Hello all I had to replace the elec. fuel pump on my 04 Trailblazer when dropping the tank put a hole in it cutting the rusted out strap bolts I bought a used tank , a new filler neck and fuel pump. After that I cannot put gas in the tank the pump shuts off immediately no mater how slow I pump. I can fill a 5gal gas can and it goes in as fast as I can pour using a funnel so there is no restriction there it is a vent issue so I bought a new tank vent that attaches on side of tank no change. I did wash out the tank with soap and water and rolled it around upside down and all could that have messed up one of the other sensors on top of the tank there are 2 or 3 small round sensors on top of the tank that I don't know what they are. I will attach picture of vent valve I changed. Any suggestion would be appriciated. Thanks for reading
Gas tank venting issues can't fill
- Thread starter johnny be good
- Start date
Mooseman
Moderator
Ah yes, the infamous can't fill the tank because it clicks off issue. Lots of info out there on that. One thing it could be is the vent valve which you already replaced. The other is the charcoal canister is plugged.
Thanks for the reply I have been reading some of the other threads. Just wondered what the other sensors where on top of the tank if maybe the water when washing out the tank may have screwed them up
Mooseman
Moderator
Just one sensor up there and that's the tank pressure sensor. Has nothing to do with venting or your problem.
on mine, it was the charcoal canister was plugged. i'd taken the vent line off going to the tank and blew through it and could hear it blowing into the tank. i took off the vent line going to the vent valve and could blow through it fine. The only thing left that it could have been was the charcoal canister being plugged.
aaserv
Member
You can ck the charcoal canister by comparing its weight against a new 1. As the charcoal gets saturated with fuel it weighs considerably more than a new 1.
Maybe someone could post the weight of a new 1 so it would be handy for future reference ?
Also as a another tip....the way these canisters become saturated is by "topping off" the tank when refueling. All your doing is forcing fuel back down the vent hose and into the canister.. NEVER top off a modern fuel system...
Maybe someone could post the weight of a new 1 so it would be handy for future reference ?
Also as a another tip....the way these canisters become saturated is by "topping off" the tank when refueling. All your doing is forcing fuel back down the vent hose and into the canister.. NEVER top off a modern fuel system...
Mooseman
Moderator
Another way is when the rollover/tank full valve is broken and allows the fuel to fill all the way to the top. That's my problem right now with the Av. Have to replace the tank to fix this particular problem (not yours).
I have been really busy with another project so I haven,t had time to check any of the suggestions yet that you all have posted for me to check. I will be working on it next week and let you all know what was found Thanks again for all the help I really was lost.
OK All I have finally after filling gas tank for months with a gas can decided to look into my problem. Turns out I bought a new filler neck which is in three pieces, the first part where you stick the pump in ,the second is a rubber hose and then the last piece is metal again to the tank. I remove the first part where the pump goes in and compared it to my original so far I see that the curve is more of a bend on the new one so I put back on the old one and it fills just fine like it should. My old one is to rusty and mount tabs are broken off so what I am going to do is take the new one and heat it up and straighten a little to match the old one and see what that does.
At least I now know where the problem lies if straightening doesn't do it then the small vents in that piece are screwed up we will see and I will keep updating.
At least I now know where the problem lies if straightening doesn't do it then the small vents in that piece are screwed up we will see and I will keep updating.
Oh Well did not work going to put old one back on and be sure that is it and if in fact that is it I will look for a factory GM one. I just don't see any difference between old and new except new one says Taiwan. Will keep posting results
Mooseman
Moderator
Did you check the charcoal canister? As a test, you could disconnect the hose that goes from the tank to the canister and try to fill. If it fills OK, your canister is plugged.
Thanks Mooseman for the reply I never had problems until changing the filler neck and when putting the old one back on seems to have solved the problem I will put the old one on again just to be sure and if that is not it I will look into that canister I did already change the vent solenoid. I don't want to try two things at once just to see what is actually causing the problem