For anyone that fills their tank to the top, harpooning is worth the trouble. I was going to lift my bed to get to the tank, but the bolts wouldn't budge after only one winter... I ended up dropping the tank which is easy even w/ the skid plates. I used a motorcycle jack to lower the tank and it worked great. Like everyone has said, putting the plastic nut back on the pick up is the hardest part. After I filled up it did leak a little, but it turned out to be only the vent line. I just had to drop my spare tire and tighten the worm clamp a little more. My first fill up clicked off w/ less than .8 gallons left to go. It used to be 4 gallons to go like clock work. I figure 4 gallons times 16 miles per gallon means I can go another 64 miles before I have to fill up. Less time at the gas station and fewer times going is good to go in my book. I think the plastic hose cutter would have made it easier, but a good razor knife works just fine.
Also, for anyone scared of check engine lights due to filling up to the filler cap, it hasn't happened to me yet after doing it for 26k miles...

 

Never happened to me either. Thanks for the post.

 

Agree it was the best mod yet . (if you can call it a mod)

I all so found if you put the plastic ring in hot water before installing it goes on real easy.

 

what is harpooning? Ive never heard of it.

 

Got this on my to do list....

 

Agree, best mod yet. I hate standing by the side of the truck dribbling in fuel when it is freezing outside. Now it shuts off with less then 1/2 gallon until the top of the filler tube. Much, MUCH faster when filling up. Wish I would've done it sooner. (I also wish I would have known the plastic ring was going to be so tough. I thought I was just stupid as it wouldn't screw back on for a while.)

 

Does this but me anything if I fill up at a truck stop? I've heard of it and read some about it, but I can fill up in about 30 seconds. The truck pumps put it in so fast all I do is hold on. If you're talking about another gallon, is it really worth it? It looks like I get it pretty near the top now.

 

Like I said Chili7, mine would shut off with 4 gallons to go. I think if it were a gallon I wouldn't do it, but it's worth it for the quick last four gallons. I've read about the hot water trick, but I didn't feel like heating up the water, so I wasted fifteen minutes fighting with it to get it back on...
mrwake, this is a process of dropping the tank and cutting off a few inches of the vent and filler tube. It makes it so the fuel doesn't cause the pump to shut off so soon. If you go to your search engine and type in "harpoon 6.0" you'll probably come up with this site and the string. I get 32-33 gallons in a 29 gallon tank and I can accurately check my mileage. It's the best gauge in my book to see if anything negative is going on in your motor. If someone else happens to have the link to the string, please post it so they can see what we're talking about. I hope the search comes back soon!

 

I agree, have done 4 fill ups since doing this and it takes more fuel as well as goes faster, although that depends on the stations pumps settings too.

 

At the top of the 6.0 PSD forum (go back one page from here) you will find the Tech folder. About half way down is the link to "How to Harpoon the fuel tank". There are many good tech articles in that folder. Here's the link to Harpooning the tank...

https://www.ford-trucks.com/forums/259149-harpoon-the-tank.html

I tried this link and it didn't work for me, not sure why. Just go to the tech folder at the top of this forum and look for it there if it doesn't work for you....

 

Sounds like a good mod. How does this affect (if at all) the onboard computer for things like miles-to-empty, etc. Does it just perform the calc based on the sensors in the tank? I hand calc mileage, so no biggie there, but there have been a couple of times I *really* needed to know how many miles I had left to empty. (And I do know it's not good to run out of fuel, so I hope I never need to 'fess up....)

 

Correct. All the original equipment is still in the tank so it relearns the volume I am gussing after additional tankfuls have been run thru.

 

Harpooning. Sounds like a whale of a thing to do. Wonder if it will work on wifes brand X?

 

Do the vent lines cause the same problem on bigger aftermarket tanks like the 55 gal. from Transfer Flow?

If so, can you "harpoon" them also?

 

DO IT! Filled up the other day 39.7 gallons held maybe a gallon or so after it kicked off.