remove it thinking you are going to reinstall come time to smog you are going to be stuck.

11-19-2014, 11:20 AM	#4
K5owner Registered User Join Date: Mar 2014 Location: CA Posts: 168	Re: Vacuum lines and emissions components I take it you don't have a chilton, haynes or GM repair manual or even a radiator support engine decal? This has all the emission related component locations, names and vacuum routing map. The decal should look like this: http://repairguide.autozone.com/znet...528005c551.gif What is circled in red on my vehicle is called the A.I.R. manifold valve. In yellow is the EFE TVS and the circular can in front of it is called the decel. valve. But my decal is a XFJ Yes you can remove all of it (EGR valve, SMOG pump, all the associated hoses and lines and go bare bones. It really won't net you any meaningful power gains as these engines are rather anemic by todays standards. If it were me I would remove all of it and put a nice Weiand stealth intake manifold, rebuild the quadrajet with a ruggles kit, dial in the timing and distributor advance curves. If you are going that route you might as well ditch the cast iron manifolds and get a nice set of headers and dual exhaust. At least this way that 260 or 290 HP crate engine (assuming that is what it is by those valve cover decals) can run as good as it can. I would opt to swap out cams as well to something a bit better suited for a truck as well. Search cam swaps on crate engines for more info on that. Last edited by K5owner; 11-19-2014 at 11:48 AM.

11-23-2014, 08:44 PM	#6
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components I can't find any reference to the "decel" in my haynes manual (In front of the yellow circle in the photo above). Is there another name for it?? Thanks. __________________ '84 K20 350/465/208

11-23-2014, 08:56 PM	#8
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Thanks - found it. __________________ '84 K20 350/465/208

11-23-2014, 09:24 PM	#9
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components For those of you that have removed the stock air intake/cleaner housing for in favor of a traditional air cleaner, what did you do with the opening on the valve cover where this tube came out of - just plug it or use a breather? (red circle, ignore the arrows) __________________ '84 K20 350/465/208

11-23-2014, 09:30 PM	#10
K5owner Registered User Join Date: Mar 2014 Location: CA Posts: 168	Re: Vacuum lines and emissions components Plug it with the appropriate size rubber plug. Or change valve covers.

11-23-2014, 09:49 PM	#11
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Awesome - thanks. My next question - with the smog pump and deceleration valve removed - what's the best way to handle the vacuum lines that were going into the deceleration valve? As it is on my truck, one line went to the air cleaner housing (which I'm removing too so no worries there) and the other line comes out of the valve and into the bottom of a T. The left side goes to a vacuum port on the carb, and the right side to the vapor canister. So the question - should I remove the T valve and just put in a straight connector from the carb to the vapor canister? The seems like the most logical solution, just want to be sure. __________________ '84 K20 350/465/208

11-23-2014, 09:51 PM	#12
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Awesome - thanks. My next question - with the smog pump and deceleration valve removed - what's the best way to handle the vacuum lines that were going into the deceleration valve? As it is on my truck, one line went to the air cleaner housing (which I'm removing too so no worries there) and the other line comes out of the valve and into the bottom of a T. The left side goes to a vacuum port on the carb, and the right side to the vapor canister. So the question - should I remove the T valve and just put in a straight connector from the carb to the vapor canister? The seems like the most logical solution, just want to be sure. __________________ '84 K20 350/465/208

11-23-2014, 10:03 PM	#14
Bigstevex4 Registered User Join Date: Oct 2014 Location: Spearfish South Dakota Posts: 407	Re: Vacuum lines and emissions components Most that stuff on my 83 with a 6 has been disconnected long before I got it started cleaning it up got a 5 gal bucket hoses lines charcoal can pulled a senior out stat housing must have 6 vacuum lines on it I stuck a breather in the cover were the tube and Egr were. Of course I wouldn't have don any if it were not off road use only

11-24-2014, 12:44 AM	#15
83swb Registered User Join Date: Sep 2012 Location: CT Posts: 133	Re: Vacuum lines and emissions components Wow, that's quite the mess you have there. If I was in the situation you are currently in I would tear everything in that tangled mess of smog equipment and vacuum junk off and start from scratch, gives me a headache looking at it . Sorry I can't be much help.

11-24-2014, 11:49 AM	#17
ChevDog1 Registered User Join Date: Aug 2013 Location: Banks, OR Posts: 497	Re: Vacuum lines and emissions components Hey BigSteve - What carb are you running on your 6? Are you happy with it?

11-25-2014, 10:12 AM	#20
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Thanks - here's the diagram: __________________ '84 K20 350/465/208

11-25-2014, 10:29 PM	#23
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Here is what my vacuum lines look like now - if anyone sees any issues that I might have please let me know. I do want to keep to vapor can so that the fuel tank can vent there. I also want to make sure that I have the vacuum advance for the distributor connected to a proper port on the carb - is the same as it was, but with all the stuff in the middle removed. At the moment, it seems to run better than it did before... __________________ '84 K20 350/465/208

11-28-2014, 01:16 AM	#24
sgr60 Registered User Join Date: Nov 2014 Location: CT Posts: 105	Re: Vacuum lines and emissions components Any thoughts on the above vacuum routing? __________________ '84 K20 350/465/208



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11-28-2014, 01:38 AM	#25
K5owner Registered User Join Date: Mar 2014 Location: CA Posts: 168	Re: Vacuum lines and emissions components EGR valve cannot be replaced with a breather. You must use plate to physically block off the mount on the manifold. Other then that yeah that looks good. I would just replace the intake manifold with an aftermarket of your choice and delete the EGR entirely.

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