Cheapskate Fuel Tank Ideas For A 1988 Short Bed Please?

[Oyaji]

Per the title.

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Looking at getting a 1988 that is missing the fuel tank, so will also need fuel gauge sender and a fuel pump. I am not at all averse to cobbling something up.

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One thing I thought of was going with any tank that would fit between the frame rails - a good and big one, like 40-50 gallons if available. To get away with that, I would need to relocate the exhaust  pipe to the outer side the frame rail, and probably have it exit to the side somewhere ahead of the rear wheel (maybe cutting a round exit hole for the tailpipe through the lower bed valance). I'd still need clearance for the drive shaft, so  such a tank would have to be either really shallow, or be saddle-shaped on the bottom with a "notch" for  shaft clearance. I know it would be doubling my expense but if I could get them cheaply enough, dual tanks might be a desirable option. At minimum I would need stock fuel capacity.  I only know of one MJ in a junkyard around here, and it is a 4 cylinder so I know the fuel pump wouldn't work for me because the '88 has an I-6 4.0 L. 

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Please  put on your thinking caps and post up any solutions you have found or ideas you have. Thanks in advance.

[gogmorgo]

Rockauto sells stock tanks and fuel pumps, but you'll still need the sending unit. Don't know if they're interchangeable between engines/tank sizes, but unless you get extremely lucky, the only place to get one is off another MJ.

[Oyaji]

Anybody ever try  (and succeed at) making his own fuel gauge sending unit, or modding one from another application?

[neohic]

http://comancheclub.com/topic/30542-neohics-next-91-pioneer-/page-4

 

Scroll down to post #80. I've done similar setups in the past making up custom tanks that sit in the box, but I've always just measured to have the sending unit sit off the bottom of the tank at the same height that it would've in its original tank. My new adapter would make it possible to have any height/size tank, use either MJ or XJ sending units as a donor, or use an external pump and still use the factory gauge sender.

 

[Kkilmer87]

I have a fuel pump for sale if you need it came out of an 88 4.0 works fine pm me if interested

[Oyaji]

http://comancheclub.com/topic/30542-neohics-next-91-pioneer-/page-4

 

Scroll down to post #80. I've done similar setups in the past making up custom tanks that sit in the box, but I've always just measured to have the sending unit sit off the bottom of the tank at the same height that it would've in its original tank. My new adapter would make it possible to have any height/size tank, use either MJ or XJ sending units as a donor, or use an external pump and still use the factory gauge sender.

 

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Nothing... short... of... brilliant!

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I read in your post there you had thoughts of making... more than one? ;)   

[neohic]

 

http://comancheclub.com/topic/30542-neohics-next-91-pioneer-/page-4

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Nothing... short... of... brilliant!

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I read in your post there you had thoughts of making... more than one? ;)   

 

Thank you. I'll probably make up a bunch at some point. I've only ran through a full tank of fuel through it and I want to prototype it for a while before anything else.

[earl*t]

Get in line Oyaji!  Behind me. :rotf: I've been waiting to hear back from Ben. I figured his class has been busy mass producing them. :laughin:   

[neohic]

Get in line Oyaji!  Behind me. :rotf: I've been waiting to hear back from Ben. I figured his class has been busy mass producing them. :laughin:   

 

Sorry... I keep all of my "extra curricular" projects away from the school. I haven't even priced out what it would be to put one together yet. Like most things I do, the first one was thrown together with scraps I had sitting around. That, and I need to take mine apart to get some better measurements. That, and I'd like to put together a good jig.  :thumbsup:

[earl*t]

 

Get in line Oyaji!  Behind me. :rotf: I've been waiting to hear back from Ben. I figured his class has been busy mass producing them. :laughin:   

 

Sorry... I keep all of my "extra curricular" projects away from the school. I haven't even priced out what it would be to put one together yet. Like most things I do, the first one was thrown together with scraps I had sitting around. That, and I need to take mine apart to get some better measurements. That, and I'd like to put together a good jig.  :thumbsup:

:popcorn:  Ok. I'm just jerkin your chain buddy. But, I think I was first in line. :laughin:

 

 

 

40 - 50 Gallons? :eek:  Man Ojayi, that's pretty ambitious, I would expect no less. :thumbsup: GenRight offers this 30.5 XJ tank, but it's far from cheap at $899.99. Just throwing out an idea. Obviously the rear frame would need reworked. http://www.genright.com/ProductInfo.aspx?productid=GST3003#.UpaGfnco5LM

[Oyaji]

Well, when we get a hurricane down here, I can use 250 gallons per week easily, plus another couple hundred gallons of diesel... and after a storm I have a hard time getting it, too. I like to keep a couple 250 gallon tanks full down here; I usually tank up when the price on fuel drops a bit, using it when prices rise so as to rotate my stock.

