88 with dual tanks, help please....

[this user name may change]

in the near future i may be buying a 88 ranger that is only a single tank... i was hoping someone can give me a step-by-step on how to install dual tanks and what parts are needed to do so..... and i understand that the spare gets move to the bed but that just the cost of getting more distance between fill-ups thanks in advance....

 

[heptofite]

it's not a simple conversion at all, i have a twin tanker and it would require a lot of fab to swap it to a regular single tank truck.

 

[AllanD]

Not the least of which is the ENTIRE run of fuel lines, selector valve and complete
"Frame" wiring harness.

the only good news is that all Gen1's are wired for the selector switch...

So if you go digging behind the dash (with the instrument cluster removed) you will find the connector for the selector switch.

AD

 

[this user name may change]

so what do i need for this to work?

 

[AllanD]

short answer? a dual tank donor vehicle.

MY personal dual tank setup has evolved and whil it bears a superficial similarity to the original system (as it was when removed from the original donor)
the only "original components" of the dual tank system as produced in 1987
that remain on my truck are the selector valve (which I have modified internally)
and the wiring harness to control it.

I am running high pressure pumps in BOTH tanks and the selector valve only actually controls the flow path of the return fuel, I have physically removed the valve O-rings
on the supply side...

My rear tank is not even a ranger tank, it is the rear tank from a
1992 dually rear axle F350, because this tank is not only larger (20gal Vs 13gal) but plastic... (plastic doesn't rust!)


AD

 

[this user name may change]

ok so what your saying is that i need to find a ranger in the local junk yard that is dual tanked and use its parts and use plastic tanks?

what i dont understand is why does the selector valve only control the return?

 

[RangerSVT]

Usually when you turn the switch to the tank you want to use, it switches the tanks power to the pump on, so only the return line needs to be directed to the tank that is running, as to not "fill" the other tank..
SVT

 

[this user name may change]

could you do a step by step? or something?

 

[RangerSVT]

Really, all you need is a switch with a SPDT relay with the switch to common, and the pumps to the NC/NO slots with the selector hooked in as well...
SVT

 

[this user name may change]

wait what?
so a two way switch and.... whats the other piece?

 

[RangerSVT]

a common 5 pole relay....SPDT, single pole double throw..
SVT

 

[this user name may change]

what does that even mean?

 

[RangerSVT]

It's an electrical device designed for a wide range of uses...One of which is switching between two electrical circuits
SVT

 

[AllanD]

The presumption that all you need to do is switch tank pump power and control return fuel is in theory correct, but dead wrong in practice.

And "dead" is the operative word.

I have TWO check valves inline with the output of each tank, because I had
issues that an aircraft engineer would call "uncommanded crossfeed" where the inlet check valve built into the fuel pump failed on one occasion and the short length of hose inside the tank failed on another occasion.

In either case THE primary rule of multiple tank fuel systems is that fuel MUST return to the tank it came from, because in that tank there will be room for it... a "Crossfeed"
sends fuel to a tank that might not be empty... and infact might be full!

Understand that it takes a bit more than an hour for your fuel pump to pump the entire volume of fuel in the tank around the "loop", while in that time the engine will only burn 3-4 gallons of it... if it's crossfeeding to another full tank that remaining volume will be on the ground behind you... that unless it finds a source of ignition....

thus my "dead" comment...


Can I explain it step-by-step? sure I can... will I? Not likely... atleast not all at once....

I can't type the way I used to I suffered some nerve damage in my right arm
when I injured my shoulder this past winter and I literlally have to watch my
fingers while I type.

you need to know and deeply understand why you must not do certain things.

My goal was to maximize fuel capacity and a 20gallon plastic tank beats a metal 13gallon tank in both ways that matter.

My 1987 truck wears a plastic midship fuel tank as well... My supercab originally had a 14.5gallon metal tank midships, it has a plastic 22gallon tank now...
(that required hand made fuel lines, adding a crossmember that no 1988 or earlier has)
replacing another crossmember and modifying a third...

The rear tank REQUIRED a 1" body lift, modifying one of the deck support members in the underside of the bed and hand made crossmembers to hang it from.

I could show you in an hour or two wiuth a floor jack and a flashlight.

I can't type the way I used to I suffered some nerve damage in my right arm
when I injured my shoulder this past winter and I literlally have to watch my
fingers while I type... and my shoulder, arm and hand hurt most of the time.

AD

 

[RangerSVT]

Thanks for the info AD, and sorry to hear about your injury, hope you can heal from it
SVT