Fuel Gauge Help

STW
Posts: 4
Joined: Sat Sep 18, 2021 1:27 pm

Fuel Gauge Help

Postby STW » Fri Oct 08, 2021 8:15 am

Hi. I'm currently setting my fuel level sensor, but I'm having difficulty getting the dash to display the level.

I'm not able to drain and refill the tank so I have a spare fuel level sensor connected to adjust and take readings from. I have the sensor connected to the dash 5v output with a 1k resistor. There are 12 small lines on the level sender which I took readings from. Once I upload the figures to the dash it will read the high and low but nowhere in-between. I've tried changing the max rate of change from 1-10 and the filtering time from between 1,3,5 & 10 seconds but I'm not having much joy. Is there something obvious I'm missing?
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peterguk
Posts: 77
Joined: Mon Oct 27, 2014 10:19 pm

Re: Fuel Gauge Help

Postby peterguk » Fri Oct 08, 2021 7:15 pm

Those voltage readings are way too low.

What's the resistance of the sender when in the full and empty positions?

STW
Posts: 4
Joined: Sat Sep 18, 2021 1:27 pm

Re: Fuel Gauge Help

Postby STW » Sat Oct 09, 2021 1:35 pm

15ohm full 295ohm empty

peterguk
Posts: 77
Joined: Mon Oct 27, 2014 10:19 pm

Re: Fuel Gauge Help

Postby peterguk » Wed Oct 13, 2021 8:37 pm

15ohm full 295ohm empty
A pull up resistor of 150 ohms will give you a voltage spread from 0.455V to 3.3V. Not a wide spread, but will be sufficient.

Watch you total current draw on the 5V supply. The lower the resistor value, the higher the current flow. Standalone 12V to precision 5V are easily available for a few £s if needed.

STW
Posts: 4
Joined: Sat Sep 18, 2021 1:27 pm

Re: Fuel Gauge Help

Postby STW » Fri Oct 15, 2021 7:31 am

Thank you for the help. The only other sensors connected to the 5v are 2 temp and 1 pressure sensors and wires as supplied by RT.


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