[jdwarren]

The wife and I are planning a road trip in the near future and I knew the 36 gallon on-board tank was going to impede progress while pulling our trailer and trying to make good time, so I went ahead and purchased the 50-gallon Titan Travel Trekker on Amazon. The instructions are very generic so I was on my own in terms of mounting the pump, switch, wiring, and plumbing. I think my total install time was about 10-12 hours, a good bit of which was just figuring out how to do things, rather than actually doing them. Hopefully this write-up saves some folks some time (shout out to @hdrolling).

Note: please read the factory instructions and my complete write-up in their entirety before beginning installation. And be aware that while I like to think that I know what I'm doing, any deviations from the factory's instructions are your responsibility alone.

Note that the tank install instructions are designed for an essentially "permanent" installation. I wanted modularity so I did some things that may not be optimal if you have no intention of removing the tank on any sort of regular basis. In particular, I used quick disconnect fuel and electrical fittings (purchased separately from the tank). Additionally, I deviated from the install instructions by not drilling holes in the bed for the fuel and electrical lines, since our beds have capped holes in the upper part of the bed that can be used instead. I also deviated from the instructions by not grounding the tank to the brackets; more on that later.

Stuff I used in addition to the hardware provided:

Wire loom: https://www.amazon.com/gp/product/B07DW17QJZ/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
3/8" fuel hose: https://www.amazon.com/gp/product/B0058I2552/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
5/16" fuel hose: https://www.amazon.com/gp/product/B008VO5YP8/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Hose clamps: https://www.amazon.com/gp/product/B001HWGMBG/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
12V all-weather quick connectors: https://www.amazon.com/gp/product/B01A6LTK44/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1
6AN Male Flare to 5/16 Hose Barb Fitting: https://www.amazon.com/gp/product/B07DXP22NT/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
6AN Male Flare to 3/8 Hose Barb Fitting: https://www.amazon.com/gp/product/B07DXP4JMR/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
6AN Female Flare to 5/16 Hose Barb Fitting: https://www.amazon.com/gp/product/B07CYY92KG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
6AN Female Flare to 3/8 Hose Barb Fitting: https://www.amazon.com/gp/product/B07DLQGYQP/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
WD-40 silicone spray: https://www.amazon.com/WD-40-Specia...911&sr=8-1-spons&keywords=wd40+silicone&psc=1

You'll also need a 10A fuse and holder, as well as additional butt connectors and ring terminals of various sizes. You will also want a set of truck ramps to make the wiring and plumbing easier. I use these and they are fine: https://www.amazon.com/gp/product/B0117EETEK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

The first step is to haul the tank up into the bed and situate it. It should fit easily under any bed cover. The instructions say to center it but I offset it to the driver side for two reasons. The first is that it makes the fill neck closer to the bed rail, which facilitates filling. The second is that I wanted the brackets to be set such that the heads of the upward-facing carriage bolts would be in the recessed grooves in the bed. I recommend that you attach the fuel lines to the barbed fittings on the fuel intake and return lines so you can figure out how much clearance you need off the front of the bed. You have a good amount of freedom in how far you offset from the front of the bed to accommodate different style bed covers and other accessories that may cause interference.

In my short bed truck, I set the tank such that the seam down the middle was exactly 9" from the front of the bed (that's from the lip along the top that sticks about an inch or two out from the lower part of the front of the bed). I believe it says to use a 7/16" bit, but I think I used a 3/8" and it was fine. However, installation hardware may vary somewhat based on purchase date.

With the tank set in the bed where you want it, go ahead and mark the holes for the brackets. Some may find this unsightly, but I just outlined the edge of the brackets with a black sharpie. Now you can easily mark your holes.

Next, remove the small heat shield from the passenger side of the underside of the bed.

This part is important: You will be drilling directly over the fuel tank (and fill tube) and you do not want to risk going through the top of it. To that end, I recommend the following precautions: 1) use a backstop (a block of wood, for instance) placed between the on-board tank and the bed to block the drill bit when it punches through, and 2) use a 4x4 or something as an additional backstop for the drill itself to limit how far it can go through the bed.

