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EFE TVS delete? I’m confused

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Old Mar 3, 2020 | 05:29 PM
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EFE TVS delete? I’m confused

Ive got headers for my bird so the heat riser valve is of no use. Can somebody help me understand which valves and such I can get rid of? Thanks!!
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Old Mar 3, 2020 | 05:30 PM
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Re: EFE TVS delete? I’m confused

Can I completely get rid of that vacuum sensor thing ( I snapped the fitting anyway) where the finger is kinda pointing. Also the heat riser valve never was functional when I owned it somebody deleted it because they replaced the sensor with one that has only one vacuum line attachment (which I broke)
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Old Mar 3, 2020 | 05:33 PM
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Re: EFE TVS delete? I’m confused

Which lines on the carb can I then cap off?
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Old Mar 5, 2020 | 03:27 PM
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Re: EFE TVS delete? I’m confused

Pretty sure you need the large valve you have circled for the fuel vapor canister purge system.

The one you have circled on the water neck is a "ported vacuum switch". If you broke that one they are only a few dollars on rock auto. As for deleting it I'm not familiar enough with the system to help there
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Old Mar 5, 2020 | 03:29 PM
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Re: EFE TVS delete? I’m confused

If you do end up deleting the ported vac switch all you need is a pipe plug, they sell little bags of them on Amazon with multiple sizes, many different materials and finishes are available.
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Old Mar 5, 2020 | 05:21 PM
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Re: EFE TVS delete? I’m confused

Is your ECM still controlling the carb and distributor? It does not seem so from the pictures.
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Old Mar 7, 2020 | 10:45 PM
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Re: EFE TVS delete? I’m confused

Originally Posted by NoEmissions84TA
Is your ECM still controlling the carb and distributor? It does not seem so from the pictures.
yes it is, the engine is partially disassembled as I was in the process of pulling it when the pic was taken
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Old Mar 7, 2020 | 10:48 PM
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Re: EFE TVS delete? I’m confused

Originally Posted by Handy_man91
Pretty sure you need the large valve you have circled for the fuel vapor canister purge system.

The one you have circled on the water neck is a "ported vacuum switch". If you broke that one they are only a few dollars on rock auto. As for deleting it I'm not familiar enough with the system to help there
gotcha I didn’t think that looked right, I want to keep that for sure... as for the ported vacuum switch from what I can tell the stock one had 2 fittings one for the exhaust flapper valve thing, and one for something else. My car had the exhaust flapper disabled and the fitting was replaced with a single outlet one. Do you know what that outlet is for?
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Old Mar 7, 2020 | 10:48 PM
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Re: EFE TVS delete? I’m confused

Originally Posted by Handy_man91
If you do end up deleting the ported vac switch all you need is a pipe plug, they sell little bags of them on Amazon with multiple sizes, many different materials and finishes are available.
thank you I am not sure if I should remove it or not because I’m not sure what that vacuum line does
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Old Mar 7, 2020 | 10:57 PM
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Re: EFE TVS delete? I’m confused

What does the underhood vacuum diagram sticker show, if it's still there?
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Old Mar 8, 2020 | 12:20 AM
  #11  
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Re: EFE TVS delete? I’m confused

The TVS in the thermostat housing you have circled can be removed and the fitting plugged.
You should keep the cannister control valve (the big thing circled)...
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Old Mar 8, 2020 | 12:28 AM
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Re: EFE TVS delete? I’m confused

Originally Posted by 82Firebird5.0
Which lines on the carb can I then cap off?
Whatever ports are not being used...
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Old Mar 8, 2020 | 09:47 AM
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Re: EFE TVS delete? I’m confused

The Thermal Vacuum Switch in the water neck provided vacuum to the Early Fuel Evaporation (EFE) valve in the passenger side exhaust manifold. When cold it would close this valve to re-route exhaust through the cross over passages in the intake manifold. This warmed the manifold, warming the fuel/air mixture, hence Early Fuel Evaporation.

If the valve is gone you can, as said above, remove the valve and plug the opening. Plug the port on the carb that the vacuum source was removed from and remove any of the vacuum lines left, including the steel piece that ran along the perimeter of the valve cover.
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Old Mar 26, 2020 | 08:43 AM
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Re: EFE TVS delete? I’m confused

Originally Posted by T.L.
Whatever ports are not being used...
Originally Posted by naf
The Thermal Vacuum Switch in the water neck provided vacuum to the Early Fuel Evaporation (EFE) valve in the passenger side exhaust manifold. When cold it would close this valve to re-route exhaust through the cross over passages in the intake manifold. This warmed the manifold, warming the fuel/air mixture, hence Early Fuel Evaporation.

If the valve is gone you can, as said above, remove the valve and plug the opening. Plug the port on the carb that the vacuum source was removed from and remove any of the vacuum lines left, including the steel piece that ran along the perimeter of the valve cover.
for some reason this never showed up in my inbox like the notifications usually do... anyway thanks for the reply I’m still a little confused as to what the remaining vacuum port does...
I’ve concluded the exhaust flap was deleted by the previous owner and that’s why the remaining switch only has one port. This remaining port— what does it do? I also am not sure what replacement part to buy there are many different temperature switches... can anybody tell me what the remaining port does?
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Old Mar 26, 2020 | 08:43 AM
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Re: EFE TVS delete? I’m confused

Originally Posted by NoEmissions84TA
What does the underhood vacuum diagram sticker show, if it's still there?
I didn’t notice it still being there but I’ll look again when I get the chance
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Old Mar 26, 2020 | 11:54 AM
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Re: EFE TVS delete? I’m confused

what do you mean by 'remaining port'

if there is only one open nipple on the vacuum switch, then one broke off.

all the switch does is close a valve between the two ports at some specified temperature. this allows vacuum to pass between the two ports. in this case everything past the switch would be under vacuum from the source (manifold engine vacuum with engine running) until the water temp warms the switch and it closes.

if you remove it you can plug the opening in the water neck with a suitable plug and cap off the vacuum port on the carb that originally provided vacuum-provided it is not already capped.
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Old Mar 26, 2020 | 01:46 PM
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Re: EFE TVS delete? I’m confused

Originally Posted by naf
what do you mean by 'remaining port'

if there is only one open nipple on the vacuum switch, then one broke off.

all the switch does is close a valve between the two ports at some specified temperature. this allows vacuum to pass between the two ports. in this case everything past the switch would be under vacuum from the source (manifold engine vacuum with engine running) until the water temp warms the switch and it closes.

if you remove it you can plug the opening in the water neck with a suitable plug and cap off the vacuum port on the carb that originally provided vacuum-provided it is not already capped.
I’m telling you it is shorter than a stock one somebody replaced the switch with a single port one lol it took me a while to fight re that out I was confused. So one port controls the flapper in the exhaust manifold but what does the other port do?
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Old Mar 27, 2020 | 07:15 AM
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Re: EFE TVS delete? I’m confused

it is a switch. one input port and one output port.
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Old Mar 27, 2020 | 11:02 AM
  #19  
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Re: EFE TVS delete? I’m confused

Originally Posted by naf
it is a switch. one input port and one output port.
ohh gotcha... so I don’t need it at all if I delete the air system? It doesn’t do anything with the egr or timing or anything?
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Old Mar 27, 2020 | 12:48 PM
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Re: EFE TVS delete? I’m confused

Yeah, you can remove it...

Last edited by T.L.; Mar 27, 2020 at 01:01 PM.
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