Charcoal canister

[iboughtatahoe23]

This is an interesting workaround for a faulty evap system, although if the purge valve is commanded open too far the engine will not be happy -- too rich -- and may stall, similar to the behavior when doing a purge and seal test. And it's not always commanded "open" when the engine is running, so YMMV.

I have definitely fueled up multiple times while running and yes, I do notice now when thinking back, that it didn’t click off. And I didn’t notice any symptoms such as stalling or bogging down.

 

[iboughtatahoe23]

Then you'll likely need someone else to blow out your lines for you.

Yay more weekend chores

 

[petethepug]

Oh those charcoal carbon canister pellets. They get in the fuel system like cockroaches. If you haven’t yet replaced your fuel pump, shop RockAuto or Parts Geeks for an OEM lifetime guaranteed unit for about $2h.

Locally or at a dealer they’re about $5h. The fuel tank needs to be dropped and swab’d out of pellets along with the lines blown out. Installing the new f/p & sender is a freebie while you’re tech is in there.

DO NOT use a generic f/p. They fail gradually and will cost you big $ in diagnostics seemingly unrelated to the failing f/p that will be out of warranty. That makes a double ouch for generic f/p replacement.

 

[iboughtatahoe23]

So fuel pump next or blow out the lines? And how exactly do you blow the lines out without ruining crap

 

[donjetman]

So fuel pump next or blow out the lines? And how exactly do you blow the lines out without ruining crap

It's self explanatory when you get into it.
https://www.tahoeyukonforum.com/threads/changing-fuel-pump-sending-unit-bosch.148624/

 

[houstontaylor]

You can just disconnect the tank vent line at the charcoal canister and fill it up. If it works then without shutting off then you know you still have a problem with the system, like with the vent valve or clogged lines.

 

[RET423]

The filter medium from the cannister cannot get into the fuel tank when the cannister fails & the fuel pump has nothing to do with the EVAP system so I wouldn't start changing those parts

The tank vents to the fuel nozzle when filling with fuel, not through the EVAP system, there is a path to the fuel nozzle boot from the tank so air displaced by incoming fuel can escape; if that path is restricted the displaced air can only escape up the fill pipe & cause your symptom

That path is either a small external hose from the tank to the filler neck or a seperate vent contained inside the fill pipe. In either case it vents above where the fuel nozzle releases the fuel into the fill pipe

That's where I would be looking, good luck!

 

[Rick10Tahoe]

When I replaced my canister, I vacuumed out the lines with a shop vac. I vacuumed a lot of charcoal beads out of the lines going to the gas tank. It was easy and very necessary part of the replacement