Mark, if you have the PC/ED manual, look at Evaporative Emission (EVAP) System section 1-101. You will find out about the enhanced system.

GaryG

 

The enhanced system means the pcm controls and tests the evap system. This system is not that new. It is possible to get liquid fuel into the canister in this system, esp if you over fill on a warm day. The fuel tank is only isolated when the PCM is purging the charcoal canister. It appears that the vapor space is approx 2-3 gallons. I base this on the location of the vapor control hose which is just above the fuel pump module toward the center of the tank on the side of the vapor bulge. If you over fill and the raw fuel is higher than this vapor hose you will get liquid fuel into the evap system, however it may be difficult to get this much fuel unless it expands inside the tank. Also if you filled the car on an incline with the passenger side lower than the drivers side you could have a problem, again on a warm day. The question is why do you want to put so much fuel in the system?

 

And what would be a symptom of a "problem"?
What would liquid fuel over-fill do?

I purposely filled REALLY full one time, just to see.
At the gas station I pumped in 15.0 gallons, drove 2 miles to home, then, since it was winter and I had 2.5 gallons in a gas can in the garage for lawn mower use, I figured I should use that 2.5 gallons rather than have it sit in the garage for 6 months and get "stale" ( not sure what that means ).

So, using a 5 gallon gas can that was half full, I slowly poured gas in with a funnel, allowing any air bubbles to come back out. Took about 10 minutes to slowly pour that 2.5 gallons, but it took it all.
The car did nothing unusual after.

Now, for work, I do REALLY long road trips between major cities.
If I can go 575 miles vs. 500 between gas stops, it is worth it to me.
Especially if that extra 75 miles gets me across state lines into a state with gas I like better.

-John

 

I think you meant filling on a cold part of the day and when it gets hotter, the fuel expands.

Since the gas tank seldom fills to the 15 gallon cap. which you can determine by what we discovered here with MTE, trying to put 15 gallons in should not be a problem. Also, the fill connection to the tank is below the vapor space on the side of the tank.

There are a number of reasons that leads me to believe Ford has safe guarded the canister from allowing fuel into the canister. Those valves I posted earlier about in this tread and the design shape of the tank. The manual address expansion in the same paragraph it says those valves prevent liquid gas from entering the canister and the canister purge valve. Filling on a slight slope is how I discovered that 17 gallons could be added to the tank, so Ford must know this is a real everyday situation. Also, my FEH has just got checked out from top to bottom and no problems were found regarding the EVAP system.

It seems overfilling is more of a concern with fuel spills and polluting the air. I researched the manuals and online, and only found one mention of overfilling and the canister. The article was old, so this may have been a problem with older systems. Car makers know that people constantly want to fill to an even dollar amount. Although that's not hard with todays gas prices.

I personally try to get 15 gallon in the tank and I'm happy, but I know 17 gallons has not been a problem for almost 3 years now.

GaryG

 

That is only under certain circumstanses, like filling or during a purge system test otherwise the fuel tank could not vent.

 

I'm not sure you would have a symptom, maybe a strong fuel smell. The results of long term liquid fuel in the canister is the activated charcoal breaks down and flows into the purge componets and clogs valves. Then it will fail a purge test and when its diagnosed you have to amost replace all the componets due to the carbon particals.

Quod possum nolo faco (because you can, you dont want to do it)