Fuel Filler Blockage (1 Viewer)

[EdsCruisin]

Last week I suddenly ran into a problem. Wednesday night I filled my gas tank effortlessly, to prep for a road trip with the camper on Thursday. During the trip I stopped to fill again and the pump kept shutting off.

It seems that I could only fill the filler tube and then wait for it to drain slowly into the tank. BTW that's less than a tenth of a gallon at a time in a 24 gallon tank! I was fortunate to find some pumps that used less pressure, but it was a true patience tester.

Has anybody experienced and solved this problem?

 

[FlammableFishie]

Have you tried checking to see if you actually do have a blockage or if it's just something else?

 

[midwest2]

Last week I suddenly ran into a problem. Wednesday night I filled my gas tank effortlessly, to prep for a road trip with the camper on Thursday. During the trip I stopped to fill again and the pump kept shutting off.

It seems that I could only fill the filler tube and then wait for it to drain slowly into the tank. BTW that's less than a tenth of a gallon at a time in a 24 gallon tank! I was fortunate to find some pumps that used less pressure, but it was a true patience tester.

Has anybody experienced and solved this problem?

I have seen this exact problem on several Ford Crown Vics. On that model there is a flap at the bottom of the filler tube that keeps fuel from gushing out during a roll-over collision. When that flap fails you get your exact problem. I'd assume the LC has the same setup.

 

[Trunk Monkey]

Have you filled again since that happened? I bet it was the pump, not your truck.

 

[EdsCruisin]

Have you filled again since that happened? I bet it was the pump, not your truck.

I thought that at first too, and moved to another pump, but it repeated. And then towing at 8-9 mpg for several hundred miles in each direction I had many more opportunities to try and the same problem persisted.

 

[paflytyer]

I thought that at first too, and moved to another pump, but it repeated. And then towing at 8-9 mpg for several hundred miles in each direction I had many more opportunities to try and the same problem persisted.

Sounds like a charcoal canister or EVAP issue. Once the charcoal in the canister becomes saturated with fuel it will swell or expand and block the vents. When you try to add fuel, the vapor has to go somewhere but the blocked vent lines won't allow it to escape and the fuel can no longer displace the air in the tank.

Do you notice a fuel smell? Especially on hot days or at altitude? To me, it smells like glue or something chemical..... But kinda gassy..

Do you sometimes add an extra splash of fuel after the pump automaticity shuts off at fill up?

 

[EdsCruisin]

Sounds like a charcoal canister or EVAP issue. Once the charcoal in the canister becomes saturated with fuel it will swell or expand and block the vents. When you try to add fuel, the vapor has to go somewhere but the blocked vent lines won't allow it to escape and the fuel can no longer displace the air in the tank.

Yeah, I was wondering that too, and disconnected the EVAP line from the charcoal canister, and I was able to blow through it and successfully blow back into the fuel tank. But it did not make a difference.

I'm glad about that, because I hear those canisters cost hundreds.

I just downloaded the fuel tank and EVAP system specs and diagrams. I see a flexible hose from the filler tube to the tank, and a removable filler pipe assembly from the tank, so I am hoping this will be a serviceable part issue.

 

[Slickspawn]

One thing you need to check is the fuel vent fill hose. Sounds odd but spiders love making little nests in there that prevent venting and make filling your tank nearly impossible.

http://articles.latimes.com/2011/mar/03/business/la-fi-mazda-spider-20110304

 

[EdsCruisin]

Update:
We did a smoke test and found all the vents worked fine. The problem was the rubber tube between the filler and tank. It was collapsed and plugged. Apparently it is lined with some kind of synthetic membrane, that in my case, separated from the hose and balled up inside. The rubber hose itself was deformed such that it was permanently compressed to about half its volume too. Best we can figure this is a result of ethanol. I guess at 180,000 miles, it has had about 15,000 gallons of gas pass through.

 

[2001LC]

Do you sometimes add an extra splash of fuel after the pump automaticity shuts off at fill up?

I do this all the time, is there a reason not to?

 

[paflytyer]

I do this all the time, is there a reason not to?

Overfilling can cause raw fuel to saturate the charcoal in the charcoal canister. That can lead to EVAP problems, vapor lock, or the pretty common fuel smell that 100s are sometimes known for. I've had an issue where fuel vapor would almost run out of my gas cap. Especially on hot days or up at altitude. It seems more prevalent in off highway situations where you do a lot of bouncing, jarring and off-camber stuff.

There's a few threads on here about it.

 

[2001LC]

Overfilling can cause raw fuel to saturate the charcoal in the charcoal canister. That can lead to EVAP problems, vapor lock, or the pretty common fuel smell that 100s are sometimes known for. I've had an issue where fuel vapor would almost run out of my gas cap. Especially on hot days or up at altitude. It seems more prevalent in off highway situations where you do a lot of bouncing, jarring and off-camber stuff.

There's a few threads on here about it.

Thank you for the info and to be clear: the charcoal canister is in the engine compartment isn't it?

 

[paflytyer]

Thank you for the info and to be clear: the charcoal canister is in the engine compartment isn't it?

In your truck, yes. Mine is up above where the spare tire would go, I *think* they made that change for 2003 MY's. Some of the more knowledgeable folks on here will know for sure.

 

[2001LC]

I was not aware of the change, this may be why I've rarely had gas smell. I've always top off the tank forcing the gas pump on two or three more times, getting a 1/4 gallon or so more gas in the tank.

I'm going to do a little more investigating on this subject, and will most likely stop forcing the gas pump just to be safe.

Thanks again to you and to all in ih8mud forum, it is such a great place.

 

[2000UZJ]

I was not aware of the change, this may be why I've rarely had gas smell. I've always top off the tank forcing the gas pump on two or three more times, getting a 1/4 gallon or so more gas in the tank.

I'm going to do a little more investigating on this subject, and will most likely stop forcing the gas pump just to be safe.

Thanks again to you and to all in ih8mud forum, it is such a great place.

I did not know that there is a access panel under neath the second row seats. It's where the sensors are plugged in. There is a bunch of bolts holding the top of the tank on, I had a fuel smell after a hard drive and found that a few of the bolts were not tight. It's not a sealed panel either, so fumes can seep inside easily. See pictures below. Please tilt your monitor to its side...

 

[richg]

This just happened to us on a drive from FL back to MD. Took us over an hour to fill up the truck at our first fill-up, and 45 min at our 2nd fill-up (pump was easier to modulate).

Attached are pics of the collapsed filler hose. Pretty easy to replace, just have to unbolt the two tank straps and loosen up the e-brake cable attachments near the tank to allow the tank to drop ~6".

rich

 

[richg]

So 6 months after replacing this hose, it happened to me again.

I believe that I figured out the root cause this time though. On the upper side of the 1st muffler there was a crack, allowing exhaust to leak out. I believe on the long drives this simply overheated the hose, causing the inner polyamide (nylon) liner to deform. Certain types of nylon can have a surprisingly low melting point.

I replaced my exhaust and the hose again (thankfully it is very quick to replace the hose). Added some heat barrier wrap around the new hose just in case. It's been about a month since I replaced it and have taken a few long drives since then. Knock on wood, so far so good.

rich

 

[EdsCruisin]

Very interesting Rich! Makes sense too. My heat shields had long since corroded away. I hope that works out for you.
This is why I like these forums - for thousands of lines of "stuff" you get a few gems of useful insights.

 

[4wheelforay]

In many cases fuel lines are designed to collapse in the event of a fire. I believe that excess heat is the root cause for some of the problems here.

I found this searching if I needed to replace my rusted cat heat shields.