Anybody have an idea as to why gas is backing up in my gas tank tube/line whenever I refuel?

I can fill it fine with a 5gal jug, but at the pump it backs up on me. I can put about 1-2gal's in and then it stops. Some bubbling will occur and it'll slowly go down and then it will stop all together.

Let me know what you think!

 

Does it have the clamp that props the filler neck to the bed?

 

Vent might be stopped up.

 

I'll have to check in a bit. I know the gas tube/line does go in between the frame and the bed and seems to be a bit squished, but I think that's normal for the year.

I don't remember seeing any clamps near the neck. the neck is the elbow coming from the gas door right? Metal. Because the tube from the 'neck' is rubber that goes to the tank.

 

now, if the vent line is clogged/rusted, what's an easy way of testing it without dropping the tank?

 

Pull the bed off

 

Try taking a couple of hose clamps and take the squish out of the fill hose. Worked for me.

 

Dropping the tank is very easy on these old trucks. If the gas gauge works, run it down to empty and just undo the two straps, clamp on filler neck, and unplug sender. Just carry a little gas with you if you're not sure about the gauge working right. IMO

 

I wouldn't suggest running the tank empty. Good way to suck gunk through your fuel system.

 

Unless of course you're like me and already did that once. I've since replaced the entire fuel system in my truck. I have no more gunk to suck up. (sometimes I over react)

Look and make sure fill tube has no up slope in it. Here's a little known fact. The big tube you see from the out side is actually the vent tube. The fill tube is the smaller 1" line that goes through the middle of the outer fill tube. The idea is that gas flows through the smaller hose and dumps right into the tank. The vapor then escapes through the larger hole around the fill tube. If the fill hose was cut short at some point, it will cause a back up. If this is the case, the best thing to do is either find another fill hose and replace it, or cut it out completely and fill it at half speed at the gas station.

 

First off, I'm not taking the bed off! lmao

Yeah, there's no clamp or mount for the neck. I saw in the vent tube that it has a slight 'trap' in it like a plumbing drain. I'm wondering if there's some gas in the vent at that bend.

I'll get my air compressor tomorrow and try blowing it out first and go that route.

And 77393, yeah, my FSU isn't working. I need to get a new one. I just don't want to spend the money right now. If and when I do get a new one, then I'll prob just replace all the tubing for the gas.

Oldstyle, what do you mean using hose clamps for the squish? Where the tube goes above the frame under the bed?

 

Yep, Use them to reshape the hose and take the flatness out so the fuel can flow easier without restriction. I'll try to add a pic later this morning.

I'm not discounting the suggestions above concerning the clogged vent tube. Make sure that is clear. Click to enlarge:



.

 

Very true, not sure what I was thinking on that one. I just told a guy the other day that he had sucked up all the junk off the bottom of his tank.

You're just going to have to drop it and fix it, no other way around it, unless the hose clamp, at the kink, fixes it.

 

Oldstyle, I'll try your way, since it seems the least $$.
Thanks guys, I'll keep in touch with what happens.

 

Find a filling station that will allow the truck to lean towards the passenger side as you fill it. If that lets the fuel flow in freely without backing up, then you'll know there's an issue inside the filler tube. Even with a low spot in the filler tube, the fuel should flow into the tank, since there's 2 separate hoses.