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Old March 9th 18, 07:35 PM posted to rec.autos.tech
Steve W.[_6_]
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Posts: 1,161
Default Do we really need to use "dri gas" anymore?

dsi1 wrote:
> On Thursday, March 8, 2018 at 10:42:30 PM UTC-10, Steve W. wrote:
>> Show me a car that has a sealed system that actually runs. They are
>> all vented through the charcoal canister. Water vapor can still get
>> in as well as the amount that is already absorbed into the ethanol
>> in the gas.
>>
>> Dri-Gas can be helpful if you are using gas that has been stored a
>> while or that came from a store with low fuel sales. Or if you run
>> straight gas without ethanol like I do in all the small engines and
>> vehicles when possible.
>>
>> -- Steve W.

>
> There are valves in the fuel system to equalize tank pressure and the
> purge vapors from the charcoal canister. It's still a sealed system.
>



No it is not. You have a purge valve at one end that allows the engine
to pull the fuel vapor that is stored in the charcoal canister. At the
other end you have the canister VENT valve. The only time it closes is
when the system runs an EVAP test. The remainder of the time it is open
to allow the fuel tank to vent. The charcoal canister is in between the
tank and the vent valve. It's job is to capture the fuel vapor and keep
it from escaping out the vent into the atmosphere.



--
Steve W.
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