View Full Version : Auxillary fuel tank set up
11-02-2005, 07:10 PM
I am looking to install a 2nd hand 60l sub fuel tank (ex nissan duel fuel) in my nissan safari. It is a 4.2l diesel.
What is the best/easiest way to set it up?
With the filler do I just cut a tee piece into the existing fuel tank filler hose.
Where is the fuel pump? How do I connect the fuel lines? What about a fuel gauge? can i install a flick switch and use the existing gauge to tell what is in each tank or will i need a seperate gauge? Would it be easier just to use a pump to transfer fuel from the sub tank to the main tank when it gets down towards empty?
I am open to suggestions.
12-02-2005, 04:15 AM
I would have a separate filler for the Aux tank and put in an electric pump so that you can pump from the Aux tank into the main. Put in a guage so that you get an idea of how much is in the auxilliary tank. Does the tank have a sender unit on it?
If so shouldnt be too much of a drama. ;)
12-02-2005, 04:36 AM
That is one idea i had. would the filter go before of after the pump.
Do i just install a tee into the filler pipe so that when the main tank fills it overflows into the aux tank?
Yes the tank has a sender unit.
17-02-2005, 03:31 PM
i own a pajero that used to run on gas! they remove the original tank and put the gas tank in its place and add a auxillary tank! anyway when i bought it the gas was removed , so i was running off the auxillary tank! i bought a original tank from the wreckers and am at the same place you are with what to do! i have considered using a solenoid that can be switched from the cab to change siphon from main tank to auxillary! but they cost around $200 ! also the filler pipe i had to consider! i was going to make a 'Y' piece in the main filler pipe so i could fill each tank but i opted for seperate pipes! but anyway what i am going to do is place a electric fuel pump to pump from auxillary tank to main! alot easier! also the auxillary tank already had a sender so i will go to autobarn and get a guage!
18-02-2005, 02:21 PM
Sounds very similar to what I am going to run with however I'm just going to use the one filler pipe. My only concern is what would stop you from accidentally activateing the transfer pump when the main tank is fuel.
Potentially be sitting in a a big puddle of fuel.
19-02-2005, 04:41 AM
If you transfer from one tank to another you also can have the problem of pumping the tank dry, or accidently running the pump until the tank is dry and stuffing the pump.
An easy way to use fuel from one tank or the other is to put in 2 electric pumps. One pump from each tank and have a switch in the cab(single pole, double throw available from any Dick Smith etc.)so only the appropiate tank pump can work (no accidents)
I'd also put 3 filters in. One on the line from each tank and one before the carby.. (filters are cheap, repairs aren't :-[)
Hope this may help
19-02-2005, 04:44 AM
If you use the above set up you can also use a 2 pole, double throw switch to work the existing fuel gauge from either tank ;)
Two fillers is better then one..
If you want send me an e-mail and I can give you a diagram for the electrics ;)
19-02-2005, 07:59 AM
So that you do not overfill the main tank you can run a line from the side (at the top) of the main fuel tank to the auxilliary tank. This way as soon as it is almost full it overflows back into the auxilliary tank.
As far as the empty tank goes, you can set up a relay circuit so that when the sender unit on the auxilliary tank reaches a certain point it cuts the power to the electric fuel transfer pump.
19-02-2005, 09:35 PM
If you think about it if i was to use the one filler pipe with a y piece cut ito the filler pipe the main tank would fill and overflow into the aux tank. If the transfer pump was activated and the main tank could not hiold the capacity of the aux tank it would overflow up the filler pipe and back to the aux tank.
With seperate filler pipes you would need the over flow system as you describe.
I am not sure how to wire up the relay system as you describe.
19-02-2005, 09:40 PM
Running off the aux tank only you must be getting to know the cashier at the local service station very well.
19-02-2005, 09:50 PM
I am not sure where the fuel pump in my vehicle is. Some vehicles have them in the tank and othes at the engine end.
What happens if a diesel runs out of fuel? I have heard that the fuel system requires bleeding. Is this the case? How is this done?
If the fuel pump is at the engine end i could us a couple of solenoids and switch from one tank to the other instead of a fuel transfer system.
Similar with the fuel sender i use the existing in dash fuel gauge I could flick a switch to see how much fuel was in either tank.
How do the toyo and later nissan set up ther fuel systems?
Might just get a jerry can.
21-02-2005, 09:07 AM
You'll have to look for the fuel pump because who knows where it could be.
The easiest way to see if it is in the tank is to listen for the ticking noise of the pump.
Yes you are right about the running out of fuel. The system will have to be bled and it should tell you how to do it in your manual. Usually it is onlya matter of loosening a few bleed valves and letting the air out. :-/
And again you are correct, if the pump is at the motor all you need is 2 solenoids and a 2 pole/double throw switch so you can switch both the solenoid and the fuel gauges sender units at the same time. The only thing you'll hav the watch when you use the one gauge for two tanks is if the two sender units are compatable.
If there is some fuel in both tanks all the time you shouldn't have to bleed the system. :D
Jerry cans are good if you want to always find room for them and want to tie them up and then want to spend time syphoning fuel from one to another and just hope you don't do what I usually do and swallow a mouth full.
Hope this helps and here is a very simplistic wiring diagram.
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