Dual Tanks - How Do They Work?

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Are you sure its all working properly. I was just reading your very first post and you say you flicked the rocker switch over, green light come on BUT you said the main guage was still dropping down ?? are you sure that when you change over even though the green light is on sounds like to me that its not coming from the reserve but still from the main ?? There is no way the reserve sends any fuel to the main except under pressure when the fuel is hot from a hot day and it pressurises but this would only happen if the reserve is chockers and then it would be minimal. Sounds to me you have an issue with possibly the change over solenoid's even though your mechanic has pulled them apart might still be an issue or this crap your talking about it getting into them and blocking them up and not changing over properly. Would be an interesting trial but maybe wait untill your main tank is nearly empty (sucking air virtually) reserve 1/4 + then flick over to reserve and keep driving and see wether it stops dead due to running out of fuel or not, if it does then some things not changing over under neath, But I would advise to have a 20L Jerry in the back ready to put back in the main tank lol there bloody heavy to push. I would also be having a couple of fuel filters ready to go as this crap that is in the tank is going some where and hopefully the filters doing its job and not going to injectors (doubt it would know by now I reckon) even if there elcheapo filters at least untill all the crap has been removed. Possibly find yourself a second hand reserve tank from a rite off or some thing and whack in. Shame its not the main tank as there are heaps of them around from people going LPG .... Maybe who ever had it before just never ever used the reserve tank who knows. Cheers Steve

[Esses Junior Member Find all posts View Profile Close Esses]

Yeah, it's a weird one. I'm pretty confident that the solenoid/feed-line side of things is working correctly. Even the first time I got underneath with Wifey flicking the switch, the solenoid was clunking quite obviously. I've known this Mechanic for nearly 30 years & he's probably the only Mech. I actually trust at his word. He had it all out, cleaned, checked, re-assembled & "working correctly".
The main tank has been working perfectly, but petrol would only draw from the sub twice now. Once after my Mech. cleared the "gloop" from the junction & again now after I've over-dosed the sub on injector-cleaner. To me that says something nasty in the bottom of the sub being sucked or pushed up the lines & sticking in the junction.
I didn't bother with inj.-cleaner up until now because the engine's actually been going so well & getting better with daily use. It ALMOST feels like it's got new or reconditioned injectors in it. Food for thought?
I'm going to run it on the sub now until Friday & see how it goes. Then fill it up again & see what happens. Fun times.
Take your point on the "experiment". I'll probably try that at some point. I know both gauges work as the main was on empty & the sub on 1/4 when I 1st filled it. Both acting normally since then. See how I go.

[Esses Junior Member Find all posts View Profile Close Esses]

Ok, tanks seem to be working as intended now. Sub is down between 1/2 & 3/4 & main is still hovering around 1/2. It's now covered some 650km since the last fill. When I dumped the Inj. Cleaner in the sub the main-tank gauge was JUST above 1/2. It's now JUST below 1/2 (after approx 180km) which leads me to believe that the pump in the main might be "idling" or still working (& effectively transferring a little fuel to the sub) until the fuel-level drops to a certain point. Knowing Toyota I wouldn't put it past them to wire it that way with an automatic cut-off. At least it's now drawing from the sub.
Petrol jumped to $1-51 today (from $1-35!) so LPG is looking more likely. See how we go.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Petrol jumped to $1-51 today (from $1-35!) so LPG is looking more likely. See how we go.

Depends on where you go, some places (major brand fuel companies) are up to 151.9 and others are still at 131.9, and they say there is no profitteering.......
As a side note steer clear from the 7/11 fuel, I noticed from the last 2 fills that you get no where near as good a fuel consumption as you do with the others, i thought it was because of city driving on the first fill, but the second fill was highway driving, and I worked out the consumption rate to be just over 18ltrs/100, normaly i'm in the 12 to 13 range.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Funny Crooza, as I virtually use 7/11 all the time (round the corner from my house 2k away) and had both tanks full before last trip and returned on the same fuel (didnt need to refuel) and got 11.8 and the trip before same thing 11.6 so Im not complaining at the moment with their fuel lol.......Cheers Steve

[Esses Junior Member Find all posts View Profile Close Esses]

Usually only use Shell or Caltex. The only servo I go near that was cheapish is a Caltex @ $1-35.9 less an 8c voucher. With the price jump I'm going to take advantage of the Prado's long range & damn-well wait till the price comes down again, hopefully.:roll:

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Funny Crooza, as I virtually use 7/11 all the time (round the corner from my house 2k away) and had both tanks full before last trip and returned on the same fuel (didnt need to refuel) and got 11.8 and the trip before same thing 11.6 so Im not complaining at the moment with their fuel lol.......Cheers Steve

Dont forget we are talking different motors here, what I found was in two different states, the first fill was in Sydnet, and the second fill in Brisbane. Using another brand of fuel from United, the consumption went back to normal.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

Sorry Croozza, totally forgot about the motor difference, my old 95 V6 was about 17.2L per 100 round town and 12.2L per 100 on a trip if that gives you any indication, that was with steel ARB winch bar, bigger profile A/T's over factory, cargo barrier, fridge and usual crap.............Cheers Steve

[Esses Junior Member Find all posts View Profile Close Esses]

Ok, this has me beat. This thing's got a mind of it's own. Even though it's been constantly switched to Sub & has drawn 1/3 of a tank from there, now the Main is nearly down to 1/4. How the hell the petrol is getting from the Main to the engine is beyond me unless Toyota has the pump going all the time.
When I bought the Inj. Cleaner there was a choice of petrol or diesel cleaner. I got petrol of course but now I'm wondering if maybe I should "nuke" it with the diesel variety:evil:.
Oh well, at least it runs, I s'pose.

[croozza Avid PP Poster! Find all posts View Profile Close croozza]

Do not put the diesel cleaner in it....
Get the relays and sub tank switch checked out by an auto sparky, you could have a sticky relay, so it is not switching off when on main or sub, so you get both tanks running at the same time.

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

As in previous post, yep thats what I reckon, some thing going on with the solenoids under neath even though the mechanic has had them apart some thing is not operating properly under there and/or also check the switch thats its operating properly also. Cheers Steve

[Esses Junior Member Find all posts View Profile Close Esses]

Yeah, I think you're both right, there's an electrical gremlin in there somewhere. The switch is working, definite clunks from the solenoid in time with the switch & after all, all the switch does is change the solenoid from one position to the other. As a point of interest, mine only has one solenoid underneath - on one of the 3-way junctions - the one controlling the fuel-flow I think. The other junction has 2 1-way valves in it, according to my mechanic. I think that there must be an electrical gremlin with the pumps too as obviously the main is constantly running. As I said, at least the car runs! And runs well.
I think my next step is to drain the sub & see if there's anything nasty in the bottom of the tank. Keep on trying, keep on trying..........................