Fuel Gauge Light

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JoeDiese
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Mon May 14, 2012 10:29 pm

Driving along today and the low fuel light came on. The actual gauge itself was still showing plenty of fuel remaining, approximately an eighth of a tank, above the red. About where it ought to be with the amount of petrol I put in last and the amount of miles covered.

I haven't done enough miles for all the fuel to have gone again.
Yet the light is on.

Is it possible the float in the sender is partially sodden with fuel and sitting lower in the sender intank, enough to set the light on whilst still reading a measurable amount on the gauge?

Any ideas?

This is my first e30 with the 63litre tank, so I'm not too hot on the symptoms of a dodgy sender on the two sender tanks...
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rich318i
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Mon May 14, 2012 10:38 pm

trust the light not the gauge
Grrrmachine
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Tue May 15, 2012 5:46 am

rich318i wrote:trust the light not the gauge
Very much this. Gauges aren't exactly accurate technology, but the light is accurate enough to serve as a warning.

If you want to, you can test the senders as outlined here:

http://www.e30zone.net/e30zonewiki/inde ... el_Senders

but you'll probably find them in order; you just need to brim the tank and drive it till the light comes on again, so that you know what sort of range you can get from 55litres (63l - 8l reserve).
JoeDiese
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Tue May 15, 2012 8:52 pm

Considering that until now the light and the gauge have been in sync, in that the gauge will be on empty for a while and then finally the light comes on; yet this last time the light came on whilst the gauge reads far from empty this leads my to think one of the sender units is reading wrong. As there are two senders in series in the tank, I am thinking that one float has absorbed some fuel, making it less buoyant. Surely this would allow the light to come on early, as with the other sender still reading low resistance, and averaging that with the high resistance from the other sender.

Is this scenario plausible or can the floats not absorb fuel? I've never opened a sender up to know whether the float is of foam composition, or a plastic capsule that could rupture or what?
JoeDiese
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Wed May 16, 2012 6:32 pm

No one got any insight here??



Well hopefully I'll find a second right-hand side fuel level sender in a scrappy this weekend, fit it and see if that fixes the issue.

...and I'll post whether or not it was the fix for anyone searching this in future.
Grrrmachine
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Wed May 16, 2012 6:35 pm

The Wiki outlines how to test the senders. Without doing that, you're just throwing parts at the problem in the blind hope it'll fix it, when there's the chance of introducing a new problem.
Captain_Birdseye
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Fri May 18, 2012 9:01 am

where is the low fuel light?
macas
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Fri May 18, 2012 9:06 am

Captain_Birdseye wrote:where is the low fuel light?
Your joking,right? :D
Captain_Birdseye
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Fri May 18, 2012 9:13 am

no
Grrrmachine
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Fri May 18, 2012 9:22 am

It's part of the fuel gauge, next to the red area signifying Low Fuel.
Captain_Birdseye
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Fri May 18, 2012 9:30 am

yep, i see it now.
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Rich320I
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Fri May 18, 2012 11:26 am

Captain_Birdseye wrote:where is the low fuel light?
i get a tan from mine its on so much :D
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