vacuum line question

[Jtilden]

good day all,
Could someone please tell me where the vacuum line on the side of the oil filler goes? (1980 SC) Not the big one but the smaller 1/2 inch diameter. I am thinking it goes to the black canister right behind it but i want to make sure. thanks in advance for your replies.

[Jtilden]

the line is actually comes up to the left of the oil filter...it has been this way since I bought it, i put my finger over it and felt suction...i think i need to fix it, it might fix my surging idle problems

[Bob Kontak]

One end of the hose fits on the big port on the charcoal canister (behind the fuel pump on the inner fender. The connection is on the front of the car side of the canister. It travels to the driver's side of the air box where it is ported in BEFORE the air sensor. If you pull the air cleaner out you can see the port hole in the bottom left corner.

If I am correct, the big hose carries suction from intake vacuum and pulls vapors through the small diameter hose that is connected to the expansion tank in the driver's inner fender - the other end of the little hose is connected to the small diameter port on the same side of the canister the big port connects to.

On later CIS cars, the open port on the car's rear bumper side is left open.

The open system should have nothing to do with your surging idle. The vacuum comes from the same place the vacuum at the air cleaner cover snoot comes from.

[Bob Kontak]

Here is the "suction" port

[Bob Kontak]

My car's (81) hoses fell apart last time I pulled the engine. I don't understand the operation of the charcoal canister. It is not a sealed unit. If I plug two of the ports and blow with my mouth into a third it leaks air from around the bigger end of the canister. The function I understand - I think - just not how it works.