fuel guage problem

[rustyescott]

ok folks here is what i've got 1987 c10 swb single fuel tank. fuel guage does not read right , runs out of fuel at half a tank .did this with old sending unit still does this with a new sending unit. guage oms out correct. does this with every fuel guage i use. what do i check now.

[Liberty]

Probably the sending unit is getting stuck.

[rustyescott]

new sending unit

[midnight rambler]

Hows the ground look

[tucsonjwt]

Have you tried a brand new gauge or a used one? I don't know of anything involved except sending unit, ground, gauge and the wiring in between (unless dual tanks.) My gauge read the same way and a new gauge fixed the problem. If you used an aftermarket sending unit I would suspect that also.

[rustyescott]

i've got 10 plus fuel guages , does this with every one of them . did this with old fuel sender , still does this wite new fule sender . spectra brand sender.

[enaberif]

You need to be checking your grounds.

[hatzie]

The gauge has a ceramic calibration resistor on the back of the gauge coil cannister. If it's cracked or not making good contact it'll cause the gauge to malfunction the way you describe.
If the gauge itself has stared to fail that'll cause this too.

The other thing that'll do this is increased resistance in the sender circuit... but that'll cause the needle to read super high, past the Full line on the face, when you fill it.