Low fuel light? do i or not

[Flashover428]

Hi to all, just scored myself a 2002 4.2ltr turbo diesel limited plus ute which i luv already so thought this would be a good site to join. One question if someone can help please is has my patrol got a low fuel light? It has twin tanks but not sure about low fuel light and also if it dose, dose it work off either tank? Hope someone can help. Regards Paul

[macca86]

just so you know the fuel is only taken from the main tank. If you push the sub tank button it tops up the main tank never goes from sub to motor like a toyota one does.
A little red lights comes on when fuel is low. well maybe more orange than red.

[gbab01]

One other quirk with the sub tank that got me for a while is it that at a certain point it starts sending a small amount of fuel to the main each time you start up. I think this is designed to not allow the fuel in the sub to go stale. It gives the impression you are using the fuel (which you are but from the main - not the sub). Mines a 2.8 but I am sure it is the same for all.

[nissannewby]

I must have a problem with mine cos i can see where the light is in the dash but have tested its operation lol (stuck on side of road) It is pretty much where the fuel gauges are and as stated a orange/red colour.

[Flashover428]

Thanks for the responces, good to know there is one, and yes I seem to notice the sub tank slowley creeping down even with fuel in the main so now I know why. dose make it a little had to get an accurate fuel consumption though. Thanks, Paul

[the evil twin]

Thanks for the responces, good to know there is one, and yes I seem to notice the sub tank slowley creeping down even with fuel in the main so now I know why. dose make it a little had to get an accurate fuel consumption though. Thanks, Paul

Do your fuel readings with either the sub empty or fill them both after an economy check. I always fill both tanks at the Servo anyway.

If your the curious type (and I am assuming the Utes are the same as the Wagons except in sub tank capacity), take the main tank filler cap off and about 2 inches down you will see a small pipe outlet on the side of the filler neck.
That is the pipe from the sub tank transfer pump. If you turn the ignition to "On" you will get fuel coming out for 15 seconds or so while the system does a self test if the main is not full.
All Nissan do is literally pump fuel from teh sub tank into the filler neck of the main.

[macca86]

to do your fuel consumption it is no harder. Fill up both tanks drive till light comes on fill up then do the math with km driven vs amount of fuel added. I get about 13 L/ 100 km city driving and all highway driving about 10.5 L/ 100 km

[Fity]

Sorry to hijack the thread, but would my 2000 zd30 have a low fuel light? I am right on empty for the first time with an almost full sub and there is no light. Only a sub light comes on when the ignition is turned on. What does it look like?

[macca86]

the fuel light wouldn't come on I'd think as you have an almost full sub tank. mine is a little round light just near the E symbol you can see it if you look closely with out it being on

[Fity]

Thanks Macca. I will transfer the sub and see if it comes on when the main gets low again.

Where is the needle when it comes on? Before empty, on empty or after empty? How much fuel is left when it comes on?

[Fity]

The light just came on, orange circle to the left of the E. I turned the sub on and it went out after 10 seconds. Any one know how much fuel is left when it turns on?

[teno45]

I tested mine last week, calculated to have less than 10 liters of diesel left in the main with full sub when the fuel light came on.

Any idea how much fuel is transferred on start? When I filled up last week there was a two liter discrepancy between Bowser and scan gauge. I put it down to a different Bowser. I usually fill up from the same Bowser each time. But I also didn't drain the sub this time.

[Fity]

Yeah I was thinking that the sub would transfer more over the course of using a full main tank. My Sub was still reading over the full mark when the light came on.

I think the sub pump runs for about 15 seconds when you start up and it took my sub about 8 mins to transfer half (about 15l). My rough calculations is around 1/2l. So 10 starts = 5l. But I don't think the automatic transfer occurs till the main is down a bit.

Does the sub pump have a filter? I thinking that it should and would need replacing.

[the evil twin]

How much is left for low warning?... varies from truck to truck depending on dings in the tank bottom and position of the thermistor in the tank etc. Seems to be about 10% remaining roughly.

Sub pump filter?... don't think so. If there is it isn't one designed to be "serviced".

Sub pump rate?... I'm sure I saw it quoted as 1.2 to 1.5 LPM somewhere and certainly seems what most people experience so Fity's numbers look normal.

[Fity]

Also looking at the flow rate in the main tank filler neck seems to confirm the same rate.

[macca86]

Thanks Macca. I will transfer the sub and see if it comes on when the main gets low again.

Where is the needle when it comes on? Before empty, on empty or after empty? How much fuel is left when it comes on?

Pretty much covers the E symbol. I've pushed 50 km with the light on and then was 117 L to fill up wouldn't do that again