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mishu

How To Read Fuel Sensor Signal?

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mishu

Hello,

 

can anyone tell me how to read the fuel sensor?

I'm working on a project to replace the original instrument panel in a 1.1 205 with a LCD, controlled by a microcontroller.

I'm at school right now, and don't have access to the car (to read the wires from the sensor with a multimeter). I have the instrument panel with me, but I don't know what to apply to the fuel gauge inputs.

The back of the fuel gauge on the 1.1 has 3 inputs. From the wiring guide on the main site, and from other earlier testing I had done, I was able to work out what they are:

fuel.png

Can anyone please confirm if these notations are correct, and what signal I have to connect to the 'Signal' input?

Does the fuel gauge work like an ohm-meter, measuring electrical resistance in the sensor? Or does it read an electrical signal, like a voltmeter?

I really need to confirm this so I can proceed :)

Thanks!

 

mishu

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Richie-Van-GTi

the sender is a kind of potentiometer where tyhe float arm rubs against the contact strip to give varying resistance :)

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mishu

So I'd need to use an ohmmeter to measure electrical resistance between the signal input and ground?

 

mishu

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Super Josh

Well, you could either measure the resistance with an Ohmeter or, better still, you could apply a voltage across it, say a regulated 5V (if you use the battery voltage this is not stable enough and your readings will vary depending upon whether the engine is running etc.). Then just measure the variable voltage coming back on the signal line :)

If you use a Microcontroller with an inbuilt Analogue to Digital converter, then the only external circuitry you will need is the regulated 5V.

 

 

 

Josh

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mishu

Yes, I am planning to use a microcontroller with an integrated ADC.

 

Where should I apply the 5V? I don't know where the fuel sensor inputs are located, I assume that's what I should connect the board to? I was hoping to solve this from the instrument panel loom alone...

 

Also, isn't there a fire hazard associated with applying a voltage to the inside of a gas tank?

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