Where does this vcv hose go? (1 Viewer)

[Keep]

Trying to undo a badly done desmog job on a 78 2F. Where should this hose go from the vcv?

 

[mattressking]

There is a port off the Insulator under the carburetor it connects to.

 

[spotcruiser]

As noted above, it goes to a port below the carb. That looks like a 79 and later emissions diagram. Is your truck 9/78 and later?

 

[Keep]

No, its 4/78. I used that diagram more to illustrate the hose. I'm basing my connections on the 1978 emmisions manual, but I don't see where that hose goes in the manual. It had a poorly performing Weber when I got it. I put the correct model Aisin model on, but can't find that port. Perhaps it was removed for the Weber...?

 

[mattressking]

No, its 4/78. I used that diagram more to illustrate the hose. I'm basing my connections on the 1978 emmisions manual, but I don't see where that hose goes in the manual. It had a poorly performing Weber when I got it. I put the correct model Aisin model on, but can't find that port. Perhaps it was removed for the Weber...?

You will not find it on the Weber or Aisin, it is on the carb insulator (below) therefore you need to locate the correct insulator with the port.

 

[Keep]

Thanks for the pic, that helps!

 

[spotcruiser]

As mattressking noted. This is my 78. Red hose.

 

[Keep]

Found it, thanks for the help. It actually has a loop on it. Where is forward port supposed to go?

 

[spotcruiser]

My 78 is a CA truck. The emissions manual shows a similar routing for other versions. The hose from that forward port at the carb spacer runs up to the small rectangular box at the top front of the carb (I don't know the purpose of the box; damper of some sort, possibly) and then to a port on the front of the carb. I do not know the function of this portion of the circuit and it doesn't appear to be addressed by the manual. I'm sure @FJ40Jim can explain what it does.

It's the hose not highlighted in this diagram.

Found it, thanks for the help. It actually has a loop on it. Where is forward port supposed to go?

 

[FJ40Jim]

The square-ish box is the Hot Idle Compensator. The HIC is temp sensitive and opens up as underhood temps get high, allowing more air into the engine, raising the idle speed. Higher idle speed equates with more cooling fan, more water pump flow and cleaner running.
Connect as Spot has shown and drive happy.