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Fuel gauge

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Boggie
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Joined: Wed Jan 31, 2018 3:57 pm
Location: Buckinghamshire UK

Fuel gauge

Post by Boggie » Thu Feb 01, 2018 5:51 pm

Hi all,

When empty my fuel gauge reads 1/3. I have removed the sender and tested resistance. 3.2 ohm on full and 73 ohm on empty. I can hear the float inside slide up and down anb in both cases it appears to hit the end stop. If I short the wires the gauge reads full, if I disconnect it reads empty so not sticking.

Any ideas please?
1985 M635CSI
Classic Car Collector & Restorer.

baders
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Joined: Sun Nov 23, 2014 7:38 am
Location: Perth Australia

Re: Fuel gauge

Post by baders » Fri Feb 02, 2018 1:06 am

The values you tested appear OK for the sender unit. I made up a tester using a 100 ohm variable resistor to test back the other way to the cluster and gauge. See my post in the LOCUTUS build thread.
1986 635csi LOCUTUS
Arktis Blau Metallic / Pearl Beige
S38B36/Close ratio dogleg 5sp
Perth Australia.

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Soperman
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Location: London, UK

Re: Fuel gauge

Post by Soperman » Fri Feb 02, 2018 8:48 am

A finger of suspicion is pointing towards the circuitry behind the instrument cluster here, a common ailment on these cars.

Other symptoms often include erratic temperature gauges and haphazard service indicator lighting etc so if you have any other gauge or instrument issues directly behind the steering wheel you might want to investigate further; and you dig deep enough into this forum you will find a tonne of information on resolving such problems.

Good luck.
E24 M635CSi

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Boggie
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Joined: Wed Jan 31, 2018 3:57 pm
Location: Buckinghamshire UK

Re: Fuel gauge

Post by Boggie » Fri Feb 02, 2018 12:34 pm

Thanks chaps!

I will add it to my list. I will have a dig aroung tge forum when I get a moment. Are the issues easy to see/resolve and could the rechargeable battery in the dash be affecting this?
1985 M635CSI
Classic Car Collector & Restorer.

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