I recommend you seal the bare metal edges with paint or caulk (I used black silicone) to prevent corrosion. Here's what it looked like when I finished the brackets.

Now go ahead and reinstall the heat shield you removed earlier. You shouldn't need to work in this area again.

I mentioned above that I deviated from the install instructions by not grounding the tank to the brackets. There are two reasons for this. The first is that if you do this correctly, the brackets themselves should not be grounded , or at best, have only a weak ground. This is because there will be some barrier between the carriage bolts and the bare metal (the paint or silicone I used); these are not sheet-metal screws that have a direct interface with the metal. The second is that I wanted the tank to be modular. I wound up just bonding the two ground wires (the one on the fitting that is supposed to be grounded to the bracket and the one on the sending unit) together and connecting them to a 12V quick connect; more on that later.

The next thing I recommend you do is to run the fuel lines from the tank to the tentative pump location. I recommend that you install the fuel quick-connects (if you bought them) at this time as well, so you'll be working with the actual length of available hose. However, before you put on the quick-connects, push the grommets onto the hoses so once everything is plumbed you can seat (and optionally, caulk) the grommets without any disassembly or drama. When you install the quick-connects, I recommend you reverse the gendering on the fuel and return lines so that when you remove the tank you can completely seal both the tank and your truck's fuel system (see second pic below). For instance, the truck side of the fuel line should be male, while the truck side of the vent line is female. This also prevents you from mixing up the fuel and vent lines during tank installation.

Truck and tank sealed/isolated and prepared for the tank to be removed:

Grommets and loom plumbed through the hole on the upper driver side hole in the front of the bed (with black silicone to prevent them from slipping):

Now, to mount/plumb the pump. The best place I found for the pump was a pre-existing bolt in the bed that you can easily remove and then run the bolt through one of the holes in the pump's mounting bracket. You may have to drill this bracket out very slightly for it to fit, but it's otherwise a great place for mounting (I only secured one side of the pump; with a bolt this size holding it, I think it's fine). You can also use a large ring terminal on the grounding wire to ground the pump to this bolt.

If you're smart and ran the loom through the hole like I mentioned above, you'll run a grounding wire for the tank down through the loom to this same bolt and ground it there as well. That will allow you to completely avoid drilling grounding screws into your bed (in my pictures you'll see an unsightly grounding screw near where I ran the fuel lines and loom through the hole; didn't think of this until after the fact).

The image below shows my configuration and it works fine. However, I recommend that you try to install the double-Y barbed fitting into the vent line at a location where the vent line is more steeply inclined because it will prevent a "fuel trap." Because the vent line is relatively flat where I installed the fitting, the fuel spraying into the fitting from the pump actually blocks the vent line to some extent, which forces the pump to fight the static pressure of the fuel associated with its height above the on-board tank. The effect is extremely minor and is only perceptible when you open the on-board fuel cap immediately after (or during) auxiliary pump operation, or try to add fuel to the on-board tank immediately after running the auxiliary pump. It's not nearly significant enough for me to re-do the installation to avoid it, but if I was doing it again from scratch and could do something to minimize it, I would. What you absolutely do not want is for the fuel line from the auxiliary pump to be higher than the vent line back to the auxiliary tank. That will cause all sorts of issues.

Here is the section I cut out of the truck's vent line:

Next step is the wiring. Following @1Blue78's advice, I tied into the "retained accessory power" by crimping a female flat blade connector (14 ga, I believe) onto the power wire for the control unit. I fused the connection with a 10A fuse and grounded it using one of the dashboard bolts, as shown below.

You can mount the control unit here with the provided velcro tape. You can see in the picture below how I ran the blue and purple wires through one of the holes.

