General wisdom regarding keeping or eliminating Reservoir / Evap. Tank

[7T1240]

If you own a 240Z and live in a state which does not require emissions testing for your car, have you chosen to keep the whole evap. tank / reservoir with attendant fuel lines intact, or to eliminate them? And why?

Regards,

Gary S.

[Virto]

Check this thread: http://www.classiczcars.com/forums/showthread.php?t=19034&highlight=removing+evap

Good chance it'll answer a lot of questions you might have, as well as provide good detail on the process involved.

[TomoHawk]

The expansion tank is there in case the fuel tank overflows due to expansion of the gasoline, which isn't an emissions gadget. It's a matter of taste. Some will say just don't overfill the gas tank, others will say it doesn't expand that much.

[ncz]

Ditto, Dogma240 just posted an article on removal of the evap tank. Very nice piece. I'd go that route

[montoya_fan01]

The expansion tank is there in case the fuel tank overflows due to expansion of the gasoline, which isn't an emissions gadget. It's a matter of taste. Some will say just don't overfill the gas tank, others will say it doesn't expand that much.

I believe the above statement is inaccurate. It IS part of the emissions system.

Gasoline fumes (burned or unburned) ARE an emissions issue. That is why automobile fuel systems must be sealed and a car will fail a CA Smog Check examination due to something as minor as the gas cap not sealing properly.

As to keeping it or removing it, it's your call. You can get by without it, but if it is maintained in good order, it doesn't hurt anything.

[boostedz]

This is another simply put why question. It will do nothing to hinder the performance of your car if you leave it though it could hinder your car if you remove it.

I cant see why people always think well that is an emmisions device it robs power, it couldnt be farther from the truth.

Leave it and dont worry about it, it isnt hurting anything unless it isnt in good order.

[TomoHawk]

I will agree with Boostedz.

The evaporation tank isn't an emmissions device like a smog pump or EGR, but it does prevent spillage of fuel and it's supposed to collect and condense evaporated fuel and return it to the gas tank, and both aren't related to the engine's performance. Just a way to prevent gas from getting into the air.

Try to keep it in good working order or possibly replace it with one of the accepted devices.

[7T1240]

Just for clarification, my initial reason for broaching this subject is that I am having problems with exhaust and/or fuel fumes in the cabin, and also a fuel leak when the tank is full. I formed the question as I did because it is my understanding that this system is subject to scrutiny in states where emissions testing is still required. I solicited responses from folks who live in states where their cars are inspection exempt because the question of keeping or eliminating the system didn't seem pertinent to those in states where the system is still required to be in place. I'm not sure where the assumption was made that it might be my hope to gain horsepower by eliminating this system. I'm just trying to eliminate the various causes of fumes in the cabin. I realize that hatch seals, taillight seals, door seals, existence or absence of a rear spoiler, etc., etc. are all possible contributing factors to be explored, but the fuel tank and reservoir is the system I'm troubleshooting currently.

Tomohawk: Try to keep it in good working order or possibly replace it with one of the accepted devices.

Tom, what are the accepted devices you are referring to here?

[montoya_fan01]

The main causes of gasoline fumes in the cabin are rotten vent hoses, a broken plastic fitting between the fuel filler and the vent hoses, and lastly the slight possibility of a leaking evap tank.

I think the assumption regarding the reason for considering removal of the system was more directed at other people who foolishly leap at any excuse to remove systems that they think will result in some magical gain.

Exhaust fumes in the cabin are a different kettle of fish.

[TomoHawk]

Have you confirmed the presence of any fuel leaks? You mentioned fuel leaking. First fix that. You might want to replace any or all the gas tank hoses at the same time for peace of mind, but that's your decision. It sounds like you have a simple problem with fuel leakage. See if that's the problem, and if not, we can discuss further action.

The other thing about emmissions equipment is that people immediately associate it with engine performance, and this discussion went on a tangent.

There was a part you could buy that could replace the entire evaporation tank. Some kind of filtered vent, if I remember correctly, and it was supplied by a company that is no longer around (Midwest Z?) Somebody has a picture, I'll bet.

[7T1240]

Have you confirmed the presence of any fuel leaks? You mentioned fuel leaking.

Yes. To retrieve the car at purchase I had to bus about 170 miles from home. Before leaving the seller's town, I filled up the tank, then stopped to grab a cup of coffee before hitting the interstate. That's when I noticed fuel leaking under the car - at the gas tank, on the filler neck side. At the time, I did not attempt to pinpoint the source of the leak. And after that time, I (perhaps foolishly) did not attempt to recreate the problem by topping off the tank again. At this point, I will probably take the fuel tank to a shop to have it boiled out and pressure tested (if this is how they check for leaks). As you suggested, I will also probably replace most or all of the hoses and grommets, including the fuel filler hose.

There was a part you could buy that could replace the entire evaporation tank. Some kind of filtered vent, if I remember correctly, and it was supplied by a company that is no longer around (Midwest Z?) Somebody has a picture, I'll bet.

Interesting. Thanks for filling me in. I was just curious what you were referring to. Probably not the fix for me, especially given the questionable availability.

Gary S.

[beandip]

Just jack up the rear and put the car on a good set of stands. crawl under and look for the stains of fuel that has leaked and follow where it is or was coming from . If you are not having any trouble with rust in the fuel or the tank is not leaking at the seams or from damage from hitting something . There is no reason to take the tank to any shop . Most likely your problem is from a leaking vent line or the main fill hose . If you remove the right rear wheel , to the rear of the wheel well there is a small pannel that is held on with three sheet metal screws . Remove the pannel and you will be looking at the bottom end of the main filler hose . This large hose gets brittle and can crack . If you remove the fuel tank . Take care not to stress this large hose as it is costly to replace . If you do replace any of the vent hoses , DO NOT USE HEATER HOSE OR VACUUM HOSE for this . Only gasoline rated hose will due . The two large vent hoses are 5/8'' and available at Nappa or Nissan and where the have boat supplies. Nappa I found is the best place other than Nissan. Gary