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The extra tank capacity on the truck would also be useful for ferrying fuel  locally to other farms in the family when visiting/working/repairing stuff there so I don't have to tote a 55-gallon drum to get tractor and generator fuel, as well as for long trips and certain projects involving fuel economy I am working on.

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I definitely would have a use for double (or more) stock fuel capacity. Provided I can achieve it cheaply (and trouble-free) enough, I'll go for it.

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I know dual stock tanks have been done by others on their Comanches, but I don't remember the details. I guess I can come up with a solution if I think on it a bit, but if anyone here has solutions or ideas to share, I am all ears - no sense in reinventing the wheel if someone else has done the inventing already and is willing to share.   :)

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One thing I have been wondering about is why the fuel tanks for SWB are smaller than the LWB? I'm guessing there must be a clearance issue? I am really wondering if dual LWB tank mounts couldn't be   easily modified to fit if the exhaust system was re-routed outside the frame rail. Does anyone here have info/ideas to share about fitting LWB tank(s) in a SWB truck and/or about re-routing the exhaust?      

[Jeep Driver]

 

 

This one?

[Jeep Driver]

 

 

That may mount nicely at the spare tire location.......fuel neck behind a pull down tag like the old Impala........? Just a thought.

[Oyaji]

You have sharp eyes and your Google-fu is impressive: that 5-gallon bucket  with the 2 hoses going over the bed rail behind the cab is the current fuel tank.  :clapping:

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I like your Impala fuel tank idea, but I think I like the idea of keeping a spare in the stock location better... I'll have to think about that one - thanks for the idea, I just might use it.

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I asked a lot of questions, and the answers given were less than ideal:  it isn't near roadworthy so I'll have to trailer it home. As I mentioned above, that 5-gallon bucket is the current fuel tank.  It's 2wd, not 4x4.   :( It's a 5-speed, and the driver's side floor pan is gone; so is the exhaust system.  Front end is shot,  as are the tires.  Rims are 2 steel Jeep  later-model XJs (?), 2 off some sort of Ranchero. Lacks a battery too.  Unsure of the mileage, smokes a bit (valve seals? it has sat for 3 years without running).  Dunno if it has a full gauge panel with tach or not; interior is  worn, not nice but serviceable. Have not seen it nor heard it run yet, will do a compression check before final decision.

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It is absolutely more a project than I want to take on, not because I am disinterested, but rather because I am focused on a different aspect of work on a  related  truck project...  that, plus my back isn't what it was 20 years ago. But provided I can get it going well enough to benchmark certain consistent fuel economy performance targets, I think it will do well enough until I need a "show truck" as a demonstrator of my main project...

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One step at a time.     :)

[gogmorgo]

Clearance is definitely the reason the swb tanks are smaller. The LWB tank goes most of the way to the rear axle. Don't remember what stops it in the front... back of cab? tranny x-member? I'd have to crawl under and check. It's been a year since I dropped my tank.

 

If you're just looking for an extra fuel distribution tank, the exact thing you're describing goes by the name of "slip tank" up here. Lots of farmers etc run them, people who have greater fuel needs, or need to carry fuel out to equipment in the field. You can buy them commercially built, but they tend to be on the pricey side, so lots of people weld their own. Basically just a steel box that sits behind the cab. Lots of them have pump handles on them to dispense into other vehicles, and I've seen some wired to pump fuel into the truck's regular fuel tank when it drops below a certain level. I used to work at a full-serve gas station, and there was a guy who came around every month or so with an old 7.3 F350, and I had to trickle-feed 280 to 300 gallons (probably the biggest one I filled) of diesel into his home-made slip tank because he had a 90-degree elbow on on the filler neck. It's particularly memorable because he always seemed to come in during the most inclement weather... but at any rate, he once showed me how he had a fuel pump in the tank that was wired into the low-fuel light, so instead of the light coming on, it fired a relay that sent power to the fuel pump and transferred fuel into the regular tank, at least until the level was sufficient to shut off the light, at which point the pump shut off. Stupid system, but I didn't tell him that because it meant due to store policy I could no longer fill his tank with marked fuel because I was technically filling his truck...

But something like below. You can see the filler cap on the left side of the tank, and that's a pump and filler nozzle/handle on the right, for pumping into other vehicles.

[Oyaji]

Thanks, but no thanks. I really want dual tanks or a custom tank because I want to have the capacity. I also want to keep my bed free. That's why I am not keen on giving up the stock spare tire location.

 

We used to get fuel delivered here to the farm by truck - still have 3 6,000 gallon tanks plus a half-dozen or so 500s, but only use a couple 250s now that we don't do large-scale commercial farming anymore (never even used the 6,000 gallon tanks, but we still have the capacity) Somewhere out in the weeds is a 250 gallon tank mounted to a trailer - if I needed to haul fuel, I'd just put on new tires and use it.