Now comes the annoying part: getting the wires out of the cab. Again following 1Blue78's advice, I ran them through the grommet used to pass the parking brake cable through the floor. But first, I cut the tips of the wires diagonally to make them pointier, which helps in ramming them through the rubber boot/grommet.

You will need to remove the trim pieces around the floor (including, possibly, the door sill plate -- try not to crack it like I did) in order to access it. It is held in by two bolts; remove them. Spray the parking brake cable and the tips of the wires with silicone, then pull the grommet back up the cable a bit. Now stick the wires into the top of the grommet and ram them through. You may want to just hold them against the cable and slide the grommet up until you can grab them on the other side.

Now go under the truck with your loom and ram the end of it up through the hole through which the parking brake cable passes. Zip-tie the loom to the parking brake cable and pass the wires through the loom out of the cab.

Re-seat the grommet and reinstall the bolts, carpet, and trim. Secure the wires out of the way, optionally covering them with loom (I didn't but it can't hurt).

The rest is easy. Route the wires along the frame rail back to the pump. Conveniently, there were some plastic hangers already installed that I was able to use to hold my loom/wires which gives it a very OEM appearance.

Make sure you route your wires behind the cab-frame mounts, otherwise you'll feel dumb like I did and have to re-do it. Here's what you don't want:

I just hit the image limit. I will continue the write-up in the next post. If you happen to be seeing this before I've posted the rest of it, please do not reply until the entire write-up is posted; this will help continuity. Thanks.

 

[jdwarren]

And here's what you do want:

At some point, you'll have to split your blue (pump) and purple (sending unit / level meter) wires apart into two separate pieces of loom. Cover all gaps in the loom with electrical tape.

Connect the blue wire to the pump using a heat-shrink butt connector (and make sure you heat-shrink them). Cover the wire with loom and secure it out of the way.

The completed wiring along the frame rail should look something like this. Note my use of zip-ties after the cable hangers had stopped.

Now go back up into the bed and run a piece of purple wire down through the loom that you already ran through the hole in the bed. Connect the female side of one of the 12V quick-connects to this wire along with the grounding wire that runs to the bolt where the pump is mounted (this grounding wire is instead shown grounded to the truck bed in my picture; you can avoid this ugliness by following my instructions above for re-using the ground at the pump for the sending unit as well). [See "update" below; I went back and actually rewired the sending unit this way.] Connect the other end of the wire to the purple wire that came from the control unit in the cab using a heat shrink butt connector. Cover all wires with loom, and any gaps in the loom with electrical tape.

Now bond the grounds from the tank fitting and the level meter together, and connect this consolidated ground as well as the +12V side of the level meter to a male 12V quick connector.

And that's about it, folks. Secure the tank with the brackets according to the instructions, connect the fuel and electrical quick-connects, and you're all set. Good luck and let me know if you have any questions.

Update: I got so annoyed at the thought that I could have re-used the ground at the pump for the sending unit as well that this morning I went out and implemented this design. Here are some pics.

 

[hdrolling]

This is going to come in handy, thank you!

 

[jdwarren]

This is going to come in handy, thank you!

No problem. I got so pissed last night when I realized how I could/should have wired the ground for the sending unit that this morning I got up and actually did it. I edited the second post to show how it looks now.

 

[hdrolling]

No problem. I got so pissed last night when I realized how I could/should have wired the ground for the sending unit that this morning I got up and actually did it. I edited the second post to show how it looks now.

You did a great job and a great write up, I'm going to tackle rear air bags first but this should be happening in a few months.

 

[jdwarren]

You did a great job and a great write up, I'm going to tackle rear air bags first but this should be happening in a few months.

Sounds good. Post a write-up for your airbags if/when you have the time. I just discovered that the floor is rotting in one of the slideouts of our TT (and unfortunately it's the one with the stove, fridge, etc.) so I think this road trip may be its last hurrah before we upgrade to a fifth wheel. I'll probably need air bags (and possibly 19.5s with 16-ply tires) to handle the pin weight since we will likely go for a large toy hauler.

