'02 TB hard gas refills, ideas?

[02FailBlazer]

'02 Trailblazer, 4WD.

My TB has had a hard refill problem for a long time (well over a year) - when refilling the tank, the pump will click off almost immediately unless I reach in and hold the pump seal away from the filler neck. I just replaced my gas tank, and neither my old tank nor this tank appeared to have a stuck check valve - both moved easily by hand. I replaced the vapor canister vent valve (the boxy/rectangular part that hangs near the filler neck) and that didn't solve the issue either. I also went through several purge valves (the one attached to the drivers side of the engine) with no change.

There are no codes, and the only leak found when I had my EVAP system smoked was my inlet check valve seal, which has been remedied and the associated EVAP code is gone. I'm out of ideas. What else could I try? Blow out the EVAP lines? I did overfill my tank a few times due to this issue, so maybe I killed the vapor canister?

 

[movietvet]

May not be the problem but if you did overfill the tank "a few times" means, yes, replace the cannister.

Blow the lines out because I would have thought you would have blown them out already, what with the valve replacements.

 

[Mooseman]

Agreed. The usual causes of this is a blocked canister, defective vent valve (stuck closed) or blocked vent line. There is a filter at the end of the vent hose that could also be caked with dirt. Since the tank is "new" and you have the same problem, I would look upstream from the tank's vent hose. Next time you go for a fill, disconnect the hose going into the canister from the tank. If that seems to fix it, then something is blocked downstream of that hose.

The check/rollover valve only comes into play when the tank is full.

 

[Matt]

When I had this problem with my 02 I had to replace the fill tube because it had a big kink in it. IIRC they shortened the fill tube in later year, pretty sure I got an 05 or 06 from the junkyard that worked great.

 

[Srmva]

'02 Trailblazer, 4WD.

My TB has had a hard refill problem for a long time (well over a year) - when refilling the tank, the pump will click off almost immediately unless I reach in and hold the pump seal away from the filler neck. I just replaced my gas tank, and neither my old tank nor this tank appeared to have a stuck check valve - both moved easily by hand. I replaced the vapor canister vent valve (the boxy/rectangular part that hangs near the filler neck) and that didn't solve the issue either. I also went through several purge valves (the one attached to the drivers side of the engine) with no change.

There are no codes, and the only leak found when I had my EVAP system smoked was my inlet check valve seal, which has been remedied and the associated EVAP code is gone. I'm out of ideas. What else could I try? Blow out the EVAP lines? I did overfill my tank a few times due to this issue, so maybe I killed the vapor canister?

I would check for a failed(stuck closed) vent valve

 

[02FailBlazer]

I would check for a failed(stuck closed) vent valve

I can pull it off and bench test it but it did this with my old valve and has been doing it right from the start with the brand new one I replaced it with to try rectifying this issue.

 

[02FailBlazer]

When I had this problem with my 02 I had to replace the fill tube because it had a big kink in it. IIRC they shortened the fill tube in later year, pretty sure I got an 05 or 06 from the junkyard that worked great.

If you mean the rubber hose that connects the gas tank to the metal filler neck, I replaced that when I reinstalled the tank. Replacement part was the Spectra FNH140, has the check flapper in the middle. Used brand new Norma hose clamps too.

 

[movietvet]

If you mean the rubber hose that connects the gas tank to the metal filler neck, I replaced that when I reinstalled the tank. Replacement part was the Spectra FNH140, has the check flapper in the middle. Used brand new Norma hose clamps too.

Hopefully, in the future, you will get better at sharing everything you did and parts used, when listing out all you have done for a problem, before you ask here. It helps with the "thinking thru the systems" process. I still say the lines should be blown out, especially with a likely cannister problem, if not replace the lines altogether.