Sub Tank Issue (1 Viewer)

[ather90]

Hey everyone, recently acquired a 97 LC, the PO said the sub tank works, i read up on how to fill it up ( open the fuel lid, pull the knob up and fill), but whenever i tell the guy to fill it up, he says its already full and wont fill. the gauge next to the alt meter says empty (could be the fuse?, if so where would i find it?) but when i press the Sub T button, the small green light lights up for 2 seconds and then nothing happens..

any help please? i live in the middle east and use this car for cross border travelling

 

[FnLexus]

Ive found when filling the subtank, the nozzle cannot be shoved in all the way and you cant go full bore with the trigger.

 

[alia176]

Hey everyone, recently acquired a 97 LC, the PO said the sub tank works, i read up on how to fill it up ( open the fuel lid, pull the knob up and fill), but whenever i tell the guy to fill it up, he says its already full and wont fill. the gauge next to the alt meter says empty (could be the fuse?, if so where would i find it?) but when i press the Sub T button, the small green light lights up for 2 seconds and then nothing happens..

any help please? i live in the middle east and use this car for cross border travelling

Do you have the oem or Long Ranger subtank? I have the oem 16g subtank and fill it like the main tank, no fussing. When the tank is full, the gas station nozzle stops automatically.

 

[ather90]

Do you have the oem or Long Ranger subtank? I have the oem 16g subtank and fill it like the main tank, no fussing. When the tank is full, the gas station nozzle stops automatically.

thats the thing, if its full already why wont the button work? the light shows up for like 2 seconds and then nothing happens, also the sub tank fuel gauge is below the E line, i'm really confused

 

[paj4x4]

The sub tank will only transfer fuel to the main tank if the main can accommodate the fuel from the sub tank. For example if your main tank is at half level of more the sub tank will not transfer fuel to the main one. HTH

 

[ather90]

The sub tank will only transfer fuel to the main tank if the main can accommodate the fuel from the sub tank. For example if your main tank is at half level of more the sub tank will not transfer fuel to the main one. HTH

My main tank was almost empty, according to the guy at the station, the subtank is full, but still it wont work, is there a fuse somewhere to check? because the subtank gauge needle stays below the E mark

 

[alia176]

thats the thing, if its full already why wont the button work? the light shows up for like 2 seconds and then nothing happens, also the sub tank fuel gauge is below the E line, i'm really confused

Show me a picture of your transfer button pls.

 

[ather90]

Here are the pics of the gauge, button and the tank

Sub Tank Button:


The Tank knob


The Gauge:

 

[alia176]

Ok, thanks for the pics. I wonder if the PO installed this system completely OEM style if he used the ECU made by George on this board. Since you're in the middle east, you may have an OEM transfer system.

I'm not sure how the OEM subtank system works but I have the ECU made by George. If the sub tank is indeed empty, and I push the Sub T button, it'll only stay on for 2 seconds or less. This is because the Ecu thinks that the sub tank is empty and the transfer pump is NOT suppose to run dry and ruin itself.

So, what you need to investigate is whether or not the sub tank is indeed empty.

First and foremost, remove the plastic cover located in the driver side rear wheel well by removing three 10mm screws. You'll see the hoses that go from the filler neck to the two fuel tanks. Take a look at the filler hose that goes to the subtank to see if its kinked in any way. If it's kinked, then there is your problem.

If the hose isn't kinked then you need to find out if there is fuel inside the sub tank. You can try to siphon the petrol out of the subtank into couple of 5 gallon container to see how much petrol is in there. If only three gallons or so comes out, then your subtank is in fact empty.

If more than five gallons come out, then the subtank is NOT empty but your fuel level sending unit thinks that it is empty. At which point, further electrical troubleshooting of the sending unit is in order.

I hope all this made sense to you!

 

[ather90]

Ok, thanks for the pics. I wonder if the PO installed this system completely OEM style if he used the ECU made by George on this board.

I'm not sure how the OEM subtank system works but I have the ECU made by George. If the sub tank is indeed empty, and you push the Sub T button, it'll only stay on for 2 seconds or less. This is because the Ecu thinks that the sub tank is empty and the transfer pump is NOT suppose to run dry and ruin itself.

So, what you need to investigate is whether or not the sub tank is indeed empty. You can try to siphon the gas out of the subtank into couple of 5 gallon container to see how much gas is in there. If only three gallons or so comes out, then your subtank is in fact empty.

