Fuel Gage Woes

[Bill Pritchard]

I have searched here and on the Chevelle website, and looked at a number of youtube videos on the subject......and I'm still unclear on the problem I have.

The problem: all of a sudden, the gas gauge on my 69 Chevelle (which had been working only half-assed accurately) went to WAY past full and stayed there. Did some tests based on reading past threads and looking at youtube videos, and best guess was that the sending unit went bad. So, I dropped the gas tank and pulled the sending unit out. Using an ohm meter on the sending unit, I find that at the low point of the float (i.e., empty tank) it reads 10 -15 ohms. Moving the float to the high point (full tank), it reads 120 - 125 ohms. When I take the sending unit and hook it up in the trunk of the car with the tan wire (from the gauge) connected to the sending unit and the ground wire from the sending unit to a good ground in the trunk, moving the float on the sending unit through its full range of motion (with the ignition switch on) has no effect on the pointer on the gauge....it stays WAY past full. When I completely disconnect the sending unit, and just ground the tan wire from the gauge, with the ignition on, the gauge moves perfectly to the 'E' mark. Unground the gauge with the ignition on and it returns to WAY past full.

Any ideas?