[Mk2] [Turbo] Fuel Light not working

[gnzyza]

Almost got caught out. The car low fuel light is not working, fuel gauge works fine.

Is there a fuse to check or is this a caused by a sticky float or something?

[Slarty]

Afraid not

It's a resistor of sorts, attached to the fuel level float (it all comes out in one piece if my memory serves me correctly).

There's not much you can do apart from replace the entire assembly with a known working one.

[david123]

I know the bulb can be replaced, perhaps worth checking

[Willenium]

Sorry to drag this up after so long. Wasn't sure if it was worth starting a new thread for it though so here we are.

As a complete opposite, does anyone know about the fuel light staying on? Was driving back from London last night and the fuel light came on. I could see there was fuel and the needle was gradually moving as you would usually expect so I know there is fuel but the light was fully on for the rest if the journey. Is it known for the thermistor to fail like this? I have another sender I can try if it comes to it.

[Peter Gidden]

Sorry to drag this up after so long. Wasn't sure if it was worth starting a new thread for it though so here we are.

As a complete opposite, does anyone know about the fuel light staying on? Was driving back from London last night and the fuel light came on. I could see there was fuel and the needle was gradually moving as you would usually expect so I know there is fuel but the light was fully on for the rest if the journey. Is it known for the thermistor to fail like this? I have another sender I can try if it comes to it.

Most likely bad low fuel sensor in tank.

[Willenium]

Most likely bad low fuel sensor in tank.

Ok I'll try putting another sender unit in. Thanks Pete

[acf8181]

Kinda on topic so will post here....my fuel guage only goes up to 3/4 full when i fil it till the pump clicks....is there any way of adjusting the accuracy?

I know i must have plenty in when i get to mega low on the guage (as i only get about 30 litres of fuel in when pump clicks), but aren't brave enough to keep driving! lol

[Pauln]

The fuel level sender is a simple arm and float, as the fuel level drops the arm moves a wiper arm across a wire wound resistor and the gauge interprets the change in resistance. Over time the electrical contact between the wiper arm and the wire wound coil deteriorates giving a false resistance. This is likely to be the issue, but if it is it's easy to fix just remove the sender assembly, and carefully clean up the wire wound resistor with a piece of fine grit wet and dry. Just don't get to enthusiastic.

If you have a multimeter aim for readings of something like 3 ohms with the arm raised(full tank) increasing to around 110 Ohms arm fully lowered.

You'll need to gently bend back the tabs on the folded metal cover over the wire wound resistor to gain access once you've removed the sender from the car. It's all pretty straightforward.

Paul

[acf8181]

The fuel level sender is a simple arm and float, as the fuel level drops the arm moves a wiper arm across a wire wound resistor and the gauge interprets the change in resistance. Over time the electrical contact between the wiper arm and the wire wound coil deteriorates giving a false resistance. This is likely to be the issue, but if it is it's easy to fix just remove the sender assembly, and carefully clean up the wire wound resistor with a piece of fine grit wet and dry. Just don't get to enthusiastic.

If you have a multimeter aim for readings of something like 3 ohms with the arm raised(full tank) increasing to around 110 Ohms arm fully lowered.

You'll need to gently bend back the tabs on the folded metal cover over the wire wound resistor to gain access once you've removed the sender from the car. It's all pretty straightforward.

Paul

Cheers for the info, popped the sender out (and saw plenty of fuel left despite needle showing empty!), and got my multimeter on it......readings both lowered and raised were spot on....so guessing my guage has is wrong.

Is possible when a mph guage was stuck over the kmh speedo they disturbed the needle to the fuel guage as well and put it in wrong place (they seem to have done this with the speedo too as its about 10mph out!)

[Draven]

Sorry to drag this up after so long. Wasn't sure if it was worth starting a new thread for it though so here we are.

As a complete opposite, does anyone know about the fuel light staying on? Was driving back from London last night and the fuel light came on. I could see there was fuel and the needle was gradually moving as you would usually expect so I know there is fuel but the light was fully on for the rest if the journey. Is it known for the thermistor to fail like this? I have another sender I can try if it comes to it.

I had a similar issue just before I was about to fill up the fuel light came on which was expected. Topped the car up to full then drove home but the light was stiff on and remained on for about a week till it eventually went out.. And now appears to be working fine.

I think it is the low fuel level sensor in the tank that has pretty much had it.

[Pauln]

Cheers for the info, popped the sender out (and saw plenty of fuel left despite needle showing empty!), and got my multimeter on it......readings both lowered and raised were spot on....so guessing my guage has is wrong.

Is possible when a mph guage was stuck over the kmh speedo they disturbed the needle to the fuel guage as well and put it in wrong place (they seem to have done this with the speedo too as its about 10mph out!)

If as you say the readings are spot on, and even though you know there's still plenty of fuel in the tank the gauge shows it's empty, it does sound as though that might be the problem, especially if you're not seeing the low fuel light come on at all.

Did you get them to change all the gauge faces, or just the speedo?

Paul

[acf8181]

Cheers for the info, popped the sender out (and saw plenty of fuel left despite needle showing empty!), and got my multimeter on it......readings both lowered and raised were spot on....so guessing my guage has is wrong.

Is possible when a mph guage was stuck over the kmh speedo they disturbed the needle to the fuel guage as well and put it in wrong place (they seem to have done this with the speedo too as its about 10mph out!)

If as you say the readings are spot on, and even though you know there's still plenty of fuel in the tank the gauge shows it's empty, it does sound as though that might be the problem, especially if you're not seeing the low fuel light come on at all.

Did you get them to change all the gauge faces, or just the speedo?

Paul

Bought car with it already done, so no idea! Wanna change to rev5 clocks at some point so hopefully that will sort it all out, until then i'll just how to work out how to tell how much fuel is left!

[gerbil1028]

Is it a tank out job to remove sensor ?

[Pauln]

If you're talking about the fuel level sender, you can remove this from inside the car.

There's a circular access plate more or less under the ash tray, with the cable going through it. Remove that and you'll see the top plate of the sender screwed to the fuel tank.

So its just a case up un-clipping the "radio trim" and removing the ash tray and it's holder. I can't remember if I took the air con controls out to make a bit more room, or not now. Just keep the car well ventilated while you're working.

Paul

[acf8181]

Yep, very simple as Pauln says....no need to remove blower controls

[Pauln]

They say a pictures worth a thousand words:



Taken from LHD fuel pump swap article at www.mrtwo.net

Paul

[simpson_eh]

can you swap a pump like that or is the hole not big enough to take it out

[Pauln]

Pump access is in a different location, further towards the rear of the fuel tank, so I think you'd have to drop the tank out to do any work on that.