Slow fuel fill - 2005 Yukon Denali 6.0l

DarthDaddy98 · July 13, 2013

Hi everyone - this is my first post here so please be gentle....

I have read every thread I can find on the slow fuel fill problem, but I have not seen anything like what I am experiencing.

Mrs has an 05 Yukon Denali, 6.0l She started complaining that it took forever to fill the tank, so I started investigating. No DTC set, but there was a pending P0455.

I have replaced the

ACDelco 214-2147 OE Service Vapor Canister Purge Valve (the one by the vapor canister, behind the fuel tank)

and

ACDelco 214-1105 Valve Assembly (the one on the top of the engine, under the plastic "Vortec" shroud. Having said that, the fuel fill problem remains, but no code is set.. Now the odd part: When I replaced the vent valve on the front of the engine, there was a small number of small black pellets that came out of the old valve when I removed it. I can only assume these are charcoal pellets from the Vapor Canister. When I shake the hose that was connected to the valve, i can hear more of the pellets inside, but I can't get them out just by shaking the hose. Now that both valves have been replaced, I can only guess that the hose from the canister to the engine is clogged with those charcoal pellets, and that is causing the tank not to vent correctly. Can someone please tell me how I can clear that hose?

I have tried disconnecting the other hose (not the one that goes to the canister purge valve) from the canister and trying to blow air through it, but that just left me with a small pile of charcoal pellets under the vehicle that cam out of the canister itself. Nothing came out of the hose.

I expect that also means the canister needs to be replaced as well. Thoughts anyone? I'm stumped. Any suggestions at all will be greatly appreciated.

Thanks!

Doug_Scott · July 13, 2013

Where does the line that has the pellets in it go? If it is from the fuel tank, you could try to remove the line from the tank and from the canister and blow through it. If you cannot get to the hose where it connects to the tank, you could find a hose connector at your local auto parts store and just cut the line close to the fuel tank and clear it out, then use the connector to reconnect the tank.

Don't think pellets should be in the line though. You will need to correct the reason for that happening. My guess would be that you need to either replace the canister, or replace some type of filter inside the canister. Note that this is just a educated guess to maybe give you some idea of what questions you need to ask, please confirm before you start throwing money at it.

DarthDaddy98 · July 14, 2013

That's the confusing part. I found charcoal pellets in the vent hose at the front of the engine, and some at the canister end as well. When I blow air thru that hose from the front to the back, pellets come out of the Evap Canister if I disconnect the hose at the evap canister that looks like it goes to the front of the vehicle. I get pellets coming out of the canister, not the hose. I don't think that's the hose that goes to the front of the vehicle because it routes over the top of the tank.

I need to know where those hoses go. I suspect they all connect at the top of the tank somewhere, but I want confirmation before I have the tank pulled. I'm not doing that myself.

Thanks!

Stich56 · October 25, 2015

I have some problems as Darth. Replaced solenoid at manifold, vent solenoid,, and carbon pellet canister which was loosing pellets. Line to manifold is loaded with pellets and they will not blow out. I cannot trace path back to rear of truck. Does anyone have a detailed diagram? With known endpoints maybe whole line could be replaced with one continuos hose. Anyone else been through this?