 

I just want the long range/runtime capability for other reasons now.

[Jeep Driver]

I've been driving for 32 years and I've never had a spare tire. In the wife's Jeep......yes......but I drive work trucks and I've never toted one around.

 

 

As for the tank to tank transfer.......I'd keep things simple and use a manual switch to a transfer pump from the aux tank to the main tank, but that's just me.

 

 

The body alone is worth what he's asking for it. The bed may even be worth it.

[neohic]

 

 

Get in line Oyaji!  Behind me. :rotf: I've been waiting to hear back from Ben. I figured his class has been busy mass producing them. :laughin:   

 

Sorry... I keep all of my "extra curricular" projects away from the school. I haven't even priced out what it would be to put one together yet. Like most things I do, the first one was thrown together with scraps I had sitting around. That, and I need to take mine apart to get some better measurements. That, and I'd like to put together a good jig.  :thumbsup:

:popcorn:  Ok. I'm just jerkin your chain buddy. But, I think I was first in line. :laughin:

 

Noted.  :D

[Oyaji]

I've been driving for 32 years and I've never had a spare tire. In the wife's Jeep......yes......but I drive work trucks and I've never toted one around.

 

 

As for the tank to tank transfer.......I'd keep things simple and use a manual switch to a transfer pump from the aux tank to the main tank, but that's just me.

 

 

The body alone is worth what he's asking for it. The bed may even be worth it.

 

And after a hurricane, I've had 6 flats in one day. I carry a small air compressor and a plug kit, and sometimes get a lot of use out of it: shingles and roofing nails are everywhere after a storm and tires pick them up readily. It's best to stay home, but I have supervised debris cleanup under FEMA and local municipalities since 2005 and may end up doing it again any year. 

 

I like the transfer pump idea, it's my default solution unless someone else comes up with a better one.

 

I actually have a use for just a body, so this may sit for a while before becoming roadworthy. Thank you for your constructive ideas.

[JeepcoMJ]

tank between rails?

 

driveshaft clearance.

 

Once saw a diesel mj that had front section of bed floor cut out between frame rails and a 100-something gallon fuel tank dropped in, to clearance it for the driveshaft.

[Oyaji]

tank between rails?

 

driveshaft clearance.

 

Once saw a diesel mj that had front section of bed floor cut out between frame rails and a 100-something gallon fuel tank dropped in, to clearance it for the driveshaft.

 

Umm, yeah, I mentioned driveshaft clearance in the 6th sentence of the original post.

 

Thank you for your thoughts though.

[johnj92131]

Recall reading about a second tank for an older Toyota truck.  It had a whole in the middle of the tank for the spare tire winch to go thru and hold the spare tire below the aux tank.  Could work on a Comanche if you use a donut spare.  The 80/90's F 150 trucks had twin 19 gallon tanks and still kept the spare under the bed with a different system to hold the spare.  Especially on a short bed without that huge X brace on the long bed.  

You might want to look at the projects here that used the Dakota 22 gallon tank on the short beds also.  Don't recall reading about anyone doing dual stock tanks.  Would love to read about that!

[JeepcoMJ]

 

tank between rails?

 

driveshaft clearance.

 

Once saw a diesel mj that had front section of bed floor cut out between frame rails and a 100-something gallon fuel tank dropped in, to clearance it for the driveshaft.

 

Umm, yeah, I mentioned driveshaft clearance in the 6th sentence of the original post.

 

Thank you for your thoughts though.

 

And I confirmed your concerns, and gave you the most viable solution for a single tank setup.

A secondary tank would be best bet, as you have also noted.

 

try an XJ tank in the rear spare tire area.  would only work on a longbed, but you could get a second fuel door in it, and actually wire the xj sending unit up (if similar year to MJ) on a two position, 6 wire toggle to read on the factory gauge  The 6 wire toggle would accommodate power to pump and sender, but you would need to consider running an appropriate pressure check valve on the outgoing side of the tank pressure hose to keep from backfeeding from the primary to secondary.   Or just run a transfer pump.

 

[Oyaji]

Cogent, useful, and practical advice, thank you.

 

I'll think about it, but probably won't replace the spare with a tank for the reason I mentioned before. I'll think about using the wiring idea in whole or in part. I know dual stock tanks have been used before, and it looks like that's the direction I'll go unless I can come up with a better and cheaper custom fabrication.

 

To do that I'll need to re-route the exhaust pipe and muffler - ideas, anyone?

[JeepcoMJ]

there is not enough room to re-route any of that.   If you went with no muffler, and straight piped, maybe.   But it's been thought about, measured up, and tossed out before.

 

that spare tire spot is useless for a spare, and, unless you're not aware of it yet, you will find that the tire winches rusted out and don't work.