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Thread: 3rd gen 4runner F-150 tank swap behind rear axle

  1. #21
    heres a picture of the pump I took out. You can see the canister seperated where it snaps together. This should be what was making it stall at stop signs below 7 gallons. The angle of the pump would allow the fuel to pour right out and negate the "sump" effect it gives to the tank. This leads right into the mod I tried


    heres a pic of my ghetto mod. All I did was seal the pump up with JB water weld all the way up to the top corner( the hole for the stabilization tube is sealed inside too). I left a few holes unsealed in the top corner in case its designed to vent through that seam. This should hold the fuel level much higher in the sudo sump and lead to all things desirable while I starve the fuel pick up in the un-baffled tank. Something came up late in research though lol. Turns out traditional JB weld that people have sworn by for years now dissolves with today's fuel additives particularly in California. Its most likley not the ethanol said one chemist, but one of the additive package items added to pump gas. I have another epoxy holding my purge fitting on the tank that has been fine for years but this use is alot more exposes no to mention sloshing fuel will contact it. I'm adding a jb water weld chunk to a jar of gas to watch for break down.
    Last edited by troyboy162; 02-14-2014 at 10:56 AM.

  2. #22
    Tank vent solved with expensive fittings... But there is no possible way to put the vent under water now. I also deleted the charcoal canister and will try free venting for awhile. The change back to a smog legal system takes 5 minutes.


  3. #23
    hmmm today I burned 19.6 gallons out of my 18 gallon tank and I didnt even run out of gas. Ive read some people call it a 22 gallon tank and that may be more correct seeing as I took way more then 18 out when I drained it as well.
    The fuel pump mod is working i'd say!

  4. #24
    Good news!

    Just curious, and don't want to surf through the thread, did you remove the rear cross member? And if so, what did you replace it with? I'm thinking about cutting mine out and replacing it with something higher up.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  5. #25
    I have the spare tire cross member removed and the front stock gas tank cross member cut out. But I have a sorta cross member in my transfer skid and two extra ones in my rear bumper.

  6. #26
    update on the water weld:
    zero deterioration after two months in a jar on my kitchen counter. Thats with 87 octane cali gas. The small details such as my fingerprints are as sharp as the day I made them. The test is over since I'm tired of a having a jar of gas in my kitchen lol.

  7. #27
    HAHA!

    I used some of the quik steel or whatever stuff to fix a hole in an evaporative cooler, hopefully we will get one more year out of it. It is holding so far.
    2005 Lexus LX470 - Stock for now...

    1998 Toyota 4Runner SR5 V6 4x4 + a bunch of goodies. Lifted, Locked, Illuminated and Armored. Winner,"Best Offroad Truck" - 2010 Pismo Jamboree. It's been upside down and still drives me to work.

  8. #28
    Quote Originally Posted by troyboy162 View Post
    update on the water weld:
    zero deterioration after two months in a jar on my kitchen counter. Thats with 87 octane cali gas. The small details such as my fingerprints are as sharp as the day I made them. The test is over since I'm tired of a having a jar of gas in my kitchen lol.
    :Like:

  9. #29
    my thoughts when I first made this were that the truck would not be A) driven fast or B) jumped. Well those two things are not true anymore so I needed to contain the fuel tank from the top as well. I found a really easy solution that looks like it will work great.

    This is nothing more then metal strap over top of the cradle I made. The strap is thin enough to conform to the tank when cranked down and mates it solidly to the cradle. There no more possibility of the tank moving. While making this upgrade I saw the tank had already slightly moved from the spot where it had been for years.

    and the picturres are a little poor but I think it shows how it all works.

    This is where the strap is tightened. That is either a grade 5 or 3 long bolt. I had forgotten how soft they are, but it works for this. The picture dosnt show it very well but the strap is running along the bottom support. The bottom support curls upward over the edge of the tank so that the strap only pulls down and not rearward on the tank


    heres the strap coming down to the rear of the truck. Its just tied in at the rear mount bolts.
    Last edited by troyboy162; 01-02-2015 at 04:51 PM.

  10. #30
    Alright...I just had two more fuel pumps die. One that lasted a year and the replacement that lasted three weeks. That means the fancy venting modifications I did were not helpful and the possibility of faulty pumps is now near zero. Its probably something dumb like low voltage to the pump causing overheating...Fun times. This last pump did not get weak slowly. It went from fine to maxed short term fuel trims instantly.

    I have researched like crazy on the subject trying to find some smoking gun to why these ford pumps will not work for me. There is no reason it shouldn't. Ive even learned that the toyota tank does not have a pressure sensor in it as I once though. That means the evap system can even work properly and, when hooked back up, did so that I could pass smog. Differences in PSI and flow are handled by the fuel pressure regulator. You can mount a slew of pumps behind that regulator without issue The FPR and ECU would make sure everything is fine. The only differences in this system are the sumps. Ford has a module and Toyota has baffling built into the tank.

    Part of me wants to move to external fuel pumps, but they are known to fail more often do to the elements and increased heat without a bath of fuel to cool it. External pumps really only offer ease of replacement/install while suffering in every other category.

    More fun to come soon haha.

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