Hi all!

I have an issue with refueling, it takes a really long time to refuel the tank. If I go too fast, it makes the pump kick out and stop. To me it seems like the tank is not venting properly, and air has to escape through the filler neck, which then backs it up with fuel. From what I've read, this could be an issue with the vapor canister or the vapor canister purge solenoid. I removed the whole vapor canister assembly from the truck today and cleaned it. All hoses were fine, the solenoid was not clogged and the dust separator box and vapor separator were also easy to blow through. The canister itself did allow air through, but felt restrictive when blowing through it. I have no idea how well air should flow through it though so I don't know if it's too restrictive or not.

How do I properly diagnose the vapor canister and determine that it indeed is clogged to the point of causing the issue of slow refueling? I don't want to sink 200 bucks into a new canister if I don't need one....

And is there anything else that can cause this refuel problem?

 

Have you tried turning the gas nozzle to the side? That sometimes happens to me when pumps run too fast and turning it to one side or the other usually solves the problem. If you still have a problem then yes, it's likely the vent tube not venting properly.

 

Is it supposed to vent through the canister? Or is it supposed to vent through that thin tube that runs alongside with the filler neck and connects at the inlet?

I've seen some that claim the canister will cause slow refuel when clogged, but it doesn't really make sense to me, specially when seeing that smaller tube running up along with the filler neck.. Some said that disconnecting the line coming from the tank to the vapor purge valve under the hood allowed them to refuel normally, so I'll try that as well.

 

FWIW- TSB on slow refueling:

http://ww2.justanswer.com/uploads/s4...B_07-15-01.pdf

I have this problem with my E350. Intermittent for me and has absolutely nothing to do with the gas station pump angle.

 

I'll check the vent tube that goes from the canister and terminates up at the filler neck. It started raining when I was doing this yesterday so I didn't get to it. Hopefully I'll find the clog in something easy. It's easy enough to replace the whole vapor canister assembly at 200 bucks, but my gut feeling tells me that it won't necessarily fix the problem.....

 

There is air no vent tube there like that. The fuel fill air venting is done through the EVAP system.

 

Then what is this tube?

 

That's an intake vent tube for the EVAP system. It keeps vapors from escaping the fuel filler should the fuel cap be removed while the engine is running. Those #9 valves, one of which the hose in question connects to, is a one way valve that allows air into the tank, not out. To vent during filling air has to be able to escape and it cannot because of the #9 valve.

 

Ok, so as a part of confirming the diagnose, if I disconnect the line at the number 4 purge valve and it then refuels normally, then the problem must be with the EVAP assembly?

 

Not really because if there is a clog between there and the tank it won't make a difference. You have to disconnect the line from the left side of the #2 fuel tank pressure sensor, or at the tank itself (#3 valve).

 

Well, that's what I wanted to rule out.. If it refuels normally with number 4 disconnected, then all the lines from the tank to the evap where all the lines merges, and up to the no. 4 purge valve must be clear, and thus not part of the problem. Right? I.e., the only place left that can cause the problem would then be the EVAP assembly.

 

100% correct.
But if the problem persists, then you've got to start digging into all of the EVAP hoses and look for a clog.

 

Great, then I know where to go from here. When talking about the vapor canister itself, how open is it supposed to be? How do I know it's too restrictive or clogged? I was able to blow through it, but it felt like blowing through a thick filter.

 

Funny you should say that because you were. Yes there should be some resistance in one direction, but nothing should flow in the other direction.

 

Ok, then I'll have to assume that the vapor canister itself is not clogged. I know where to go from here. 2 checks to do, then I should know a lot more about where the problem is.