Sub Tank General Questions

[rookiepatroller]

Hi fellas,
I recently bought a series 2 GU ST 3.0L. Being a complete newby to the patrols I wanted to know if the sub tank switch was de-energised when the sub tank is empty? I would put some juice in and try it but it's in getting some minor things sorted out and nads etc. I'm thinking that if i can't switch it over there may be something at fault but if its just the ecu not allowing it to switch bcos its empty then I'm all good.

Cheers

[Yendor]

There is a low fuel sensor in the sub tank and a full fuel senor in the main tank.

The transfer pump will not work if the sub tank is empty or the main tank is around/above 3/4 full.

If you push the fuel transfer switch (engine running) with the sub tank empty the light in the switch should come on for a couple of seconds then go out.

[my third 256]

engine doesnt draw from sub tank it only transferes to main tank
With the sub full or with fuel in it and the main low push the switch in and aorange light shows on mine.
Fuel is now transfering but its slow, takes maybe 1/2 to an hour to pump over.
F Y I ...re the sub tank , if you undo both fuel caps you can see the fuel being pumped into the main tank from the sub tank from near the opening .....interesting ...i thought it was pumped straight into the main through the guts ....anyhow this is one way to see if fuel is going in, if you dont have any warning light issues that is ....!!!!!!

[rookiepatroller]

There is a low fuel sensor in the sub tank and a full fuel senor in the main tank.

The transfer pump will not work if the sub tank is empty or the main tank is around/above 3/4 full.

If you push the fuel transfer switch (engine running) with the sub tank empty the light in the switch should come on for a couple of seconds then go out.

Sub switch light doesn't illuminate at all. Thanks mate, looks like I've got more issues to sort out.

[Yendor]

It could be just a blown bulb in the switch. Your not really going to know if there's a problem until you put fuel in the sub tank.

If you think it's been awhile since the sub tank has had fuel in it, it may pay to check the condition inside the sub tank before putting fuel in it.

There's an inspection plate in the floor just behind the drivers seat (above the sub tank) Lift up the carpet, remove the plate, from here you can get access inside the sub tank.

[rookiepatroller]

Champion!! Cheers mate I'll check it out.

[Bulbous]

Sub switch light doesn't illuminate at all. Thanks mate, looks like I've got more issues to sort out.

Well maybe not. When my sub tank is entry the switch is just dead. No lights nothing. When the sub tank is full and the main is down a bit, It transfers in about 10-15 mins. So I know it works.

[sooty_10]

When I run my sub tank and it's getting empty the light switches off. Then when I push it again it will come back on for several second/min and then go out again. It will only do this several times before it will no longer energise at all. So if the fuel level is fully below the empty sensor it will not energise the switch or light at all. I'd be putting $5-10 fuel in the sub first before trying to pull anything apart and see if the switch works then.

[the evil twin]

I've just spent quite a few hours sorting out my Ute sub tank fuel issues and I think Sooty is on the money

If you aren't getting an orange "Sub Tank" warning light on the main instrument cluster then there is a good chance (not 100%) but a good chance everything is OK as the system self tests every start.

As others have said it will not transfer fuel if either of the level switches are 'made'. AFAIK the light in the switch should illuminate for a few seconds if the sub is empty... but... I think it may not illuminate at all if the 'main tank full' switch is made (could be wrong on that tho)

The nominal flow rate of the Patrol sub tank transfer pump is 1.5 litres per minute so if you have a wagon expect it to take 20 minutes give or take to transfer 30 litres. More if you have a ute or a long range sub. My ute has an 80 litre sub and it seems to take forever compared to the Wagon with it's 30.

Wack 5 litres in the sucker, have less than 1/2 a tank of fuel in teh main and see if she works

[rafa]

Well maybe not. When my sub tank is entry the switch is just dead. No lights nothing. When the sub tank is full and the main is down a bit, It transfers in about 10-15 mins. So I know it works.

Interesting that you say it transfers in 10-15 mins, mine would take a couple of hours!