Fuel Gauge Issue: Tried two senders. Thoughts?

[lomotpk]

Howdy fellow 911-istas.

Fuel gauge used to work, now it's stuck.

Fuel sender unit #1 would show a reading of 1/2 at all times

Bought a used unit from a Pelican, this unit (#2) shows a constant reading of 3/4 full.

Thoughts, tests, experiences appreciated.

Cheers,

Lomotpk
"No heat, but still driving everyday...with the windows and sunroof open no less!"

[Zeke]

You should be able to slide the float up and down before installing in the tank and get the corresponding reading on your guage. If not, obviously it's in your wiring or guage itself.

[lomotpk]

Doh!

Thank you.

[RoninLB]

Originally posted by lomotpk
Bought a used unit from a Pelican, this unit (#2) shows a constant reading of 3/4 full.

there should be a lock pin for shipping

[Wayne 962]

Both are good answers here. Also might be the gauge itself being sticky...

-Wayne

[lomotpk]

I've banged on it like Emilia Earhart over Fiji to no avail.

[vash]

yes, you need to get another one. when you flip it over, you should feel the float slide down fairly easily. i read a PP tech article where some guy took his apart and fixed it. go to the pelican home page and scroll down to 911 tech articles, if interested. personally i would just get another one. you are using a new gasket right?

cliff

[car911]

This may be a sympton of another problem. I went through two sensors before realizing that my gas tank had collapsed a fraction of an inch from the bottom. Just prior I replaced the gas cap which sealed the tank better but resulted in a partial vacuum in the tank as it emptied. The sensor was therefore jamming a bit against the bottom of the tank, resulting in a stuck setting - exactly as you describe, stuck at 1/2 or 3/4! (These sensors are very delicate - very thin aluminum bodies and distort very easily).

[vash]

where are you located?

[Early_S_Man]

The sender is rather simple to disassemble ... use Scotchbrite to polish the nichrome wires ... and be sure the float slides up and down freely full range.

You can test the gauge by substituting a 500 Ohm potentiometer for the sender. Sweep the potentometer full range and the gauge should track without sticking.

[Zendalar]

Is there something u don't know Warren ?

phh..500 ohm potentiometers and such What about the other gauges/sensors ?

You should write small technical article for testing those.

How to measure if the gauges work, how to measure the sensors (ohms in certain temperature and such)

[lomotpk]

Unfixed,

If you are referring to me, I'm in Quincy, Mass a suburb just south of Boston.

[lomotpk]

Early S Man, Thanks for the gauge test. I'll give it a try when the snow stops.

[vash]

let me get this straight, your fuel tank is distorted enough so that your sending unit doesnt fit easily into the tank? i mean the unit is too long, it hits the bottom? if so, that mean you use the five bolts on top to cinch it down, therefore buckling the canister? i cant imagine that. if the sensor fits easy, and the float slides up and down when you flip if over repeatedly, like a party toy. it should work. unless you have another problem with wires and/or guage, and that is where warren steps in.

potentiometer!!! warren, does a standard multimeter have that function?
crap, that was an embarrassing question. couldnt you take a sending unit and plug it in and flip it over to see if the guage moves? opps, nevermind, to many unknowns. guage bad, or unit bad.....who knows.

[fintstone]

unfixed..no a potentiometer is a variable resistor. It usually has a screw or knob to turn to adjust (electronics store or radio shack.. source). You would connect it to your meter's leads with the meter set to the ohms function. In this case, you would want to buy one with a range of 1-500 ohm to emulate the resistance range of the sender. It is a better test than the traditional wiring/gauge test of..ground the sensor wire (0 ohms) for bottom of scale reading or 0, or remove the wire (open)..for full (max)needle deflection as it tests the full meter range.

[vash]

gotcha. thanks i am ohm's law retarded.