Adjustable Fuel Gauge??

[j7l2]

Due to many members admitting that their fuel gauges read inaccurately, is there an electrical device that could be installed in the wire that feeds the gauge, so that you could calibrate the fuel gauge reading by varying or adjusting the signal(?) that is going to the gauge? I am not good with electrical issues, so this may not be possible. Any of our members with knowledge in this area, care to comment?
Thank you,
JimO

[TurboDiverArt]

I must be one of the lucky ones. Although my gauge fills to past full, I just filled up this morning with 23.5 gallons of fuel and my gauge read just slightly lower than 1/2. It would probably be a little off once I get to 1/4 tank but it being winter I only draw down to 1/2 tank and fill up weekly.

Addressing the issue, it seems plausible. I believe the gauge is a resistance device to determine fuel level. With that said I'd think that adding a resistor to the signal wire would change the resistance at the gauge. The problem is that I don't know if adding resistance would make the problem better or worse. I'd assume the resistance that would need to be added would be small.

I'm sure someone smarter than me and with the proper manuals will know more if it would work or not and what resistance to start with. GMCTD, where are you? ;)

Art.

[gmctd]

Well, since you rattled my chain..... ;)

The GM fuel sender is approximately 100 ohms. Empty is zero ohms, Full is 90 ohms.

The several areas of fault are -

The gage - the magnetic shaft binds, causing non-linear movement. Some free up over time, some do not.

Connectors - outside the truck, can oxidize and become resistive to open circuit, and can be cleaned.

The sending unit - a rheostat, is resistive wire wound, grounded at the bottom end.
The grounded slider wipes up the resistor toward the gage connection, reducing the effective resistance as the tank empties.

Mechanical relationships of float arm to slider, slider to rheostat, rheostat to case\holder can cause non-linearity.

One tank on my truck appears normal, the other registers Full until 5 miles past the last fuel stop (closing as we passed it), then plummets to Empty.

Equally as pesky is the one that drops quickly, then hangs on 1/4 tank forever.

Could not determine the problem with that one, either.

Some GM manuals state - apply 90 ohms to gage, should read between 1/4 and 1/2 tank.
Good accuracy!

Other GM manuals state - apply zero ohms, gage should read Empty, 90 ohms gage should read Full.
(Now that's more like it - musta hired some new engineers!)

Look for short if gage always reads Empty, open if gage reads over Full.

Some folks have reported replacing sender fixed problem, other folks reported replacing sender did not fix problem.

In short, and to wit - I got nothing. ;)

[whatnot]

Originally posted by j7l2:
Due to many members admitting that their fuel gauges read inaccurately, is there an electrical device that could be installed in the wire that feeds the gauge, so that you could calibrate the fuel gauge reading by varying or adjusting the signal(?) that is going to the gauge? I am not good with electrical issues, so this may not be possible. Any of our members with knowledge in this area, care to comment?
Thank you,
JimO You could open your dash and write 1/4 over the top of 1/2. Would be all fixed.

[panchosteam]

Hi guys,something i've done: (it's a lot of work but here it goes)i took the diesel tank down when it was like half way empty or full either way, took the sender out and messured it with a digital meter, that is how you can tell if the sender is good, or is the gauge bad, i've noticed that if the sender is bad the resistance opens or it changes funny, i even open the little housing where the arm and the sender wire reunite and seen that the wire or conductor from point to point is broken.

1984 GMC SIERRA CLASSIC 3/4 TON PICK UP WITH HEATH'S TURBO MASTER AND STILL NO AIR FILTER,ONLY A CLOTH OVER THE TURBO