Fuel filler neck small leak?

I get the 0456 code which is small emissions leak detected on my 2003 all the time. I just reset it with my ScanGauge until two days later when it comes back.
I get a fuel vapor smell around the filler door so I know there is something going on back in that area.
Had the dealer smoke test, first time said it was the gas cap and I ate the astronomical cost of a new OEM cap to be done with this. Well, that was not it so back to the dealer and now they say the filler neck is where they saw the smoke. They want $400.00 to replace, I told them no thanks!
So, doing a deep dive into this fuel filler assembly I cannot see for the life of me any pinholes, rust or any possible source of a leak. It all is a rather simple looking assembly.
Has anybody out there had something similar? Seems to me it would be obvious but I am not seeing it.

 

Were they going to refund you on the miss diagnosis time and cap?

 

They ran a second smoke test for no charge, at that point they now said it is the filler neck. This is why I trust no one to work on my truck, but I don't have the ability to smoke test so I was stuck.

 

I have seen these videos, thank you. It is a shame I have to do it myself after I paid someone else. I just do not understand where it could be leaking on a filler neck.

 

Could just be a weather split in the vapor overflow tube that leads back to that area, these trucks are old.

 

I made a deal with a Mom and Pop shop that knows I want to work on mine as much as I can. They'll smoke a vehicle for 50 bux and show me what it;s doing.

Never stepping foot on a dealer lot in my lifetime again.

 

Can you be more specific? Exactly where are you referring to? There are three different tubes that attach to the main tube.

 

I learned my lesson. The problem is they are righ next door to my work so it is very convenient.

 

There's a rubber hoses on the smaller tubes of the filer neck. They may be cracked

But if you are talking about the bigger main tube, mine was cracked where it joints with the plate that is bolted onto the tank. And I've also seen two trucks with this issue as well.

I did fix mine by cutting off the external part of filler neck from the plate then welding a bit of pipe in it's place. Then I did cut off the flex section from the separated filler neck and put a section of vinyl tubing in it's place then joined both ends together. Then added tubing clamps to hold everything in place. Of course, you'll need to drop your tank and then remove the filler neck to do that.

I've also seen a truck where the tank had pinholes right below the bolted-on plate. If you look closely, you will see that the plate isn't flush with the tank, it's a little bit raised. It had tiny holes right there, where it was rising from the tank. I don't know what the person did. He just thanked me and said he'll take care of it. I believe he put some JB weld there.

 

I’ll look again at the hose.

Supposedly the smoke was up to the top portion of the filler tube, hence the reason why they replaced the gas cap the first time. That is what frustrates me is now I have a hard time believing anything they still me. I hope it is not down by the tank..

 

Oops, I see you have a 2003. Since it isn't the same than 1995-2000, there's no plate. The filler neck is directly connected to the tank with a flex tube. It may be cracked where the little section of tube comes out of the tank to get into the flex tube. If that's the case, well, I guess JB weld or something similar would do the thing instead of replacing the tank.

 

Any rubber parts.
I guess you'll have to drop the neck and go over it with a fine tooth comb.

 

So that is part of the confusion. The dingbats said the smoke was up high away from the tank. But who knows. Down by the tank makes sense.

 

Back to smoke. Finding someone to do it.

 

yea, I'm afraid the easiest thing to do is re smoke it.

 

I am looking at various smokers on EBay. That way I can take my time and find it myself.problem is using the smoker once and most likely never again..

 

Or just take it apart and look closely BUT I had a leak that didn't show 'til it was flexed. (different vehicle)

 

If you are lucky, it will be the flex tube that's cracked. it's replaceable

But if smoke does come higher on the filler neck, near the gas cap, like they said, I bet it has something to do with that plastic cap thing there:

 

That;s why I gave a link to make one.....free. You don't need a compressor. An air pump will do and a 9V battery.