So I'm new to the Blazer community so hello everyone.
I just bought a 4 door 2001 blazer lt and I'm trying to get saftey and Emissions done but it started throwing the code P0440. It was no surprise to me that it was an evap issue since when I filled up for the first time, as I topped off the tank leaked a bunch of fuel on the ground at the gas station. I assumed it was the vent hose, check it out and it was a little loose so I tightened it, cleared the code, but it came back.

Any thought on on what's going on? Is this a common problem that perhaps you guys are aware of?

thank you in advance!

 

I've got some more info for you guys. So I checked my gas cap (should of done that first, I know) and the o-ring on it was all cracked up. I bought a new one, cleared the code and am now waiting to see if it pops back up again (I assume it will).

I also needed to put some fuel in, so I just but $20 in the tank (3/4 full) and there were no leaks at all.

I also dropped my spare tired, jacked up the rear of my Blazer, and had a look-see to determined if there was any additional obvious problems. First off I was surprised to see that there was no vent tube next to the fill tube like there is in so many other fuel tanks I've seen, Just the fill tube and the tubes coming out of the fuel pump. I tracked one going back toward the rear by the fill tube and connected to a box, that I image is the carbon box I've read about. Anyway, I did notice what could be a fuel stain near and around the fill tube/fuel pump (I'll attach some pics) as well as the fill neck assembly pipe was crazy rusty. Like rusted enough to where I could probably break it by hand. That said, I didn't notice any fuel or fuel stains or smell on or around it (note: I just put $20 in gas no less then 15 minutes before I checked).

My question on this is, when you overfill the tank (which I did just over a week ago) where does the over-filled fuel pour out of?

Here are the pics of my tank and fill tube pipe:

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I would be checking the filler neck and the vent tube and maybe check to see if the top of the tank is leaking or the seams

 

Look at the seal on your gas cap. If you see cracks, replace it.

 

I jumped under the Blazer yesterday, dropped the spare, and took a few pictures. One thing of concern, the fuel neck metal pipe is super rusty. If its not the problem, I'm sure it will be at some point.

I did replace the gas cap and the seal was cracked. I cleared the code and we'll see if it pops up again.

When I topped off the first time, fuel poured out all over the place. I've read this is common and not to top off the tank. My questions is, where does does the overfilled tank dump the fuel? Shouldn't wherever that is be a spot of failure for the evap pressure test?

Here are a few images of the tank and pipe:

 

That is a very rusty filler neck, about as rusty as mine. I don't know if it is what is throwing the 440 code in my blazer but I plan on replacing it anyway. The one in my corolla was way less rusty and it was full of pin holes. I have never replaced one in a blazer, but I did it in my wife's forester and my corolla and it was a piece of cake.

 

So my Check engine light is back up.

My big question is, where does the gas normally spill over when you over fill it?

Where ever this is it has got to be the source of the Evap Pressure issue.

At this point I'm starting to run up against a clock with my temporary tags (Friday). I was thinking of running a DIY smoke test to find out what the F is the problem and replace what I need to. I don't want to replace the fill neck if I don't have to yet. I'd rather my money goes toward whatever is causing this issue and deal with the fill neck later. There is no sign it's the cause of the leak.

Another Q: If the tanks have a tendency to split, where do they normally?

Thanks again for all your guys help. Keep it coming please!

 

your fuel pump isnt seated. also I dont see the lock ring for it

 

Here is a clearer picture of the lock ring. Do you really think it's not seated properly?

 

my mistake, just locks down different. Why no t have someone look while you put gas in?