Outer Limits 4x4 Board

Has any one else had their sub tank slowly empty into the main tank without asking it too?

If my sub tank is full I will get several hundred extra k's before the main tank is empty and the sub tank only ready 2/3rds after starting full.

im a little baffled as the sub tank sits lower than the main.

just curious if its happens on all gu's or if there something i need to fix.

IIRC the fuel pump runs from the sub tank each time the engine is started.
Then at some time? supply changes back over to main tank.
Sounds like the sub tank pump is not shutting down???


cheers

yeah mine sorta does that to. fill up sub tank to full, then 2 days later its down on the guage, with out touching the pump out button. thats in an 2000 ute.

sub tank pump runs for a couple of minutes every time you start it ...
its normal.

Yep, it's normal.

As already said, the pump runs for 60seconds every time you start your engine. Apparently it does it to keep the pump lubricated and in working order.

As far as I know it only does it if there is fuel in the sub-tank.
The pump shouldn't come on with an empty sub tank (Pump would seize without the lubrication/cooling of the fuel).

how interesting / annoying. though probably necissary.

just makes it hard to keep a little spare fuel in the sub tank as a safety blanket. seeing as it doesnt seem to have a fuel light and when it says empty it really is

2003 ute

wow, seems strange the utes wouldnt have a fuel light, i know my 2002 ST wagon does,

ozy1 wrote:wow, seems strange the utes wouldnt have a fuel light, i know my 2002 ST wagon does,

can anyone confirm or deny? mine an 03 dx ute.

its caught me a couple of time now. and the last 1/4 goes pretty quickly so easy to get caught on. my plan to just keep the sub tank with some fuel isnt working lol

yeah i'm also pretty sure the utes don't have a fuel light , i had one for 3 years and had it well under the empty mark a few times and no light ever came on .
the draining over is a bit annoying .

mines a 99 and i have run out a few times ... no light.

I know its pov pack and that utes get boned on the upspec front, but... thats a bit poor nissan.

such is life.

My old 2004 ST ute had a fuel light, and so did my 2000 DX.

what if your sub tsnk doesnt have any fuel in it???
does it still pump dry???
i have had the same problem.... thought it was dodgy neighbours syphening out of my sub!!!! i think i might pull the wires off the sub until i need it, or put in a missile switch.

thanks for the info b oys

BushRanger7 wrote:what if your sub tsnk doesnt have any fuel in it???
does it still pump dry???
i have had the same problem.... thought it was dodgy neighbours syphening out of my sub!!!! i think i might pull the wires off the sub until i need it, or put in a missile switch.

thanks for the info b oys

earlier in the thread it was noted that they dont run when dry. its kind of annoying but at the same time id rather not have that pump crap out on me.

Im just going to fill up the main and add 10L to the sub every tank to allow for it and still have the back up.

nayto I think you meant that your main tank has a fuel light not the sub tank.

Mine does all the same things previously said and very normal. NO aux tank fuel light. The thing i find strange is that they dont swap over automatically when the main is out. Doesnt matter just strange.

2005 ST ute

[gubeaut] wrote:nayto I think you meant that your main tank has a fuel light not the sub tank.

Mine does all the same things previously said and very normal. NO aux tank fuel light. The thing i find strange is that they dont swap over automatically when the main is out. Doesnt matter just strange.

2005 ST ute

I actually meant fuel light on main tank not sub tank. I dont have a fuel light on my main tank...

mine either, 99 ute, mite have blown. i hope

thehanko wrote:

[gubeaut] wrote:nayto I think you meant that your main tank has a fuel light not the sub tank.

Mine does all the same things previously said and very normal. NO aux tank fuel light. The thing i find strange is that they dont swap over automatically when the main is out. Doesnt matter just strange.

2005 ST ute

I actually meant fuel light on main tank not sub tank. I dont have a fuel light on my main tank...

Cool no probs. I know my mates truck has one and its a '00 or '01 but its an ST like mine so dont know if it was an ST thing or not.

Yeah my 2004 DX ute also doesnt have a light, i've run it out a couple of times. And just like previously stated the last 1/4 goes very quick, in like 75kms or something. I've always wondered why my aux tank never fills the main (even though it is slightly smaller then the main) but if it pumps everytime you start then that would explain it

xrmeier wrote:Yeah my 2004 DX ute also doesnt have a light, i've run it out a couple of times. And just like previously stated the last 1/4 goes very quick, in like 75kms or something. I've always wondered why my aux tank never fills the main (even though it is slightly smaller then the main) but if it pumps everytime you start then that would explain it

aux tank is smaller than main as well so it will never quite fill it. plus it takes like 40 min to pump over during which time your using fuel if still driving.

but im totally stoked that mr nissan saved himself a few $ by not putting in a fuel light on the dx. come on its pov pack not 1950's pack.

[gubeaut] wrote:nayto I think you meant that your main tank has a fuel light not the sub tank.

Mine does all the same things previously said and very normal. NO aux tank fuel light. The thing i find strange is that they dont swap over automatically when the main is out. Doesnt matter just strange.

