I know from the factory, the gas tank has a vent line with a valve on it that opened when the pressure reached a certain level, and the fumes were sent into the motor to be burned. Would there be any drawbacks to fully venting the talk 24/7 and just eliminating the valve/charcoal canister all together. I know of the possible pollution effects, but will venting the talk cause any problems? BTW, car is a 92 RS with a 305 tbi.

 

i believe it'll have an effect on preformance or operation if it's vented, but i don't know where i saw that or why it will.

 

That pollution you are talking about should be a hint. It is created by the release of unburned hydrocarbons to the atmosphere. As temperature increases, the vapor pressure of the fuel increases. If the tank is allowed to pressurize, the volatile hydrocarbons are kept in the tank (and fuel). These hydrocarbons are those that evaporate most easily (most volatile). They are also those that ignite most easily and violently. Losing those to the atmosphere would diminish the power producing ability of the fuel. If you burn a tank of gas in just a few days, it's probably not a problem. If you have fuel in your tank for a week or more, unless the tank is kept at a pressure that is above the vapor pressure of the fuel, it will begin to go "stale" after 5-7 days. You'll have your own little refinery process happening, but with no condensation phase to collect the best molecules. And you may collect more atmospheric moisture in the tank as a result.

When is the last time you heard of anyone having a fuel line freeze-up? It rarely happens any more, largely due to the lower moisture in the tank from better ventillation control.

 

Are these the symptoms older cars with vented gas caps suffered from?

 

Since the advent of "sealed" tanks and EVAP canisters in the early and mid '70s, losing fuel volatility and fuel line freezing aren't as common as they used to be.

 

So back in the late 60's and earlier, when most cars came with vented gas caps they had problems as serious as you make them out to be? I just find it hard to believe that by doing something cars had for decades it would really be so bad. But hey, I wasn't around back then, so feel free to correct me.

 

There's no need to "correct" you, since you're not "wrong". I'm not arguing. I'm just explaining some of the things that can happen if you eliminate the EVAP and vent your tank. If you eliminate the EVAP, you can replace it with a tank pressure control valve and probably get by without venting the cap. Even "non-vented" caps have a pressure relief and suction valve to prevent fuel tank damage/collapse.

I was around back then, and, yes, cars had more problems like stale fuel, fuel line freezing in winter, water in the fuel, etc. It didn't always happen to all cars, but it was a lot more common. It used to be very common for EVERYONE filling their tanks in sub-zero weather to pour in a can or two of DeMert's HEET or something similar to prevent problems.

Cars also used to run without a PCV system, too. They also ate more rings, seals, bearings, valves, oil, and dirtied the oil faster. Not everything that is "new" is bad.

If you don't live in a coastal region or a high humidity/low temperature area, you shouldn't have that kind of problem. Your fuel will tend to go stale faster, but as I mentioned earlier, if you burn a tank within a few weeks, you'll probably never notice a problem. In reality, fuel loses some volatility every time it is exposed to air. That's waht makes it explosive.

 

Thanks Vader, I appreciate the info. Thanks for explaining it a little further to me. Trust me, I know not everything new is bad. The only reason I am asking is because I am simply trying to "unclutter" my engine compartment. I don't want to run anything I don't really need, but at the same time I want to find out what I really do need, lol. Know what I mean?