Evap, Cannister pellets, and the gas tank

[SpacemanSpiff]

Newbie here so please be lenient...

2011 Tahoe with 145K on it. Having the usual charcoal pellets problem - without dropping the tank I'm pretty sure I've cleared the lines as best I can. The cannister and evap purge valve have been replaced. Still very poor filling. However, I found that if i run the gas in slow it will fill without stopping. Tried that yesterday after the low fuel light came on. I managed to get 15 gallons in before fuel started coming out of the filler neck and spilled on the ground. What gives? Any help would be greatly appreciated!!!!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

The solution to this issue usually involved dropping the gas tank and thoroughly cleaning it out. Also, every tube/line in this evaporative system needs to be blown out with compressed air, and the cannister and purge valve replaced. It appears that you've taken some of these steps, but not all of them.

Clearly, part of your issue still exist.

Other folks who have directly incurred and solved this issue with chime in with their thoughts and perspectives.

20-20 hindsight is great, but not overly useful at the moment. But, in the future, stop filling the gas tank, when the fuel pump automatically first shuts off.

 

[Marky Dissod]

... pretty sure I've cleared the lines as best I can.

... found that if i run the gas in slow it will fill without stopping. Tried that yesterday after the low fuel light came on.
I managed to get 15 gallons in before fuel started coming out of the filler neck and spilled on the ground. What gives?

Unfortunately some critical part of the evap system still disagrees with you / considers your efforts 'not good enough' ...
For the time being, how well can you get along without filling it up, as in, can you tolerate operating under 3/4 tank?
Til you find the culprit or culprit(s), even going over 3/4 full prevents the EVAP system from cycling fuel vapors.

 

[SpacemanSpiff]

Thanks for the reply. I can get along with it fine although I'd like to have it fixed before our trip next year. Does the solenoid play a part in this or will I need to drop the tank?

 

[kbuskill]

Did you remove the line at the purge solenoid at the intake manifold and blow air back towards the canister while you had it disconnected at the canister?

I had pellets all the way up to the purge valve that kept getting stuck in it and causing a leak code.

 

[SpacemanSpiff]

Yes, replaced that valve, too. Drove it a few weeks and those pellets were back. This time used a long nail to get them out of the valve.

Still won't take gas. How hard is it to remove the gas tank?

 

[Fless]

The line from the canister to the purge valve will not affect fueling. But if you keep getting charcoal pellets at the purge valve (on the engine) and have a new canister, that line isn't clear. You have residual pellets from the defective canister, and that will block the purge function (you'll get a code).

 

[donjetman]

How hard is it to remove the gas tank

Easy when the tank is near empty and you have a lift and you don't live in the rust belt.

 

[SpacemanSpiff]

Going to run the tank out and hopefully do it next weekend. Was suggested that replace the fuel pump while it's down. Good idea or no? Tahoe runs good, no issues. 145k on it. If so, what brands are suggested for fuel pump? TRQ? OEM?

 

[Coveman]

I’d be tempted to do the fuel pump too, but on my other burb it took my mechanic 3 tries before the pump was gtg (and it was a delphi that finally worked out). Replacement parts seem to be less reliable these days.

 

[SpacemanSpiff]

Thanks. Fuel light was on yesterday so took it to the gas station - figured I'd try to fill it at the normal rate (full squeeze) and it took 11 gallons before stopping. Got half a tank in but didn't try any more.

 

[SpacemanSpiff]

Thoughts on why?

 

[Marky Dissod]

Thoughts on why?

Thoughts on why ... mind finishing that sentence?

 

[SpacemanSpiff]

Sorry, on why it took 11 gallons before stopping. Gas light was on. So, if the gauge is correct, have half a tank.

 

[Marky Dissod]

Sorry, on why it took 11 gallons before stopping. Gas light was on. So, if the gauge is correct, have half a tank.

Other 1/2 is pressurized vapors. Your EVAP has no room left for any of those vapors, it's already full of liquid gas and/or pellets.

 

[SpacemanSpiff]

It seems I will have to drop the tank - plan on it next week. What is the best tool or way to disconnect the blue clips?

 

[Doubeleive]

I know compressed air is popular but I would try some thin weed trimmer line and clear the line that way. If it will feed thru. I would suspect there is still some blockage.

 

[Fless]

What blue clips? On what part of the system? Evap? Fuel lines?