Hj75 troopy twin tanks

Submitted: Friday, Mar 11, 2016 at 13:06
ThreadID: 131803 Views:3973 Replies:2 FollowUps:3
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I just bought a troopy has twin tanks
Under the front seat is a button and two dials
What's the way to swap tanks across ?
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Reply By: Bob Y. - Qld - Friday, Mar 11, 2016 at 13:59

Friday, Mar 11, 2016 at 13:59
Depends whether the aux tank is genuine or aftermarket? Genuine tanks are pressed steel, mounted behind rear axle, between the chassis rails. Early aftermarket tanks were often hang in front of rear axle, sitting close to the tail shaft, while later ones sit behind the axle.

If genuine, there should be an additional pod on top of the dash, with rear tank gauge and a on/off button. When you press the button, a green LED comes on and you are then using the rear tank.

If aftermarket, the switch could be "anywhere", but most likely on the dash. Not sure what the button and 2 dials are? What is on the dials? Almost sounds like an airbag set-up?

Just a word of warning, the 75's, with dual tanks, only had the fuel bypass returning to the front tank, unlike the later models which have 2 solenoids, and the return fuel goes to the tank that is being used. It was best to use at least part of the front tank, before switching to the rear tank.


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AnswerID: 597245

Follow Up By: mike39 - Saturday, Mar 12, 2016 at 16:16

Saturday, Mar 12, 2016 at 16:16
Even with the later models, when switched to the rear tank a bit of crud stuck under a solenoid valve can cause fuel to be taken from both tanks together.
Which one is returning, goodness only knows.
When it happens on mine (both tanks showing fuel usage) I press the button a dozen or more times which lets the crud go to one of the fuel filters and the system settles down again.
Hate to think what goes on with the new v8 diesel with only one filter?
FollowupID: 866320

Follow Up By: pop2jocem - Saturday, Mar 12, 2016 at 17:28

Saturday, Mar 12, 2016 at 17:28
With reference to what Bob has posted, I guess it depends on what year Troopy we are talking about.

My 1991 HZJ75 (ute but same fuel system) has the 1HZ diesel. I am pretty sure the first year Toyota went to that engine as a replacement for the 2H in the 70 series. It has the standard factory long range tank with 4 total solinoids. 2 inlet and 2 return. Also the extra gauge and push button selector switch in a binacle (pod) in the center top of the dash. I have owned a couple of earlier 70 series diesels but none had the extra tank so no switches or solinoids.
I guess if the earlier models only had 1 solinoid the return fuel volume wasn't enough to make much difference. The 2H engines had an in line fuel pump and from memory the only fuel returning from the engine was from the injector bypass lines. Maybe some from the fuel pump but I can't remember.A very small quantity unless one or more injectors were absolutely stuffed. Once again from memory, the fuel from the bypass line was actually fed back into the inlet side of the standard fuel filter so no return to tank required even if the standard Toyota long range tank was fitted.
With the rotary (VE) style fuel pump which had just 1 high pressure plunger element and an integral transfer pump as used on the later 1HZ and the turbo engines they probably needed to circulate a much higher volume of fuel for lubricating and cooling. Hence the necessity to return fuel to the same tank as is being drawn from.

A far as the extra switch and gauges mounted under the seat????? No idea, but maybe as Bob suggested more to do with adjusting air pressures for some after market suspension?????

FollowupID: 866322

Follow Up By: 9900Eagle - Sunday, Mar 13, 2016 at 20:08

Sunday, Mar 13, 2016 at 20:08
Pop, from memory you haven't got alzheimers, you are spot on. The 85 to 99 75 series had the return to the filter with no solenoid and the first 99 1 Hz's had the pod on the dash with the changeover pushbutton and a 4 way solenoid. I can't remember when they went to the second gauge in the the dash display.

One thing is the op's vehicle isn't a Tojo setup and a way of getting over the use of solenoids to feed the return fuel to both tanks, is just put a line between the breathers. If you use the rear tank first it will overfill the front tank and then flow through the joined breather pipes. I definitely know that works.
Now back to my alzheimers, as I discover new things every day.
FollowupID: 866363

Reply By: Shaker - Sunday, Mar 13, 2016 at 08:32

Sunday, Mar 13, 2016 at 08:32
Can you ask the previous owner?
AnswerID: 597297

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