If more than five gallons come out, then the subtank is NOT empty but your fuel level sending unit things that it is empty. At which point, further electrical troubleshooting of the sending unit is in order.

I hope all this made sense to you!

thanks for the reply, how would i empty out the subtank?

 

[alia176]

You can empty the subtank two ways:
- remove the large drain plug at the bottom and drain the tank into a large container.
- siphon the petrol out by sticking a long hose down the filler neck.

I'd check the hose to see if it's kinked.

 

[george_tlc]

More likely than not it is an OEM setup straight from the factory.

If the tank is indeed not empty, then given the gauge reads empty and the fuel transfer ends immediately, it's quite possible that the sender assy in the tank is faulty (maybe the float is no longer 'floating'). With the OEM subtank models there is an inspection panel in the rear floor (just like for the main tank) where you can pull the sender out to inspect it. Pull the carpet/vinyl mat in the rear up and see if an inspection plate is there (over the subtank area). That will give you easy access to the sender assy without having to drop the subtank.

cheers,
george.

 

[richmondbob]

I have the OEM subtank installed by the PO and I've followed his instructions for filling up both tanks since owning the LC.

1. Pump the gas yourself. Sub-tanks are not the norm so it's not surprising you've had trouble when letting gas station clerks fill up your LC.
2. Main tank fill: Make sure the tank knob is pushed in all the way, stick the pump nozzle in and fill the main tank first until it's full.
3. Sub-tank fill: Pull the pump nozzle out, pull the tank knob out and then put the pump nozzle back in to fill the sub-tank.
4. Finish up: Once the sub-tank is full, remove and hang up the pump nozzle, push the tank knob back in, close the gas flap and you're done.

Now because I'm not the greatest mechanic on the forum and you wrote that it was the gas station clerk who said your sub-tank was empty, I'd recommend the following to find out if there's a problem with your sub-tank:

1. Run your main tank down to Empty.
2. Go to fill-up but you're only going to fill up the sub-tank (pull tank knob out and fill) and attempt to pump 20-gallons in. If you've got an OEM sub-tank this would fill-up the sub-tank forcing the remainder into your empty main tank.
3. Jump back into your LC, start it up and check your main tank's gas gauge. IF your main tank needle has moved up, then 'yes', it looks like the gas station clerk was correct that your sub-tank was full and indicates a looks like you have a problem with the sub-tank system. However, if your main tank has only gone up a little, then 'no', your sub-tank was actually empty in which case you can fill-up both tanks and get on with some LC-related fun.

Pardon the instructions - I'm not trying to be an ass, just really thorough in my response .

 

[Hsn]

Hey everyone, recently acquired a 97 LC, the PO said the sub tank works, i read up on how to fill it up ( open the fuel lid, pull the knob up and fill), but whenever i tell the guy to fill it up, he says its already full and wont fill. the gauge next to the alt meter says empty (could be the fuse?, if so where would i find it?) but when i press the Sub T button, the small green light lights up for 2 seconds and then nothing happens..

any help please? i live in the middle east and use this car for cross border travelling

Did you ever solve this midstory. I have the same issue, even though i replaced the float valve, sub tank button works fine, green light kicks in. i can hear that the valve between my tank has opened. So my next trouble shooting step is to fill up the sub tank to see if the gauge reads anything. even though I have tested that step before and have 50 sar worth of gas in it.

 

[ezhilan]

Hey everyone, recently acquired a 97 LC, the PO said the sub tank works, i read up on how to fill it up ( open the fuel lid, pull the knob up and fill), but whenever i tell the guy to fill it up, he says its already full and wont fill. the gauge next to the alt meter says empty (could be the fuse?, if so where would i find it?) but when i press the Sub T button, the small green light lights up for 2 seconds and then nothing happens..

any help please? i live in the middle east and use this car for cross border travelling

I seem t have the same issue could anyone help me as the subtask meter doesn't seems to read when the fuel is filled

 

[logicbyondreaso]

It very well could be a bad connection to ground for the level sensor.
Is your subtank oem or was it added to a US 80?

 

[ezhilan]

It very well could be a bad connection to ground for the level sensor.
Is your subtank oem or was it added to a US 80?

it is gem subtank and a gcc spec