 

[hdrolling]

Sounds good. Post a write-up for your airbags if/when you have the time. I just discovered that the floor is rotting in one of the slideouts of our TT (and unfortunately it's the one with the stove, fridge, etc.) so I think this road trip may be its last hurrah before we upgrade to a fifth wheel. I'll probably need air bags (and possibly 19.5s with 16-ply tires) to handle the pin weight since we will likely go for a large toy hauler.

There is always something with these campers, I never knew how much of a money pit it was going to be. But the kids love it and ask to go camping all the time so I just keep repairing.

The toy haulers are nice, lots of extra sleeping space.

 

[86burgandyss]

Great write up! I have a 17 that I installed my dually depot 115 gallon auxiliary tank that I had in my 07. The auto fill module had gone bad, but still gave me my fuel level, so I'm still using that for the gauge part. I bought the killer neck piece for the 17 and just wired in a stand alone switch. Will post a picture later.

 

[touchracing]

This is an excellent write up. My 50-gallon Titan Travel Trekker was delivered this week. Hope to start the install this weekend.

 

[blythkd1]

@jdwarren, what pump did you use? Maybe I missed it. And do you like the pump? How fast is it? Would you do anything different? Thanks,

 

[jdwarren]

@jdwarren, what pump did you use? Maybe I missed it. And do you like the pump? How fast is it? Would you do anything different? Thanks,

I used the pump that came with the kit. It worked but was very slow. Recently it totally died on me and I replaced it with one of these which seems to work much better. I also replaced the crimped connections with a waterproof 12v quick disconnect so if this one shits itself too I can replace it again quickly.

After replacing the pump I realized that the original one was likely sucking air which explains both its poor performance and early demise. I say that because I remember when I first installed it and ran the pump for a few minutes I'd hear air coming out of the main tank when I removed the fuel cap. There's and air return line to the auxiliary tank so the only way the pressure would increase is if air was being pulled in from the outside.

Other than that everything has been great. I definitely recommend the quick disconnect fittings on the hoses like I did, although maybe there are better ones that don't require any wrenches. Don't forget to disconnect the fuel hose from the top of the tank if you have to replace the filter or pump if your filter and pump are under the truck, because if you don't it'll siphon diesel directly into your face at a high volume flow rate (don't ask how I know).

 

[blythkd1]

Thanks, very good feedback.

I'll have to have a manual shutoff valve directly out of my auxiliary tank to be DOT legal. So if I shut it off and have to disconnect anything under the truck, I shouldn't get very much fuel in the face

 

[jdwarren]

Thanks, very good feedback.

I'll have to have a manual shutoff valve directly out of my auxiliary tank to be DOT legal. So if I shut it off and have to disconnect anything under the truck, I shouldn't get very much fuel in the face

That's a good idea regardless. If you have a shutoff valve and don't foresee removing the tank for more bed space then the quick disconnects really aren't essential. I thought I'd pull the tank out when not using it but it's been in there for over three years now.

FYI, the fuel supply line that comes with the kit is 3/8" ID. For some stupid reason the manufacturers of these little fuel pumps don't think that the fitting sizes are particularly important and so their sizes typically aren't listed on the packaging or online product listing (look at the link I sent from Pep Boys for example). I find that utterly baffling, but in any case, just make sure that what you get has a 3/8" barb fitting. The pump I purchased actually wound up having a 5/16" fitting but I was desperate for immediate gratification so I just wrapped a whole bunch of yellow Teflon tape around the fitting and rammed it into the fuel line and cinched it down with a hose clamp. The outlet into the main fuel neck is just a few inches downstream of this point so the gauge pressure there is probably only 1 or 2 psi; hasn't leaked yet and I'm not worried.

