TVS Hoses for '78

[Mike M.]

Guys, I am brand new to this site. In fact, this is my first post. I have been reading through much of the C3 forum and what a GREAT resource! I have a lot of respect for many of you and your knowledge. My girl and I adopted a 'project car'. It a '78 with a 350 and I think the original carb. She knows more about cars than me so I'm trying to learn as much as possible as fast as possible to protect my manhood. So here's my issue - what hoses connect to the TVS? There are two connections (top and bottom). Thanks in advance!

 

[Ezmunie]

Welcome!

Welcome to the Mike. Like you said, there is plenty of knowledge here and most everyone willing to share it. I am not too familiar with the C3, but I am sure someone will chime in soon that can help you with your question. I would also suggest that you get a manual. They can be alot of help. Enoy your new ride!

 

[BarryK]

WHICH TVS?

on a '78 there are two of them. one is right on top of the t-stat housing and the other is close to that but screwed directly into the manifold.

The one on the top of the t-stat housing is called the EFE TVS:
EFE= Early Fuel Evaporation
TVS = Thermal Vacuum Switch

The one directly in the intake manifold is called the EGR TVS:
EGR = Exhaust Gas Re-Circulate
TVS = Thermal Vacuum Switch

The EFE TVS hoses go as follows:
Top connector position: On an L48 motor the hose goes from the top connector postion to a check valve than to a vacuum connection on the frontside of the carb. On an L82 motor it goes from the top connector to a check valve to a "tee" fitting. Off the "tee" fitting it goes from side side to a vacuum port on the frontside of the card and from the other side of the "tee" fitting it goes to the AIR Pump.
Bottom Connector: on either model motor the hose goes from the bottom conection directly to the Vaccum actualtor that is mounted off the passenger side exhaust manifold that controls the heat riser below that same exhaust manifold.

EGR TVS hose go as follows:
Top connector: hose goes from the top connector to the EGR valve on the passenger side of the intake manifold
Botton connector: hose goes from the bottom connector to a vacuum port on the front side of the carb.
(EGR TVS hose connections are the same on both the L48 and L82 motors)

hope this helps

 

[Mike M.]

Barry, well you've made my first posting a very positive experience. It is the EFE TVS I'm talking about, so you've nailed the response. I'll also check the EGR hoses since you've included that. The previous owner was determined to slowly kill this car, so we have a lotta work to get her healthy. Once we cleaned out the old wasps nests under the hood, we started noticing the 'pin the donkey' approach to his hose scheme. Thanks very much!