2005 ST ute

to my knowledge their is no lights on the dx models and have never had lights on the sub tank.

as for the no swapping the over even though it is called a sub tank they arnt think more that they are a oversized in car jerry can with a pump attached. the nissans never made them so that would have a change over probably because they were 2 lazy.

as for the issue of fuel goin down nissan put a timer relay into they system so that every time you start your car your sub tank would pump into your main tank so that the car is always garanteed fuel and yes that means that they run dry 2 my knowledge it wont hurt them 2 much over shorts amounts of time but i would probably advise puttin fuel in the sub ever 2 weeks or something just so u dont fuck the pump... as for me i now only fill my sub tank pump half into my main and then over the next week it slowly pumps down and by the time i have to fill up again both are empty at the same time...

cheers
Heath
--Zer0--

Anyone's sub tank pump operate randomly when the vehicle is off? I have been out bush a few times (you can hear it because its so quiet) in my swag tied to the side of my 06 ST ute and hear the pump go on by itself quite regularly...very weird.

Also pretty sure mine has a fuel light for the main tank, but I never run it that low to avoid sucking all the water and crap up out of the bottom of the tank.

chunks wrote:Anyone's sub tank pump operate randomly when the vehicle is off? I have been out bush a few times (you can hear it because its so quiet) in my swag tied to the side of my 06 ST ute and hear the pump go on by itself quite regularly...very weird.

Also pretty sure mine has a fuel light for the main tank, but I never run it that low to avoid sucking all the water and crap up out of the bottom of the tank.

your fuel pick up point doesnt change, so your sucking up the same place wether the tank if full or empty.

wish i had a fuel light. just have to use my brain instead

zer0 wrote:

[gubeaut] wrote:nayto I think you meant that your main tank has a fuel light not the sub tank.

Mine does all the same things previously said and very normal. NO aux tank fuel light. The thing i find strange is that they dont swap over automatically when the main is out. Doesnt matter just strange.

2005 ST ute

to my knowledge their is no lights on the dx models and have never had lights on the sub tank.

as for the no swapping the over even though it is called a sub tank they arnt think more that they are a oversized in car jerry can with a pump attached. the nissans never made them so that would have a change over probably because they were 2 lazy.

as for the issue of fuel goin down nissan put a timer relay into they system so that every time you start your car your sub tank would pump into your main tank so that the car is always garanteed fuel and yes that means that they run dry 2 my knowledge it wont hurt them 2 much over shorts amounts of time but i would probably advise puttin fuel in the sub ever 2 weeks or something just so u dont . the pump... as for me i now only fill my sub tank pump half into my main and then over the next week it slowly pumps down and by the time i have to fill up again both are empty at the same time...

cheers
Heath
--Zer0--

I have a DX .. the main has a fuel light .. the sub is a pump over style arrangement apparently due to the low fuel tank volume ,shape and position ..hence the engine would constantly lose fuel when the car moved forward or back .. the sub fuel pump should run for between 10 and 60 seconds to maintain the pump and fuel lines after starting.. if there is any issues with the pump ie fuse blows .. then a fault light will light on the dash

hey guys I have a 98 Gu wagon which i filled up 2wks ago, from there it has slowly emptied the sub into the main although now the main is still half full and the sub is empty?? does this mean that sub tank relay/ fuse is faulty and it is pumping for longer than 60secs start-up??

Thanks Matt.

I suppose it would depend on how many times you start your engine over the 2 weeks .. and the actual flow of the pump .. from memory the sub is only 28L .. I find it a pain in the arse to be honest as I always try to keep my sub half full

thehanko wrote:

chunks wrote:Anyone's sub tank pump operate randomly when the vehicle is off? I have been out bush a few times (you can hear it because its so quiet) in my swag tied to the side of my 06 ST ute and hear the pump go on by itself quite regularly...very weird.

Also pretty sure mine has a fuel light for the main tank, but I never run it that low to avoid sucking all the water and crap up out of the bottom of the tank.

your fuel pick up point doesnt change, so your sucking up the same place wether the tank if full or empty.

wish i had a fuel light. just have to use my brain instead

Yeh I just think that the more fuel you have in the tank the more it will dilute the other crap in there, whether its true or not who knows.

umm i have a 99 gu wagon 4.2 turbo d and mine will start draining to the main once i hit 1/4 in the main but other than that it dosnt move!

My 05 Ute does it too, got that bad when on trip over the simpson that I stuck a pair of vice grips on the line. That stopped it ! Oh and my sub tank computer is long gone so my is a manual pump switch now..
So they do siphon or push fuel back into the main for some odd reason ..

Seems as though the sub tank on Nissan ute's is a bit of a mystery.... I was out in Kakadu on the weekend exploring and when the main tank was almost on empty I switched the Sub Tank button on. I kept driving down the highway thinking all was good, until I was on a long straight and had done a few k's and the engine lost power and stopped ....? I pulled off the road turned the ignition off then back on and tried to start it again, it didn't start, it had the mad wobbles a Diesel engine has when its out of Fuel ..? I was a little confused at this stage my sub tank was about 3/4 full, sub tank light on and the main tank sitting on empty. Anyway I left the ignition on for a while still had no fuel transfer over. So I did a painstakingly task of taking diesel from the drain hole of the sub tank into a 1L wine bottle from our garbage that we were carrying back and slowly transferred a few Litres into the main tank. I then primed the hand pump in the engine bay and got it running again. So I made a b-line trip to a Cooinda to fuel up the main tank. Once we were back on the road again and I had used a 1/4 from the main tank I turned on the Sub tank again to see if it would work and it did it started filling up my main tank again. So I don't know if the pump is playing up or there is a trick to this. Any ideas on what I may have done wrong or issues people have had before..?

Oh and of all the Nissan Patrols that went past and other people that I was hoping might stop and offer a hand or ask if we were okay, a 80 series Cruiser owner from NSW pulled up to see if we were okay.