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Discussion Starter · #1 ·
So, my reserve light doesn't come on.
My authorised dealer tried replacing the complete fuel gauge unit, but none of the two spare units (used) he had on stock had a working Reserve sensor.
Hmmm...
Then I had a looksee for relevant info on here. It appears the reserve sensor was discontinued by Honda sometime early 2000s.
Hmmm...

We're talking about the reserve sensor. Not the fuel gauge.
The reserve sensor is a small cylindrical thing, sat on a metal rod a fixed distance from bottom of petrol tank. Wire going in (or out...) and holes on both ends, allowing petrol to enter the can and air to escape.
But how does it work? What's inside?
And why does it cease to function?

Thoughts:
Some sort of small ball moving inside, getting stuck.
Electrode inside, getting oxidised?

Ways to fix the sensor? Ultrasound treatment to dislodge crud and oxidation? Chemicals?

Do you know?
 

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Also, there are generic units available such as .... this also has a good write-up on how they work

 

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Discussion Starter · #4 ·
Also, there are generic units available such as .... this also has a good write-up on how they work
Bang on! Exactly the info I was looking for. Thanks a bundle.

This kind of device is known as an NTC resistor; Negative Temperature Coeficient - the hotter the less resistance. As opposed to PTCs who work the other way around. Eg PT100 sensors, who measure 100 ohms at 0 deg C and increase by 0.385ish ohms per degree as temperature rises. You find those in things like meat tempsensors for kitchen use.

Now that I know what to look for, diagnosing and replacing the sender unit becomes a lot easier.

Topic closed.
 
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