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CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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)
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
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.
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?
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
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)...
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.
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?
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.
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?
03-03-2020, 05:29 PM