That said, I will probably put together (and keep in my trailer) a drop-in replacement pump and filter that's already set up to be bolted, plumbed, and wired in place so if I'm on the road and the pump fails it's 20 minutes of easy work rather than hours of detouring to find an auto parts store and rigging stuff up. The spot under the bed where I installed the pump is pretty tight so if you use a pump with a bolt pattern different from what you install the first time you'll probably spend some time just figuring out how to mount the thing, and then you'll realize that your hoses aren't long enough if you orient the pump differently, and the store you got your new pump from doesn't have any 3/8" hose unions, and the store you get the unions from doesn't have fuel line, and next thing you know half a day (or more) is shot trying to patch together $30 - $50 worth of crap.

 

[blythkd1]

The spare pump probably isn't a bad idea if you routinely travel very far from home, especially given the relatively cheap cost. I carry more dollars worth of fuel filters under my back seat.

In the event of a pump failure, will fuel not gravity feed through the pump? Most of the guys I know with auxiliary fuel tanks just use gravity feed anyway. I've always ran a pump and don't know if I have the patience for gravity feed, not to mention if you forget to shut the auxiliary valve off with fuel in the tank and remove the main filler cap, you get a bath.

 

[jdwarren]

The spare pump probably isn't a bad idea if you routinely travel very far from home, especially given the relatively cheap cost. I carry more dollars worth of fuel filters under my back seat.

In the event of a pump failure, will fuel not gravity feed through the pump? Most of the guys I know with auxiliary fuel tanks just use gravity feed anyway. I've always ran a pump and don't know if I have the patience for gravity feed, not to mention if you forget to shut the auxiliary valve off with fuel in the tank and remove the main filler cap, you get a bath.

It will not gravity feed and unless you deliberately wire/plumb it to support that, you don't want it to. In my install there is no valve to stop the flow of fuel so if it were to free-flow through the pump it would flow until the entire main tank was full, and by "full," I mean fuel all the way up the fill neck such that if you opened the main fuel cap it would start pouring out (if the auxiliary tank was full, due to the fact that the fuel level of the aux tank is higher than the fill cap on the main tank).

On the Titan tank the fuel pickup is actually at the top of the tank with a tube that descends down to the bottom of it, so to gravity feed it would need to be primed anyway. If you want to gravity feed you should look at tanks that have an outlet fitting at the bottom of the tank.

 

[jdwarren]

The spare pump probably isn't a bad idea if you routinely travel very far from home, especially given the relatively cheap cost. I carry more dollars worth of fuel filters under my back seat.

In the event of a pump failure, will fuel not gravity feed through the pump? Most of the guys I know with auxiliary fuel tanks just use gravity feed anyway. I've always ran a pump and don't know if I have the patience for gravity feed, not to mention if you forget to shut the auxiliary valve off with fuel in the tank and remove the main filler cap, you get a bath.

Additionally, I agree that gravity feed will be very slow, and for it to be convenient it will be at least as complicated as a pump-based system because you'll want a solenoid-actuated valve and the circuit to the solenoid should have a time-delay switch or something so that it only opens the valve for a set period of time. And if the solenoid fails or the valve sticks, well...now you have the same unlimited flow mess. If a pump fails you just shrug and swap it, it's not going to result in a call to the DEP, thought police, or anyone else.

On that note, the fuel flow rate from a gravity based system will exhibit a significant dependence on the level of fuel in the auxiliary tank because the pressure head at the valve will be a linear function of the depth of fuel in the tank. I know you have a math degree so a glance at the Bernoulli equation and the formula for hydrostatic pressure should make this clear if it wasn't apparent already. Bottom line is that at low levels of fuel in the auxiliary tank the flow rate will be very slow.

 

[blythkd1]

Absolutely correct about the flow. And on a cold day with a fuel filter that's even slightly fouled, you may not get much flow at all. I've been running a large transfer pump with 3/4" hose and manual nozzle. I pull over, turn the pump on, put the nozzle in my tank filler just as I would at the station pump, then run 25-30 gallons in about 3 minutes. I've seen bitter cold days where even my high capacity pump took forever to fill my tank.

