OEM Subtank Retrofit/Install Project With Pics (3 Viewers)

[snailman]

Well I managed to get the short harness by a miracle as they seem harder to come by even here in Australia! So everything installed and working properly! The only gremlin I have is the sub tank gauge not working.
Can someone point me in the right direction of where I can check. I'm guessing at the gauge itself I should be able to check resistance from a wire to earth to see if the system is working and the issue is the gauge otherwise at the rear of the vehicle the 6 pin short harness that goes to the fuel sender check between a pin and earth to see the sender is moving.
Does anyone know what kind of reading the sub tank sender should read? Eg. 0-90ohms etc.
Thanks!

 

[alia176]

Well I managed to get the short harness by a miracle as they seem harder to come by even here in Australia! So everything installed and working properly! The only gremlin I have is the sub tank gauge not working.
Can someone point me in the right direction of where I can check. I'm guessing at the gauge itself I should be able to check resistance from a wire to earth to see if the system is working and the issue is the gauge otherwise at the rear of the vehicle the 6 pin short harness that goes to the fuel sender check between a pin and earth to see the sender is moving.
Does anyone know what kind of reading the sub tank sender should read? Eg. 0-90ohms etc.
Thanks!

If i'm not mistaken, your sub tank and main tank sending units have the same resistance (while empty, while full), which I can't recall the number at the moment. Someone correct me if I'm mistaken!

 

[TomH]

If i'm not mistaken, your sub tank and main tank sending units have the same resistance (while empty, while full), which I can't recall the number at the moment. Someone correct me if I'm mistaken!

I use the stock gauge for both the main and the sub tank.

@george_tlc has the pinouts for the sub tank sending unit on his site which may be helpful.

Auxiliary tank

www.george4wd.taskled.com

 

[snailman]

So I'm getting approximately 8v at the rear plug going to the sender (sender is unplugged). Sender is measuring about 110ohm at the moment with some fuel in it. That seems I'm the ballpark of where I'd expect it.
I'm guessing this should be 12v and the power eventually comes from the gauge pod? I've got a couple more checks to do as it could be a corroded pin or something.

 

[logicbyondreaso]

So I'm getting approximately 8v at the rear plug going to the sender (sender is unplugged). Sender is measuring about 110ohm at the moment with some fuel in it. That seems I'm the ballpark of where I'd expect it.
I'm guessing this should be 12v and the power eventually comes from the gauge pod? I've got a couple more checks to do as it could be a corroded pin or something.

i would bet it’s a corroded pin. Most likely where you connect to the truck via short harness from subtank.
Do continuity checks from there. I’ve had this happen on 2 trucks I added tanks to.

 

[snailman]

i would bet it’s a corroded pin. Most likely where you connect to the truck via short harness from subtank.
Do continuity checks from there. I’ve had this happen on 2 trucks I added tanks to.

I tested at the 6 pin plug that is part of the body harness to get that readibg that rules out the short harness to the subtank sender. I did have a look underneath the passenger floor but couldn't see any connections there.

 

[snailman]

If someone could confirm what voltage they have going out towards the sub tank sender without the sender plugged in that will help me immensely

 

[cruiserdan]

If i'm not mistaken, your sub tank and main tank sending units have the same resistance (while empty, while full), which I can't recall the number at the moment. Someone correct me if I'm mistaken!

Correct. The sweep is the same.

 

[XennonYazon]

I tried to buy one from cruiserparts, they can not source the part any more.

Any other sources for the fuel transfer pump?

 

[gummycarbs]

Any other sources for the fuel transfer pump?

I know nothing about the factory pump, but if they're NLA then I would look at Facet fuel pumps. They're used in small aircraft and have become somewhat popular in the motorcycle world. Very dependable and quiet, and they have a huge range of pressure and volume choices.

 

[cruiserdan]

I've been using one of these for over 17 years.

 

[XennonYazon]

I know nothing about the factory pump, but if they're NLA then I would look at Facet fuel pumps. They're used in small aircraft and have become somewhat popular in the motorcycle world. Very dependable and quiet, and they have a huge range of pressure and volume choices.

Ok

 

[XennonYazon]

Ok, thanks!!! I will look into those.

 

[XennonYazon]

I've been using one of these for over 17 years.

View attachment 3204995

Thanks, thanks!!!

 

[MoCoNative]

Voltage to the sender is approximately 5v, the voltage is created through the gauge itself. 12v goes to the gauge, then it grounds through the sender as I recall. DO NOT PUT 12v to the sender, as me how I know. All the magic smoke on the resistance wire will be released.

I assume you are trying to hook this up to the OEM overhead console? Is all the wiring in place? Sometimes the gauge can be sticky, stuck dirty. Make sure you have a good ground from the top of the sender access into your loom. The sender grounds through the body, to the sender mount piece.

 

[snailman]

Voltage to the sender is approximately 5v, the voltage is created through the gauge itself. 12v goes to the gauge, then it grounds through the sender as I recall. DO NOT PUT 12v to the sender, as me how I know. All the magic smoke on the resistance wire will be released.

I assume you are trying to hook this up to the OEM overhead console? Is all the wiring in place? Sometimes the gauge can be sticky, stuck dirty. Make sure you have a good ground from the top of the sender access into your loom. The sender grounds through the body, to the sender mount piece.

Hey mate. Thanks for the detailed reply! I ended up changing out the gauge as it appeared to be the only thing that I wasn't sure on and BAM. a working install
Thanks again

 

[Tedward]

I use the stock gauge for both the main and the sub tank.

@george_tlc has the pinouts for the sub tank sending unit on his site which may be helpful.

Auxiliary tank

www.george4wd.taskled.com

so you have a switch that gets a signal from the main or the aux tank?
I would like to do that.

 

[TomH]

so you have a switch that gets a signal from the main or the aux tank?
I would like to do that.

Switch gets it's signal from both the main and the sub and then switches to the gauge.

I copied @cruiserdan

I have gas......but how much?

I completed my subtank installation today by adding a switch to toggle between the main and subtank senders. I made the switch out of a rear heater switch. It was not quite configured as I needed it so....I REWIRED IT...! :D :D

forum.ih8mud.com

And my circuit. The switch as shown in the diagram is a modified rear heater switch.

This is an unmodified rear heater switch so you can see the difference.

 

[logicbyondreaso]

Doing another install of a factory subtank into an LX450 (USA). OEM setup. Planning to make an installation video for the group.
Not pictured: subtank, correct main tank, and overhead console.

 

[Madcrix12]

whats the cost to do one of these from a

Doing another install of a factory subtank into an LX450 (USA). OEM setup. Planning to make an installation video for the group.
Not pictured: subtank, correct main tank, and overhead console.

View attachment 3301277

parts perspective?