Xenodrgn

Scrap that crappy vent canister... can i rip it out and hook the fuel tank ventline directly to a ported vacuum source?

I'm conserned with blowing myself up, or messing up some kinda vital pressure/vacuum balance GM has going on here...

It seems like a logical thing to do... What do you think?

Xenodrgn

c'mon.. I know this question isn't -that- stupid!

:lala:

ronterry

Yea, but wouldn't it only vent for about 2 seconds? and if you had a vented cap, or in the case of my '82 which has a little air filter deal down by the tank, you would lose source vacuum (vacuum leak).

I thought the canister stores engine(after shut off) & gas tank vapor so it can be reburned durning a cold start?

Ron

ede

most if not all thirdgen f bodys have a line hanging from the tank, an air intake i believe. you wouldn't want to suck the fumes into the engine, that's the last palce you'd want them. why would you want to change the design or function frm what gm made? there wouldn't be any preformance gains and actually it'd hurt by putting gas vapors in the engine.

99Hawk120

Hahahaha, it's funny you should ask because I did that by accident. I spliced the vacuum line going to the charcoal canister to the wrong side.

In addition to getting rich exhaust codes constantly, the gas tank emitted a sound like a dying cow when the motor was shut down as the tank sucked enough air back in to equalize to atmospheric pressure (or close to it).

Bottom line: bad idea.

Xenodrgn

rofl... dieing cow..

Ok, thanks guys. Now you know why I ask these kinda questions... You guys always think of stuff that I never do.

MOOO!!! :lala:

99Hawk120

You wouldn't believe how long it took me to track down the problem either!

MOOOOOOOOOOOOOOOOOO!

TomP

(choking, spluttering, coffee-out-the-nose laughter) DAMMIT! Oh damn I'm crying..

99Hawk120

I should hook it back up that way, and make a recording of it.

2vmodular

are two lines running into the charcoal canister. one is manifold vacuum. the other is a vent line for the gas tank.

the manifold vacuum line has a solenoid on it and only applies vacuum to the canister for a very short period after the car starts.

the vent line is a direct run to the tank. leaving it venting to the atmosphere will increase hydrocarbon emissions (smog) but will not affect engine operation.

make sure not to plug the vent line, it can cause the gas tank to collapse. sort of like when you take an plastic soda bottle and suck all the fluid and air out of it. but in this case instead of your lungs as the siphon, you've got a fuel pump.

99Hawk120

The older carbed cars, like mine, have no solenoid. It's purely vacuum controlled.

Homer

iTrader: (1)

What do these solenoids look like? I'm asking because on my car, one of the vacuum line comes off the canister, splits, goes into two round plastic things, and then one goes to the carb and one hose leads to nowhere (that can't be good). Then there's a hose coming off my aircleaner that connects to nothing (I was thinking maybe they go together, but the vacuum hoses aren't even the same size). Should I just connect these two points with vacuum hose? And assume if I hear no dying cow then it's ok?
Thanks,
Homer

99Hawk120

The carbureted cars don't utilize a solenoid. At least, mine doesn't.

Homer

iTrader: (1)

Ok, so do you know where the hoses go? I was going to replace all my vacuum line since it's all old and cracked, but if there's open hoses and I don't know where they go it seems like a pointless endeavor. Do you know where the hose from the air cleaner is supposed to go? I wish my shop manual had more picutures.
Thanks

99Hawk120

I have them all set up on my car properly. If I remember, I'll take some digital pictures of my hose setup for you tonight when I'm out working on my stupid rear.

RB83L69

ROTFLMAO!!

Actually, that valve died on my car, it sounded to me like something back there was blowing its nose for a couple of seconds every couple of minutes for about an hour after driving the car.... it took about a year before it finally got to me so bad I laid up under the car waiting for it to do it so I could strafe it with an Uzi. That had to be the weirdest noise I think it has ever made.

The carb cars actually have some kind of thermal vacuum switch that controls it. It's the big one in the intake next to the water outlet, right behind that really big fuky round thing that hanges off the front of the motor right above the water pump.