I was muddling around in the trunk of my car the other day when it was 67F outside (yeah, you read that right- 67 in the first few days of January). I found that the clearish Vent tube (that then branches to three tubes) was "kinked" so Ithought, I should probably unkink it. well, that hard plastic wouldn't take a straightening out, so I chopped off about 4 inches of it and threw away the bad portion, and reattached it.
When I cut the line there was a big release of pressure considering the car had been sitting for a week or so without running. For the sake of learning, what problems could I have been experiencing from that, specifically would it impact the usage of fuel? I've been running awful rich (no, i still haven't replaced the T-stat, but I do have one now, lol) but that wouldn't seem to make sense to me aside from big pressure in tank would try to force a lot of fuel through the system (doesn't that seem unlikely?)
it's fixed now, so I guess it doesn't really matter.....but for S&Gs what do y'all think?
Gas Tank Venting
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racydave
Re: Gas Tank Venting
Hi Danno, one problem would be after a time, the tank would become under a vaccum, and would at a point, starve the carb for fuel. You would find out on a long trip! Ive heard that some people will drill a small hole in the gas cap to allow some air in. Lookin foreward to meetin up this year Dave
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mbouse
Re: Gas Tank Venting
sucking air in, or blowing air out?
when you changed over your carburetor and intake manifold....
did you happen to accidently do one of the following:
1) connect the former fuel return line from the old carb directly to a vacuum source?
2) abandon the charcoal canister and plug the vent tube that originally fed into the bottom of the black plastic canister?
when you changed over your carburetor and intake manifold....
did you happen to accidently do one of the following:
1) connect the former fuel return line from the old carb directly to a vacuum source?
2) abandon the charcoal canister and plug the vent tube that originally fed into the bottom of the black plastic canister?
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Danno
Re: Gas Tank Venting
Yes.mbouse wrote:sucking air in, or blowing air out?
Seriously, though, i dunno. Just made a "pfffft" noise and then it was done. never got a chance to put my finger up to it or anything. If I had to guess, I'd say it sucked air in, because in retrospect I don't think I smelled any fuel when it happened.
None of the above, I was very careful about all the things because when I couldn't get it to run initially I double and triple checked EVERYTHING, because my carb knowledge was so minimal I didn't know what was a minor thing and what was a major thing regarding all lines and connections (vacuums included). Does that make sense?mbouse wrote:when you changed over your carburetor and intake manifold....
did you happen to accidently do one of the following:
1) connect the former fuel return line from the old carb directly to a vacuum source?
2) abandon the charcoal canister and plug the vent tube that originally fed into the bottom of the black plastic canister?
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mbouse
Re: Gas Tank Venting
well, in this weather i think it is safe to rule out expanding fuel & fumes due to heating the tank...and lack of smelling fumes also indicates that the tank did not expel air when you cut the hose. think it is safe to say that you are getting a small vacuum. does it gulp air when you refuel?
you may have a plugged vent line to the charcoal canister from the tank. have you replaced all of the 9 foot of rubber hose between the tank and the steel fuel lines? is it possible that one or more have collapsed?
as Dave suggested, a 3/32" hole drilled in the center of the fuel cap may give you enough equalibrium to the tank.
you may have a plugged vent line to the charcoal canister from the tank. have you replaced all of the 9 foot of rubber hose between the tank and the steel fuel lines? is it possible that one or more have collapsed?
as Dave suggested, a 3/32" hole drilled in the center of the fuel cap may give you enough equalibrium to the tank.