REFLECTOR: Re: Reflector Digest, Vol 9, Issue 68-Fuel Feed-blinking low fuel warning

[Bob Kuc]

The ones that I have found in mostly the asian models look like a tip of a bullet with holes in the top and bottom to allow for gas to penetrate it.  Inside this unit is some type of resistor that has a very high resistance when fuel is touching it and very low when dry.  Another feature that I have found with this that if one was located at the bottom of the sump, and water is present, the resistance changes enough to allow for an LED to light dimly.  

I have gone to those "pull em yards" and dropped many tanks to get these little buggers for testing.  As long as you put 5 volts through there nothing happens,  I did put 12 through there and it got cherry red in that little canister.  Kind of spooked me from using these in the fuel tank.  I do have an optical sensor for my sumps.  If you want to replace the float, you might want to think about replacing it with the fuel level senders that the factory uses.  Hook it to a gauge and you will see exactly how much you have in there .

Bob
> 
> Yes. Nearly every car with a low-fuel warning has one. Most I believe, 
> are photoelectric sensors. I know a guy who has one in his fuel line 
> that lights when his tank runs dry.