Denali12
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Another look.. This is my actual vehicle when I pulled the wheel.
Fuel Filling/EVAP issues tried everything please help
- Thread starter MRPRO
- Start date
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The same thing happened to me when my canister failed and blew pellets through the lines. Below is the advice I can give given what you’ve already done
1- inspect your purge and vent valves for proper operation and to make sure they’re not clogged. If you had pellets in your lines after the parts had already been replaced then some may have gotten into your replacement parts. This occurred twice on my new purge valve, so I had to dig them out for the valve to resume operation
2- check your canister for fuel. It may be clogged. If so, you’ll need to blow it out. On my 2005 Tahoe z71, I found that I cannot park on an incline with the nose up and a full/semi-full tank or fuel will travel up the lines and eventually fill the canister. This is just my experience, and I also haven’t done the updated vent line routing like others.
3- I also checked to see if the system was clogged by carefully blowing air toward the tank and not just away from it to try to dislodge any pellets.
4- there is a vent line that travels along the fill hose - check that for proper venting too.
With these ‘fixes’, I haven’t had issues with my Evap system since (knocking on wood!).
1- inspect your purge and vent valves for proper operation and to make sure they’re not clogged. If you had pellets in your lines after the parts had already been replaced then some may have gotten into your replacement parts. This occurred twice on my new purge valve, so I had to dig them out for the valve to resume operation
2- check your canister for fuel. It may be clogged. If so, you’ll need to blow it out. On my 2005 Tahoe z71, I found that I cannot park on an incline with the nose up and a full/semi-full tank or fuel will travel up the lines and eventually fill the canister. This is just my experience, and I also haven’t done the updated vent line routing like others.
3- I also checked to see if the system was clogged by carefully blowing air toward the tank and not just away from it to try to dislodge any pellets.
4- there is a vent line that travels along the fill hose - check that for proper venting too.
With these ‘fixes’, I haven’t had issues with my Evap system since (knocking on wood!).
PNWYukon
Full Access Member
The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.
I had the same problem with a charcoal canister that came apart. I blew air thru the line from the canister to the purge solenoid many times and still had evap system codes and would find pellets in the valve. There is a connection in the vent line at the rear of the intake/top of the bell housing area. Due to the way the tubing is cut the only way to clean all the charcoal pellets out was to disconnect the line and blow out each line separately. If I recall correctly, the line is metal steel braided along the side of the transmission and connects to the plastic tubing going up to the purge valve.
Did the whole thing again today. Decided to test the new vent valve solenoid I got from Autozone as well as the old one I removed. Applied voltage. The old one clicked. The new one did nothing. I was able to blow through the old one but not the new one until I applied 90 PSI of air. So the "new" vent valve solenoid was stuck closed. I reinstalled my old one after I cleaned it and returned the Duralast unit. I also dropped the tank and cleaned out all the lines and everything else just because I was there and for good measure. For the first time in weeks I was able to fill it up with fuel with no issues.
Here's what I think happened. I overfilled the vehicle with fuel once about two months ago which was the last straw for a 16 year old carbon canister. That sent carbon pellets through the lines which caused restriction and started this whole thing.
Next time I went to fill up I couldn't and did some internet searching and found that the vent valve solenoid needed to be replaced.
I purchased one from Autozone and replaced it. Didn't fix the issue at that point because nothing else had been blown out or replaced.
Next thing I did was the carbon canister. Still no luck as the lines were still clogged.
Next was the purge valve. Still no luck and pellets kept coming out of that line.
Next I dropped the tank for the first time and cleared out the lines. Was able to fill up again this one time.
Next time I went to fill up same thing happened again and couldn't fill. Didn't know it at the time but the new vent valve had already failed. Subsequently this led to me chasing my tail dropping the tank and cleaning the lines two more times to no avail ignorantly assuming that my "new" parts were functioning properly.
Today on a whim I decided to test the "new" vent valve and found it was garbage and didn't work.
Please learn from my mishaps as this was frustrating.
Here's what I think happened. I overfilled the vehicle with fuel once about two months ago which was the last straw for a 16 year old carbon canister. That sent carbon pellets through the lines which caused restriction and started this whole thing.
Next time I went to fill up I couldn't and did some internet searching and found that the vent valve solenoid needed to be replaced.
I purchased one from Autozone and replaced it. Didn't fix the issue at that point because nothing else had been blown out or replaced.
Next thing I did was the carbon canister. Still no luck as the lines were still clogged.
Next was the purge valve. Still no luck and pellets kept coming out of that line.
Next I dropped the tank for the first time and cleared out the lines. Was able to fill up again this one time.
Next time I went to fill up same thing happened again and couldn't fill. Didn't know it at the time but the new vent valve had already failed. Subsequently this led to me chasing my tail dropping the tank and cleaning the lines two more times to no avail ignorantly assuming that my "new" parts were functioning properly.
Today on a whim I decided to test the "new" vent valve and found it was garbage and didn't work.
Please learn from my mishaps as this was frustrating.
ivin74
05 NBS Nali
That is a ****** design, is that design only on the nnbs suvs?
PNWYukon
Full Access Member
Good job! Amazing that you kept at it and found that junk "new" part was causing you more problems.
Well at least it’s solved for someone. I fixed it on Monday and someone stole it yesterday.
Oh crap! I am so sorry!
ivin74
05 NBS Nali
That sux, did you have anything valuable or desirable that would make then take your ride?
Where do you live? We need to stay away from that area, lol
treehan77
TYF Fiend
When I went through this I ordered an AC delco valve and it didn’t work out of the box when I bench tested it lol
hawaiiantahoe808
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Good thing i check this category.. i recently put a 8" lift on my 05 suburban and when i go to put gas i have the same problem .. never happened before til i installed the lift ... any help would be greatly appreciated
shartymcqueef
TYF Newbie
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Easy way to fix this at home for free:
One cause among many. If the pellets have migrated into the evap lines, to the purge solenoid or the vent valve, you'll have more work to do. Fix it right.
ilikemikes
Member
Gentlemen, how would you start problem solving this without replacing everything? Gas is back flowing on last couple of trips to the gas station. No error codes except "tighten gas cap". This thread was very helpful. 2011 Tahoe LT w/3inch body lift. TIA
I would recommend starting a new thread for your issue in the correct year section for your Tahoe. There can be variations in the evap systems and the answers you want will be more targeted in the correct year forum.
