Setting up duel tanks - best way to set up???

[brad 93hilux]

Hey i have a toyota hilux with a prado 80L tank under the rear of the tray, and since the coil conversion i removed the factory tank and have left it out..

Now i'm going to put a 2nd tank in under the body near where the factory tank used to be but was wonedring whats the best way to set this up?

I did a search and found a few guys saying to have it set up to syphon from one tank to the other, but was wondering what other guys have done and what works better...

Also how you wired in the two seperate fuel gauges?

Cheers Brad

[V8Patrol]

I had little faith and sucess with the syphon setup.....

punctured tank meant loss of both tanks contents


I then made them seperate identies with a switch controling the pumps so I could choose between the tanks, thus making my weight distribution a "choosable option"

On the last setup I did for a mate I left the stock system as is.... and the reserve tank is hard wired to the low fuel light.....
Low fuel light on - pump automaticaly switches on and pumps into std tank till low fuel light goes off.
OK .... he's an idiot and has run the tank dry a few times .... diesel engines dont like that !!!.....
The reserve tank has a buzzer fitted and activates only when the reserve tanks low fuel warning light is set to come on. He hasnt run the system dry as yet but hates the buzzer


Advantages to this system:
1/ idiot proof
2/ several warnings of low fuel not just one warning
3/ no confusing switches that can accidently be bumped on/off
4/ buzzer is well hidden so he cant disconect it = goes to a servo
5/ second fuel guage only needs an occasional glance after warning light appears.

[Chucky]

My 80 had the setup where it sucked and returned to the same tank. So you could completely empty one tank then change over to the other.
My 60 sucked from one tank and returned to the other. Which is alright while the second tank is full as it just overflows into the suck tank, but when it get abit lower you need to use the transfer pump to pump it over.

Out of the two I much prefer the 80's system of two seperate tanks, Also if you hole one of the tanks you can still switch tanks and get home.
As for the fuel guage, I'd use a relay system, so the one (Factory?) guage shows how much fuel you have left in the tank you are sucking from.

[brad 93hilux]

yeh i'd much perfer to have two seperate tanks as i like the idea of being able to switch (isolate one tank) if you have any problems...

Also i was thinking of measureing the size of the space i have under the truck and going to the wreckrs and having a look at all different cars/ 4bys and see what is the best size i can get...

But if i use a relay like you have used and the tanks are from two different manufactures, whats the chances of it working? ie electrically are they all the same, or best to stay with toyota...etc

Cheers
Brad

[oldmate]

look at the setup on a 80 series diesel. that is what you want. The 80 series petrol pumped from the sub to the main tank because it is fuel injected. This way means you only need one fuel pump - in the main tank.

you should be able to get the fuel switches of an 80 and wire it up pretty easily.

You'll find wiring is identical on almost all cars. There's not much in it anyway. A fuel level which can wire up to any aftermarket guage, and a low fuel level light which you don't really need anyway. A good aftermarket guage would incorporate that anyway.

[big lux]

On our work utes we run a little elec lift pump from the secondry tank to the main on a swith on the dash. Good side is you watch the gauges cause is in your head. down side is if you do run the main out without pumping the second into it yur stuk on the side of the road for 10mins while u pump into the main.

[chimpboy]

On our work utes we run a little elec lift pump from the secondry tank to the main on a swith on the dash. Good side is you watch the gauges cause is in your head. down side is if you do run the main out without pumping the second into it yur stuk on the side of the road for 10mins while u pump into the main.

Hook the pump to the "low fuel lamp" circuit on the main tank, problem solved.

[brad 93hilux]

The only prob with that is i dont have a low fuel light, hilux never had one and the prado tank did not either...

But i will look into getting the switchs off a 80.

I did however remove the efi fuel pump out of the prado tank and have it sitting at home in the shed (did not need it on the hilux diesel) so possibly use that too.. But a bit weary of using it, running it and getting air in the system...

[chimpboy]

It's up to you how you do it but personally I would prefer to keep it simple, and just have the second tank set up to fill the main tank when necessary. I can see why it could be good to have two independent tanks with their own fuel pumps etc but it is not keep-it-simple-stupid kind of stuff.

To be honest in some ways the best system is a big fat hose from the bottom of the higher tank down to the filler of the lower tank (plus a little breather back up again I guess), basically acting just like one big tank, no extra pump just gravity.

Are you sure the prado tank hasn't got a low fuel sensor though? That seems unusual, how many wires go into it?

edit: i'd also rather have two gauges than one gauge that switches between tanks, it's not much good if you switch over to tank B only to discover that it's even emptier than tank A!

[brad 93hilux]

yeh not 100% sure but the prado tank only had 1 extra wire then the hilux tank, and that was connected to the fuel pump..

So if it is there, i'm not sure how to wire it up

Cheers