Zlovemachine Posted April 17, 2008 Share Posted April 17, 2008 Hello Z Fans, I am interested in finding out the full function and fuel vapor box located in the hatch on the rear passenger side. Aside from the vapor box can I plug all the hole on the Fuel tank? Do I need it? What does it do? Why is it important to keep it? Can my car function without it? What kind of problems will I run into if I remove it? Sorry if some of the questions are redundant. Quote Link to comment Share on other sites More sharing options...
terrycoxusa Posted April 17, 2008 Share Posted April 17, 2008 The metal can in the passenger side hatch area is a fuel-air separator. One line drains back into the gas tank, one is a vent line from the filler, and one goes up to the charcoal can in the engine compartment. If you plug all the lines, your gas tank will build pressure when it warms up, because the vent in the filler cap is one-way, only breathes in. You could drill some small holes in the filler cap if you want to get rid of the separator tank, but it would probably slosh out gas. I left my whole system in place except for the charcoal cannister and I let the system vent through that hose (in the engine comp.) You could put a spiffy little filter on that line. Quote Link to comment Share on other sites More sharing options...
Zlovemachine Posted April 17, 2008 Author Share Posted April 17, 2008 So it sounds like i do not NEED it. Now that i remember I once had a Z with a fuel cell and i do recall there being a nipple at the very top of the tank. I could use it as a vent hose! Which would be the best located to use as a vent hose? I have a 71 240z tank. I am asking because i will be adding a sump to it since i am running EFI system. Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 27, 2008 Share Posted April 27, 2008 Aside from the vapor box can I plug all the hole on the Fuel tank? I'm not sure if you considered this, since it's not clear from your posts, but if you plug all the holes in the fuel tank, you will not be able to fill the tank! When you put fuel in the tank, the air that's in there has to be able to come out somewhere. Once you get past the level of the filler hose on the tank, that's it, no more fuel can go in. You need some means to let the tank breath. Also, there is no charcoal canister on a 240Z. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
MatMan Posted April 27, 2008 Share Posted April 27, 2008 You do not "need" the vapor can. I have eliminated it from my 71, and built a "manifold" with all the vent lines running through it, with a main line connected to the filler tube. All's well. Anyone looking for a plastic vapor tank? Quote Link to comment Share on other sites More sharing options...
evildky Posted April 27, 2008 Share Posted April 27, 2008 lots of us have removed them, I welded most of the tank ports shut but left one on each enr of the tank and routed them back to the filler neck so a fill up is not a problem Quote Link to comment Share on other sites More sharing options...
jerryb Posted April 27, 2008 Share Posted April 27, 2008 You should keep a vent hose on your tank and its best NOT to run it to atmosphere. The box will collect excess vapors condense them and drain back to the tank. Some of course will escape as one of the lines off the vapor box goes outside. Allow the tank breath......imagine if it was a sealed box and you pumped out all the fuel...or conversly....what happens to that plastic gas can when you leave it out in the sun. The vapor box is a light weight and simple component of your car that allow this to happen.......While reducing atmoshperic emissions. Quote Link to comment Share on other sites More sharing options...
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