duel tank change-over switch

Larry,

Diesel or petrol? I can't comment on diesel, but my petrol experience may be helpful. Others more familiar with your vehicle may be much more help.

My '87 FJ75 petrol machine, much older than yours , uses 2 changeover valves under the floor below the driver. One of these selects which tank to draw from, the other which tank to return excess fuel to. You can get serous problems if either valve isn't working properly, as fuel will be drawn from one tank but excess returned to the other. One tank can become seriously overfilled and fuel will be forced out through the filler or through a couple of paths to the carburetter. I've had this happen to me and with huge pressure behind it, after I'd stopped for the day, fuel was forced into the carby, liquid ran down into one cylinder, hydraulic lock, $$$$ for an engine rebuild.

This may be completely irrelevent to your situation, but suggest find the changeover valve/s and if you have two such valves, be concerned. If you do have to replace them, suggest using a single 6 port valve rather than a pair of 3 port ones. With a common actuator there should be less risk of them not being synchronised.

If you do have two seperate valves, suggest temporarily swap over the two inlet lines on the feed valve (so you're drawing from the "other" tank) and also the two output lines on the return valve. If the fault remains, but moves to the other tank, you've found your problem. It is one or other of the valves.

In the meantime, suggest not filling the tanks all the way. Leave room for your unintended fuel transfer. Could save you a heap of $$$$$$.

HTH

John

Larry. My cruiser was a bit younger than yours but I thought they had solenoids on the duel fuel lines. The switch closed one solenoid and opened the other. I had to replace one of mine and aftermarket it still was around the 100$ mark. Others with better cruiser knowledge should know.

I got away from the problem of wiring up a duel tank. I use the main all the time, so I have gauge and Return line. I just have an electric pump to transfer fuel from the axillary tank to the main tank. Cheers Tony

Larry.
Assuming it is diesel.
I had an'85 hj75, now a hzj75 and this identical problem has occurred on both.
The fix is easy, but a bit bldy. messy.
You will find the 2 solenoid valves bracketed to the chassis rail under the driver door.
Pull the hoses off (move spring clip first) and have a plug handy to stop the fuel loss, it come out fairly fast as the pipes are below tank level.
I found that a .303 shell makes an excellent plug!
Then remove the valves and disconnect the terminal plugs.
Now the fix.
Get a couple of short lengths of auto wire and crimp a female connector to one end and an alligator to the other. You can now connect to 12v. and activate the solenoid, immerse in some diesel and slosh around. You will see debris come out which was holding the valve seat open. You can also blow through it to make sure it is free.
Just blowing, flushing without opening the solenoid will not clear it.
We often get fuel from drums when working in the bush, I suspect this is where it comes from.
Actually mine is now doing it again, time for another diesel soaking!
Good luck, but that will fix it, and no replacement parts needed.
furph

Hi, Thanks for the info guys,btw its a diesel. Sounds messy, might wait till I'm really really bored.ha ha

Cheers,
Larry