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Connecting to Miata Fuel Sensor
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Post Connecting to Miata Fuel Sensor 
Hi, so AnalogX reads as as 0-5V signal, I am not a radioshack, build a component type guy.. I like to buy things Smile

Anyone know of something I can put inline to map Miata Fuel tank Level back ?

Here's the Miata Fuel Sensor specs and research from a few forums..

Gauge 110 ohm adjustable fuel converter

Looks like 12V
Gauge is 110-0 ohm fuel sender (Mazda Miata)

Engine Running vs. Not can change Ohm's (there's a calibration), you can check on your voltmeter.

Full: 3 ohms
3/4: 15.8 ohms
1/2: 32.5 ohms
1/4: 64.2 ohms
E: 110 ohms

notes:
i believe the fuel sender is a variable resistor, so the signal to the gauge in the cluster is a resistance value, something in the neighborhood of 0 to 90 or 100 ohms. I think there is a tap out on the back of the cluster where you can read the voltage from the gauge, but if you remove the cluster you wont have it.

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The original cluster has a pull-up resistor, which translates the fuel gauge reading into a voltage divider network.

https://learn.sparkfun.com/tutorials/voltage-dividers

You can enable the built-in 2.2K pullup resistor for shiftX2 by bridging the solder pad, or you can add a pull-up resistor externally. The 2.2K resistor is mostly designed to work with high resistance temperature sensors - the more common application. So, an external 220 ohm pullup resistor might work better for you.

There's also a handy voltage divider calculator here that will show you the output voltage based on the varying resistances:
http://www.ohmslawcalculator.com/voltage-divider-calculator

Hope this helps Smile


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