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Fuel Gauge Help

Posted: Fri Oct 08, 2021 8:15 am
by STW
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?

Re: Fuel Gauge Help

Posted: Fri Oct 08, 2021 7:15 pm
by peterguk
Those voltage readings are way too low.

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

Re: Fuel Gauge Help

Posted: Sat Oct 09, 2021 1:35 pm
by STW
15ohm full 295ohm empty

Re: Fuel Gauge Help

Posted: Wed Oct 13, 2021 8:37 pm
by peterguk
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.

Re: Fuel Gauge Help

Posted: Fri Oct 15, 2021 7:31 am
by STW
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.