Low fuel light

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EFH
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Low fuel light

Post by EFH »

Morning all,

I have a question, my Patrol (2000 4,2d) has only the main tank - as far as I know 95l. I drove it till the needle was at the bottom of the red line of the fuel gauge ( as far as i dared - not wanting to push... ). I did notice, thanks to some handy late afternoon sun, something that looks like a little light next to the gauge.

1. Is it the low fuel light?
2. When does it switch on?
3. If its dead, where do I start looking for the problem?

I did fill up and only got 82.7l in.
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2000 Nissan Patrol 4.2 Turbo Diesel GL
Burnco Replacement Bumper, Suspension Lift, Terrain Taimer 'erd
Turbo Conversion by Sojo Automotive - Michael Steyn
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ricster
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Re: Low fuel light

Post by ricster »

I have the same Patrol...also no subtank fitted unfortunately. That little circle you see there is the orange light that should come on when the fuel is low. Mine comes on more or less on the line or a fraction below. I've only seen it light up a few times as bleeding diesel from the tank to the pump is not a fun thing to do if you do run out of diesel.

If you don't have a drawer system in the back, maybe you could lift the carpet and open the little hatch to get access to the tank sender unit. ( I assume this will work, never tried it myself ) Remove the plug, undo the bolts holding it in place, connect the plug again and with the ignition on, slowly lift the unit out and watch the fuel gauge when it is completely out if the light doesn't glow, then there is a different problem, but electrickery is not my strong point.
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Cedric
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EFH
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Re: Low fuel light

Post by EFH »

ricster wrote: 13 Jun 2019 08:18 I have the same Patrol...also no subtank fitted unfortunately. That little circle you see there is the orange light that should come on when the fuel is low. Mine comes on more or less on the line or a fraction below. I've only seen it light up a few times as bleeding diesel from the tank to the pump is not a fun thing to do if you do run out of diesel.

If you don't have a drawer system in the back, maybe you could lift the carpet and open the little hatch to get access to the tank sender unit. ( I assume this will work, never tried it myself ) Remove the plug, undo the bolts holding it in place, connect the plug again and with the ignition on, slowly lift the unit out and watch the fuel gauge when it is completely out if the light doesn't glow, then there is a different problem, but electrickery is not my strong point.
Thanks, I'll have a look this school holiday, Ill see if there are any obvious issues wiring wise. I do I.T. not wiring.
2000 Nissan Patrol 4.2 Turbo Diesel GL
Burnco Replacement Bumper, Suspension Lift, Terrain Taimer 'erd
Turbo Conversion by Sojo Automotive - Michael Steyn
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Re: Low fuel light

Post by iandvl »

Disclaimer: I do not know diesels.

TB45 and TB48 you need to relieve the pressure of the injection before opening anything. Literally, start the car, pull the fuse for the petrol pump and wait for the truck to die (which is not long, considering the rate at which us petrol folk burn fuel... :rolling: )

The empty indicator sender is at the bottom of the fuel level sender/pump armature. It looks like a little cylinder, with an electric wire coming out of it. Highlight below.
20190613_161833.jpg
20190613_161833.jpg (43.24 KiB) Viewed 5231 times
There is a process for testing this, but I am not near the manual at the moment. Will post the process for this as soon as I can. Basically, remove the fuel sender / pump armature and to test for continuity with a multimeter with the empty sensor in a jug of water and out.

My gut feeling is that the wire for the empty sensor has come loose. But I cannot remember if empty is normally open (ie: no continuity) or normally close (continuity). Will check the manual when I am in front of my computer.
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ricster
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Re: Low fuel light

Post by ricster »

On a diesel, unless there is a boost/lift pump fitted as aftermarket, there will be very little pressure in the fuel pipe, unlike the petrol motor
Regards
Cedric
Nissan Patrol GL 4.2 Diesel Turbo (Iron Maiden)
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EFH
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Re: Low fuel light

Post by EFH »

Thanks for that, gives me a place to start looking!
2000 Nissan Patrol 4.2 Turbo Diesel GL
Burnco Replacement Bumper, Suspension Lift, Terrain Taimer 'erd
Turbo Conversion by Sojo Automotive - Michael Steyn
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iandvl
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Joined: 12 Jan 2015 13:26
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Re: Low fuel light

Post by iandvl »

Sorry - I've not had a chance to post this yet.

Extract from the manual below detailing how to test the full / empty sender with a multimeter.
empty-sender.png
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Ian de Villiers

Patrol 4.5 GRX
Jurgens XT65 2x0 with Super Select Zero
ORRA: H80
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