fuel sender voltage

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Willem
Posts: 25
Joined: Wed Jun 30, 2021 11:32 am

fuel sender voltage

Post by Willem » Thu Jan 27, 2022 5:59 pm

Good afternoon all,

The fuel gauge on the tourer is not working, a little while ago it started working after driving for several miles but it has now given up completely, the oil sender has also stopped working. I have 7.6V at the fuel sender, is this correct or should it be 12V, on the fuel gauge the double wire at the back reads 12V but the single wire reads 7.6V. The fuel sender unit does have a Ohm variation from 31.2 (empty) to 87.2 full and varies nicely trough out the swing of the float. Am I looking at a problem in the fuel gauge?

Regards, Willem
Rover 12 Tourer, 1936
Range rover L322, 2009

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luli
Posts: 569
Joined: Sat Jun 04, 2011 6:49 am
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Re: fuel sender voltage

Post by luli » Fri Jan 28, 2022 11:42 am

I hope the following may help
PetrolOilmeter.jpg
PetrolOilmeter.jpg (29.93 KiB) Viewed 740 times
Rover 10 1946 RHD
Rover 10 1947 LHD
Rover 12 1947 tourer LHD
http://lulisml.wordpress.com/

Willem
Posts: 25
Joined: Wed Jun 30, 2021 11:32 am

Re: fuel sender voltage

Post by Willem » Fri Jan 28, 2022 9:20 pm

Thank you for the schematic, I am a bit mystified why there is only 7.6V on the single terminal, (this is the one that connects to the fuel sender), I guess that is why there is no reading on the fuel gauge, too low a voltage. There is a series of pages from a chap in the USA who completely dismantles a fuel gauge (found in a previous post on the site here), something I don't feel terribly confident about, the miniscule size of the wires and my ham fistedness is not the best combination.
I think I'll see if there isn't a more qualified person about for this job in my vicinity.
Will
Rover 12 Tourer, 1936
Range rover L322, 2009

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luli
Posts: 569
Joined: Sat Jun 04, 2011 6:49 am
Contact:

Re: fuel sender voltage

Post by luli » Sun Jan 30, 2022 2:17 pm

Solving the circuit indicates that the sender resistance is now ~300 ohms. Probably corrosion, bad contact, etc. Also the gauge itselff is mechanically stuck. Try to hit it several time (gently...) and better oil it with clock's oil.
Rover 10 1946 RHD
Rover 10 1947 LHD
Rover 12 1947 tourer LHD
http://lulisml.wordpress.com/

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