7.3 Gas Auxiliary Bed Tank Install

You and @MiTremor906 need the in-flight refueling crew badge!
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I'm going to get this decal next 😉
 
First trip in the books and this tank is everything I wanted.

484 total miles
384 miles towing ~8k lbs​
100 miles unloaded​
117 miles to empty @ 9 mpg (just shy of 1/2 tank)
0 gas station stops

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This would be a dream! I'm strongly considering this. I'm in the market for a Grand Design 311BHS (14k GVWR). I can already tell I'm going to dislike how often I need to stop for fuel with that hog.

Was there a reason why an upfitter wasn't used to run the fuel pump?
 
This would be a dream! I'm strongly considering this. I'm in the market for a Grand Design 311BHS (14k GVWR). I can already tell I'm going to dislike how often I need to stop for fuel with that hog.

Was there a reason why an upfitter wasn't used to run the fuel pump?
I didn't like the idea of forgetting that it was on and overfilling the tank.

I also like that fuel gauge isn't on 100% of the time but I can turn it on with the aux switch and not running the pump.
 
I didn't like the idea of forgetting that it was on and overfilling the tank.

I also like that fuel gauge isn't on 100% of the time but I can turn it on with the aux switch and not running the pump.
That's a good enough reason to deter me from doing that. I'd hate to have that pump just running non-stop. I've got an overly curious 5 year old daughter that likes to pretend she's in a fighter plane with those upfitters
 
That's a good enough reason to deter me from doing that. I'd hate to have that pump just running non-stop. I've got an overly curious 5 year old daughter that likes to pretend she's in a fighter plane with those upfitters
Yeah, I wanted something that was a double action to prevent accidents. Figured it would be easy to hit the wrong switch at any point. Kids, wife or guests could easily hit one as well.
 
I didn't like the idea of forgetting that it was on and overfilling the tank.

I also like that fuel gauge isn't on 100% of the time but I can turn it on with the aux switch and not running the pump.
I debated this as well. Initially thought I would use either an Upfitter or a separate switch to keep the system simple. I didn't like the overfilling aspect and have found that all I really need are shorter bursts of fuel anyway. On my last trip I only triggered the fill while at rest stops so that the DTE would update quicker. Worked out great!

I also changed my wiring plan (while I was installing it 🤷‍♂️ ) from a ignition feed to the gauge and momentary switch to a feed from my Upfitter-5 powered feed in the bed. This also is what powers the pump. This makes the gauge only on when I "arm" the entire system. I'm happy with it!
 
I debated this as well. Initially thought I would use either an Upfitter or a separate switch to keep the system simple. I didn't like the overfilling aspect and have found that all I really need are shorter bursts of fuel anyway. On my last trip I only triggered the fill while at rest stops so that the DTE would update quicker. Worked out great!

I also changed my wiring plan (while I was installing it 🤷‍♂️ ) from a ignition feed to the gauge and momentary switch to a feed from my Upfitter-5 powered feed in the bed. This also is what powers the pump. This makes the gauge only on when I "arm" the entire system. I'm happy with it!
This is good info. I may be knocking on doors at some point if I get the itch to do a project like this. I like the idea of not having to be forced to stop for fuel... especially with a trailer/5er in tow.

Awesome write up!
 
This is good info. I may be knocking on doors at some point if I get the itch to do a project like this. I like the idea of not having to be forced to stop for fuel... especially with a trailer/5er in tow.

Awesome write up!
If I recall correctly you aren't too far from me if you want to swing by and check it out at some point...
 
This is good info. I may be knocking on doors at some point if I get the itch to do a project like this. I like the idea of not having to be forced to stop for fuel... especially with a trailer/5er in tow.

Awesome write up!
Modman might be closer but you are always welcome to stop as well and look or ask questions. We both have learned a lot through this but shared most of it in a private message so we should be mostly on the same page.
 
Modman might be closer but you are always welcome to stop as well and look or ask questions. We both have learned a lot through this but shared most of it in a private message so we should be mostly on the same page.
Sounds like we need an impromptu meetup ;)
 
Sounds like we need an impromptu meetup ;)
I've missed some meetups I know that.

I'll for sure be tapping into both of your experiences if/when I get the hair up my ass to do it.
 
Great install. I've been wanting to do this myself. Like they Idea of possibly a smaller 20 to 25 gallon tank though.
I also took a gander and saw they have some alternative size tanks. I definitely could get by with 20-25 additional. I think if I could get 350-400 towing miles total it would be ideal. I don't really like to drive more than 6 hours in a day towing.
 
I also took a gander and saw they have some alternative size tanks. I definitely could get by with 20-25 additional. I think if I could get 350-400 towing miles total it would be ideal. I don't really like to drive more than 6 hours in a day towing.
My other use for the tank is having a supply of fuel for the generator. We are prone to power outages so I like the ability to have a decent amount on hand when necessary.
 
My other use for the tank is having a supply of fuel for the generator. We are prone to power outages so I like the ability to have a decent amount on hand when necessary.
This use case was on my mind the first time I saw this, plus ATV, lawnmowers, etc. I currently carry around a ton of 5 gallon jugs....

The family just decided on a camper for vacations and 7.3L fuel range has been on my mind more. How do you have this set up for filling things besides the truck? I'd be ok if I had a hose to fill the truck (plus other items) from the outside fuel fill, but assume the closed loop is needed with the primary tank?

I have the Diamondback cover for what its worth, so need to consider that in any of my plans.

Thanks for the great detail in your builds!
 
This use case was on my mind the first time I saw this, plus ATV, lawnmowers, etc. I currently carry around a ton of 5 gallon jugs....

The family just decided on a camper for vacations and 7.3L fuel range has been on my mind more. How do you have this set up for filling things besides the truck? I'd be ok if I had a hose to fill the truck (plus other items) from the outside fuel fill, but assume the closed loop is needed with the primary tank?

I have the Diamondback cover for what its worth, so need to consider that in any of my plans.

Thanks for the great detail in your builds!
I bought this to fill other items. Thing works great the few times I've used it.


They make them with a longer hose if that is all you want and use it to fill the truck as well. There are also smaller portable tanks for boats that could fit your needs as well.
 
How do you have this set up for filling things besides the truck?
Right now I'm doing it in a low tech way:

The Original Safety Siphon 6 Foot Hose For Gasoline And More - 1/2" Valve Siphon Pump - Use for Cars, Boats, Mowers - Self Priming Pump Transfers 3.5 Gallons per Minute - FDA Food Grade for Home Brews https://a.co/d/3Skel5o

The one I bought is a 10 footer... I still have thoughts about plumbing in a 2-way valve so I can fill using the tank pump, but it's low on the priority list right now.
 
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This is such a great idea and write up. Still deciding what I want to do. Have you guys had any codes thrown from the fuel system?
 
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