a long one but hear me out:

[acl]

Still screwing with the fuel gauge on the 68. Have read many post and diagrams and still troubled. I have continuity from wire at sending unit to tan wire at dash plug, no prob. Have power to the pink power feed at the dash plug no prob. Have purchased new gauge ( 3rd one to try) and no reading or needle movement 1st question The new gauge has a white piece on back from the two terminals but nothing else. Should there be a "resister" or something else other than just the plastic piece? if yes should it not have come with anew gauge or is that a item itself? 2nd question looking at the the post on troubleshooting the fuel gauge it states that with the gauge removed to ground the caseing, ground the ground tab and add 12 volts to the hot side. it states the gauge should read empty and then removing the ground from the sender post it should jump to full. ALL 3 of the gauges I have when hooked up this way goes to approx 4 or 5 o'clock position and will not move back at all, they just stay there. What am I missing?? Bad gauges ,? When rempoving the sender wire nothing happens with the gauge at all so I not sure my gauge or sender is working. Both new but that does not always mean anything. I am perplexed. Am i testing the gauge correctly? I am following the famous trobleshooting guide but maybe misinturputing it. Help please This is getting old and i am sure some are tired oh hearing me moan about it SORRY. Thanks to those who read and respond. Gary

[Dynomutt]

The answer to this could be just as long or longer than the question (I know because I started typing it all and abandoned that in a hurry).

I think I would start by testing the sending unit. Measure ohm's between the sending unit chasis and the terminal. Ohm's should gradually change as you move the float from "empty" to "full". If that works the the sending unit should be ok. Also make sure the sending unit and gauge have good grounds. The guages vary quite a bit so a pic might help. Is it a stock gauge? Does it have two or three terminals on it? They basically work by putting 12vdc on one post, one post will be a chasis ground (or they will use the housing for this in a two post) and one post for the sending unit wire. With power on, as the ground signal changes on the ground pin, the gauge raises or lowers.

This is just how I understand them to work. Someone else may have a better/more understandable answer.
Still a long winded answer.

[Sammy]

If you pull your float out of the tank measure ohms on it while working the float up n down all the way up should be 90 ohms. Ensure you have a good grd on the tank. Then check the wiring from tank to the fuse box. Not grded out under the sill plate? Insure ur plugged in on the fuel gage fuse box? After checking good ground for the dash, only thing left is resistor on back of the gage as is the usual suspect.

[acl]

I do have a stock gauge, 3 terminals on back, have tried to rest as you mentioned, but did not use sending wire, will try. also as I stated in the novel above, the new gauge has a white piece between the two terminals but nothing else, I have seen some with a small wire on top of the white piece as well as orange piece of "tape" on top of the wire. thanks for the help. Gary

[70c10]

Contact board member "byrd". He will have the answer since he has rebuilt thousands of these