2005 Chev 2500HD - 6.0L Refuel Problem

[asample]

Looking for a little insight.
Have 2005 Chev 2500HD with 6.0L (U) engine. All of a sudden it won’t take gas.
Had 2 codes P0455 -Evaporative Emission (EVAP) Vent System Performance and
P0455 - Evaporative Emission (EVAP) System Large Leak Detected
Smoked for leaks. None found. Monitor data. Unable to get EVAP purge valve on intake to respond. Replaced valve and cleared codes. Test drive. Attempted to fill with gas. Took about 3 gallons very well then regurgitated out fill pipe.

Removed EVAP canister and vent valve. Cleaned and flow tested components and lines. Did have considerable amount of dirt in valve. Reassembled and again attempted to add gas. Took about one gallon and puked back.

Customer had to have vehicle last night so told them I would do more research before removing tank.

Most NAPAFix fixes were vent control solenoids. One was fixed by replacing tank.

There is a tsb listing a service kit to relocate vent valve above transmission.
Any ideas??

[ricmorin]

Usually it is the vent valve on these. If the valve is working, maybe the line is plugged.

[a&mauto]

Arlin, with your scan tool, command the vent open & closed. Blow thru a clean piece of fuel line connected to the valve and see if it does open. Blow thru the line going back to the tank to see if it is clear. We have even had to disconnect lines at the gas station just to see what helps. We recently found a slightly kinked line on a Ford that didnt look like it would cause such a big problem but it did. The line that was the problem allowed a raised section of the tank to bleed air so that it could fill. I guess if you are pumping in a few gallons a minute, all that air (vapor) needs someplace to go.

[steven kiser]

quick test is to run it with gas cap off. it sounds like ric hit it. woops, i misunderstood the original post. yes the vent valve is most likely stuck. check the exhaust port on the valve. as wild as it sounds i've had spider webs cause problems.

[asample]

Thanks guys. I will try to get the vehicle back in here in a day or so and then let you know more at that time.

Arlin

[steven kiser]

another question. did this truck possibly have an after market dump body put on it? i've had a bunch of these that the bracket that supports the filler tube gets bent just enough to puddle gas in it causing a back up. if not, it's probably on top of the tank. we've found it easier to lift the body than drop the tank.

[asample]

Fixed, I think!

After having the truck for a few days after telling them tht we would have to remove the tank for further testing they returned to say that now it seems to be taking fuel as it should. Maybe after cleaning all lines and allowing some circulation through them the problem has been resolved.

The other good thing about this situation is she paid for our diagnosis with this good report.