What is this canister, and do I need it?

[balooshinakus]

I noticed this while taking apart my engine bay. There has never been a hose attached to the circled nipple on that canister. I also noticed a tube that appears to come from the rear of the car with nothing attached. This is how it has been for about a year since I bought the car. What the hell is this thing, do I need it?

[Danny]

Thats the Charcoal canister.

And no.

[balooshinakus]

Awesome, fast reply FTW :-)

[jahnaboi]

Its called and Evap canister. It condenses the vapors from your gas tank from sitting in the sun and allows it be sucked in by your intake manifold to be burnt up.

[scott_is]

You don't need it. I just plugged the vapor tube directly to the valve that
goes to the throttle body...been that way for 8 month now...works like a charm.

But I think that legally(smog) you need it.

Scott

[M3 euro ltw]

Need is a relative term

Depending on many factors, your gas tank may or may not seal well.

On very hot days or with hot gas, there can be postive pressure, and its helpful to have that tube "vent"ing.

I suspect that it is possible as well to creat vacuum in the tank, and that openening would allow air in, so you can continue to pump gas out. I would "vent" the line to the tank in some fashion to be on the safe side.

Obviously from an emissions standpoint, the EPA doesn't want your gas tank open to the environment.

I'm sure a certified mechanic can describe it better, but you get the drift.

(incidentally, now that you know that line goes back to your tank, I bet you're less than thrilled to know it can suck in a bunch of dirt and dust and stuff to foul pumps and injectors!)

[MR 325]

There is really no reason NOT to hook it up though.

[balooshinakus]

Guess I need to get new lines. I'm assuming the nipple with nothing connected needs to be hooked up to the line ipointed out with nothing connected?