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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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Brent Picasso
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Post Can't connect to Miata Fuel Level Sender 
Hi there,

We have been trying to make the Miata fuel gauge input work according to the instructions found here on the Forum but didn't succeed. For some reason nothing in the RaceCapture Fuel Level gauge reading changes when we apply different settings in the Analog Sensor config (raw, linear, mapped). No matter what we choose the gauge always reads like 500 gallons. Since the tank is almost full, our voltage reading at the fuel level sender is ~0.5V, so we assume what we really are reading at the gauge are the Millivolts coming from the sender. For some reason it does not get translated according to the mapping defined in the analog sensor setting. Any ideas what might be configured wrong?

We are racing at 24 Hours of LeMons at Thunderhill in California this weekend (car on track already).

Thx much in advance.

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Hi,

We have a specific how-to video on connecting and calibrating a fuel level sender - see https://www.youtube.com/watch?v=Cb3eBNv5yI0&list=PLZdfZf8eVujn2VSIXR5I-PPQSYS25xW5j&index=9

This should help you get started. let us know how it goes!


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Brent Picasso
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