Trying to determine if the emissions line (emissions control pipe – third line from the tank) that used to go to the Emissions Canister needs to be plugged or should remain vented to the atmosphere. And, would this have an effect on whether the fuel cap should be vented, or not?
The way I look at it, the more venting the better. I have a vented cap on my 70 even though it calls for a non vented cap. I would copy the venting on the 70 cars and point the hose up at the tank and put one of those plastic pieces they use on the 70 cars. https://www.inlinetube.com/products...nHkicE4PiCgruNaodADz3hviRgVAXRvhoCB9QQAvD_BwE
I used a late 80's canister on mine. I just ran the hose into the bottom of the air cleaner assembly, between my throttle bodies. I have a sealed cap from the same era and have had no issues in 8k miles. An advantage to using a vapor canister is that I have no fuel smell in my garage as a lot of older cars do. I have no other venting on my tank.
Gotcha - thank you both for the replies. The original underhood line was tucked away behind the fenderwell. Trying to de-clutter and clean up the engine compartment, and came across the line. @1973gs - do you have a photo of the 80's canister you used?
I'm 99% sure that this is from a 1989 S-10 2.5l, # 17113148 but looking on RockAuto, it shows a different image. Actually, RA seems to show the same canister picture in many applications. At any rate, you'll need one that has 2 3/8 or 5/16 nipples, not one with a vacuum port as shown on RA. The part # on mine is 17075849, but numbers cast or molded on GM parts aren't always the actual part number.