fuel gauge wacky on front tank only

[mrfixit]

If that screw has any type of coating at all (such as a self-drilling screw) it may be insulated from the hole.
That would be better if you wire-brushed the flange to clean metal, then used a small bolt, nut, and solderless connector on the wire with a loop or fork end.

 

[Fellro]

I personally stand by the resistor being bad on the sender itself, which requires replacement of the sender. Seen that happen a lot, and a new sender fixes it.

 

[mrfixit]

Definitely a possibility... even likely. Just cancelling out the easy stuff first. especially since grounding it worked originally.

 

[tomtoc]

one last fact/observation before i assume its the resistor on the sender (which i won't fix any time soon).

it only happens when the engine is "under load". the gauge is fine in the driveway. it's fine on flat, level, highway.

it goes screwy when i'm shifting through gears in town, or going up a hill on the highway.

its not necessarily an rpm thing either. on the highway it will be fine at 1800, but if i hit a hill and push the gas harder, it will happen - even if the rpms have dropped to 1500.

does that make any sense or change any answers?

 

[blacksnapon]

one last fact/observation before i assume its the resistor on the sender (which i won't fix any time soon).

it only happens when the engine is "under load". the gauge is fine in the driveway. it's fine on flat, level, highway.

it goes screwy when i'm shifting through gears in town, or going up a hill on the highway.

its not necessarily an rpm thing either. on the highway it will be fine at 1800, but if i hit a hill and push the gas harder, it will happen - even if the rpms have dropped to 1500.

does that make any sense or change any answers?

Yep, still a ground! The engine has to be grounded to the frame, the body, grounded to the frame.

 

[subford]

Yep, still a ground! The engine has to be grounded to the frame, the body, grounded to the frame.

Not true.
The Frame is grounded with the battery ground cable (trucks only, not vans) and with some slip-on ground straps for static from the body to the frame.
The grounding of the frame from the battery ground cable is for the trailer ground through the frame.
The Fuel Gauge is grounded to the body (at the Radiator support drivers side) and not the frame and the body must be grounded for the gauge to work right.

Check the Fuel pump/gauge plug (C440 in diagram) about two feet from the tank.
Either the ground is opening from the gauge sender (C440) or the power to the sender is opening (C440, C205 or selector switch). Could also be the sender but sounds more like wiring. The tank is not grounded with the exception of a poor ground from the sender lock ring.

 

[tomtoc]

old thread, but i finally got a picture of it - thought it was worthy to share

that's all