I've thought many times about hard lining a remote switched pump into my system but since I'm really bad about driving for hours without stopping, I've always figured the necessity to stop and transfer fuel wasn't necessarily a bad thing. When I'm hooked up towing, I usually have to stop about every 4 hours or so to fuel up. It's a good time to stretch my legs, cool down a hot tire, check to make sure nothing is trying to fly off the trailer, etc. But on this truck I'm really considering the hard lined pump. If for no other reason then just to ensure fewer contaminants get introduced into the fuel system. My filler nozzle can get a little grimy.

I have a 100 gallon tank ready to go. It has 2 bung holes on top as well as a 1/2" fitting on the bottom. I may hook it upgravity feed initially and see how it goes. I'll be in a pinch for time to get it installed and going. It wouldn't be hard at all to add a pump later. I'm very familiar with the wet leg filler issue. Many other camper toters have taken the diesel fuel bath and shared their stories. If you forget to shut the valve off and still have fuel in the aux tank, don't remove the filler cap until you've burned some fuel. The solenoid valve with a timer is a good idea. Even if it was for only 10 or 15 minutes, you could just trip it multiple times to fill up much like I've had to do with my rear window defogger from time to time. That would beat overfilling the tank.

 

[jdwarren]

Absolutely correct about the flow. And on a cold day with a fuel filter that's even slightly fouled, you may not get much flow at all. I've been running a large transfer pump with 3/4" hose and manual nozzle. I pull over, turn the pump on, put the nozzle in my tank filler just as I would at the station pump, then run 25-30 gallons in about 3 minutes. I've seen bitter cold days where even my high capacity pump took forever to fill my tank.

I've thought many times about hard lining a remote switched pump into my system but since I'm really bad about driving for hours without stopping, I've always figured the necessity to stop and transfer fuel wasn't necessarily a bad thing. When I'm hooked up towing, I usually have to stop about every 4 hours or so to fuel up. It's a good time to stretch my legs, cool down a hot tire, check to make sure nothing is trying to fly off the trailer, etc. But on this truck I'm really considering the hard lined pump. If for no other reason then just to ensure fewer contaminants get introduced into the fuel system. My filler nozzle can get a little grimy.

I have a 100 gallon tank ready to go. It has 2 bung holes on top as well as a 1/2" fitting on the bottom. I may hook it upgravity feed initially and see how it goes. I'll be in a pinch for time to get it installed and going. It wouldn't be hard at all to add a pump later. I'm very familiar with the wet leg filler issue. Many other camper toters have taken the diesel fuel bath and shared their stories. If you forget to shut the valve off and still have fuel in the aux tank, don't remove the filler cap until you've burned some fuel. The solenoid valve with a timer is a good idea. Even if it was for only 10 or 15 minutes, you could just trip it multiple times to fill up much like I've had to do with my rear window defogger from time to time. That would beat overfilling the tank.

Sounds good. If you want to be able to convert between gravity and pump-based easily all you would need to do (I'm sure this is pretty obvious to you but it can't hurt to mention it; never know who'll read this in the future) is have a long enough loop of fuel line that you can run it up from the bottom fitting up above a point higher than the highest fuel level in the tank and secure it in that position. That will prevent the limitless flow problem (assuming the line isn't primed).

 

[jdwarren]

@blythkd1 okay, it turns out I'm dumb. This new pump definitely allows flow-through and therefore once it begins pumping the siphoning continues without bound. I think there's some kind of pressure release valve at the top of the main fuel tank because if the aux pump is primed and the main tank is full it leaks, and it appears it's coming off the top of the tank and dripping down (the leak doesn't look like it's coming from the aux tank plumbing). I opened the quick disconnect to break the vacuum and stop the siphoning. I'm going to see if a simple marine anti-siphoning valve can eliminate this nonsense. I'll report back when I've got the results.

 

[blythkd1]

I hooked mine up gravity feed initially and see how it goes. I can always add an inline pump at any time if I so desire.

At first blush, the gravity seems to work well, I'm just concerned how well it will work when it gets colder and the fuel isn't as thin.