05GT-O.C.D.

Well, here's the Cliff's Notes. I have an early 05 w/ the first generation gas tank. Regardless of how full or completely empty the tank is, getting gas has always been a chore. Pump... click, Pump... click, Pump... click... you guys know the routine.

Well I took it in finally and had the tank replaced as I figured Ford would've had this problem licked by now. Stupid me. So I go to Sunoco with high hopes and start filling up. IT WORKS! I walk away relieved and a minute later 'Click'. I walk back over and I've got about 9 gallons in. I try to fill back up and it won't take another drop and starts to flow out... it's FULL. I get in and drive off and the needle reads 1/2 tank.

Frustrating.

So I got to thinking what could be going on and got off my butt and crawled underneath. I see the obviously new tank under there and scratch my head (after I banged it ). Then I decided to knock on the fuel tank. On the left side I hear - thud, thud, thud - sounds full and solid. I shimmy over to the passenger side and knock - ting, ting, ting - sounds empty! Got me thinking what's going on and I have a possible idea. Here's what I think's happening.

Here's my crude drawing of the tank, looking from the rear.


Now, when you start filling, I think all is well and as the gas fills the void in the tank, the air vents back out the filler tube:


As it fills past the filler tube, the air begins being pushed over into the right tank and compresses the air there:


Eventually it fills up past the filler tube and the air has nowhere left to go, so it holds the gas in the left side of the tank. This would explain why I'm only able to fit 1/2 tank in and not a drop more, and it also explains why the left side would be full and the right empty. So I assume to prevent this problem there is a vent on the passenger side. I see a hose there that runs back to that hunk of emissions crap under the spare tire. If the vent is blocked, then this explains my problem... right???


Ideally I think that if I'm guessing right on these things, this is how it's supposed to work -



Does this make sense to anybody??? If it's right, then I assume we have 2 fuel pumps? One for each side?

If I AM right - then what should I start doing to find this blockage? Is there a check valve in the vent hose? Something under that black perforated steel under the spare tire??? A kinked line??? Anybody???

Thanks!

theedge67

I think there is a tube or something at the bottom of the tanks to help transfer fuel from one tank to the other. I'll see if I can't find a real diagram somewhere though.

05GT-O.C.D.

I didn't see anything like that. But then again, laying on my back in a 13 degree garage at 2:30am I could've missed it.

theedge67

Actually it does not look like there is a connector tube. Here is the best diagram I can find.

05GT-O.C.D.

Good find. I guess I could get it to the faux full level, then disconnect the Vapor tube (15) and see if it would take another gallon to troubleshoot??? (wearing safety goggles, rubber gloves, old clothes, and then reclipping before going anywhere ) Bad idea?

2005mach1

while the therory is good, thats not the problem. there is a vent valve on both sides of the fuel tank. After having a hole in the tank, and removing it, i have seen the hoses in the fuel cell to work with the vent.
I have seen where the evap canister can also be a problem. I dont have the answers, but it not a tank vent issue. see pics attched.

05GT-O.C.D.

Where's the vent on the left tank (right side of your pic)? If it's at a level below 'the hump' then my theory would still be good. Wouldn't it?

Also, how the heck did you get that hole in your tank?

2005mach1

the fuel filler has an attched vent, the opposite side vets into the evap canister.
at 130 mph on a dyno the driveshaft came apart. going through the fuel tank , exhaust paipes, emergance brake cables. Ford didnt install C-clips on the outside of the driveshaft U joints on some Mustangs. Sucks to have one of those.

05GT-O.C.D.

Correct. So the left side fills up fine, but eventually will no longer vent as the fuel moves past the vent level, and if then the right side vent is blocked, then that would create the problem... at least in my mind.

Bummer. But better on the dyno than the freeway. (not that anyone would do 130 on the highway )

LBJay

My suspicion that this convoluted P-trap arrangement is the source of the problem.

And that they can't solve that problem because it must route that way because of the basic car design. That's why we haven't seen a fix. Only a redesign of that area in a future model could solve it.

05GT-O.C.D.

I thought that as well, but I'm 99% sure of my fix.... pending tonights investigation... stay tuned for news at 11:00.

SixtySix

I get what you're saying, but that doesn't hold up to why only "some" cars exhibit the problem. If that were the case, we'd all be experiencing the issue.

mustangman1960

My car has the slow fill issue as well. The fill-click-fill-click only seems to occur at certain gas stations. I fill up most often at the same Kangaroo's service station and I have the problem. I turn the pump handle 90 degrees and the fill problem goes away. I have not run into the fill problem at any other service station.

I think the problem has to do with the routing of the filler tube to the tank or perhaps the filler tube is too small in diameter.

gloryboy

found this on another forum, not sure it will help but may be worth a shot.......
http://s197forum.com/forum/showthread.php?t=591

theedge67

As long as I fill at the slowest setting at the pump, I usually don't have any problems. It takes a few minutes to fill, but better than 15 minutes if I try and go too fast.

Glenn

I wonder if there was a 2 inch tube between the two tanks in the lower part of the tank if that would help anything?

05GT-O.C.D.

I believe the answer to that question is yes. We'll find out this weekend if I'm correct, it's supposed to warm up to a temperature that won't put me at risk of hypothermia when working on the garage floor.

2005mach1

Guys i have had the tank in my hands, 2 tanks to be honest. If ford could replace the hose, instead of a $300 fuel tank it would have done it. These was a redesign in the fuel tanks, and venting process on the fuel filler side. I dont know much else, but its not an issue of fuel filling on half the tank and getting too much pressure on the oppsite side.
I'll lets wait to see what his fix brings.

05GT-O.C.D.

UPDATE!!!

FIXED!!!

(At least for now )

I took apart the entire line from the tank back to the canisters. I took out all the canisters and checked them out. I paid special attention to that 'filter' box that is mentioned in that other thread and I don't know that it was specifically the problem. When I took it out, I was careful to gently blow through it (with my mouth), and felt no restriction there at all. Truth be told, I didn't find much of a restriction anywhere... which was frustrating. So I took my compressor and blew air through every piece of plumbing and canister then reassembled everything, completely stumped as to what else the problem could be.

I went back to the same Sunoco, stuck 'er in, and hit the fuel full blast... fully expecting to either get sprayed in gasoline or hear the infamous click. It goes, and goes, and goes... ... then clicks.

I pay, get in, and ...

... FULL TANK!

That's the first time that's happened in over 2 years!

I don't know where the restriction was, but it was somewhere on that right side of the tank, opposite the filler. I didn't mess with anything on the left side at all. It was definately a vent issue on the right side of the tank keeping fuel from getting there.

But - here's the odd thing - when I was reassembling everything I found my utility knife sitting in a pool of water that had a hint of a gas smell to it. I didn't notice exactly which pipe it came out of, but it got me thinking. I think somewhere, the actual problem was a condensation build up in one of the plumbing lines, likely in one of the bends - almost like a plumbing trap under your kitchen sink.

So I'm relieved and disappointed. I'm relieved because now I know how to quickly fix the problem should it reoccur. I'm disappointed because I was hoping to come back and tell everyone just where the problem was and how to fix it since I know it plagues a lot of us.

If anyone else tries this, pay attention for any liquid to come out of any of the lines - I was working in a poorly lit 30 degree garage.

theedge67

Glad it got fixed for you! Kinda sucks that you didn't find anything though, that is frustrating.