C1 Gas gage reading is inaccurate

[Jim K.]

I have a little problem with my gas gage reading inaccuratly. When the needle is almost on E and I stop to fill it up it only takes about 8 to 10 gals. of gas to fill it (the gas pumps shut off like it's filled). The gas gage reads full. The gas gage also appears to move quicker from full to half then it does from half to empty when I'm driving (I haven't checked it with milage).
I have replace all the wiring in the car and installed a new sending unit, vent hose, a new filler neck hose. I have not restored the gage. I would appreciate any ideas or suggestions. Thank you in advance for any help

[Rob M.]

Re: C1 Gas gage reading is inaccurate

Hi Jim,

Test the circuit first by removing the sending unit from the gas tank. Connect the metal of the sending unit with a crocodile clip and wire to the gas tank to ensure correct grounding. Now move the sending unit lever by hand and read the gauge. If it is ok than it is possibly a wrong ground connection due to dirt.

If it isn't ok, hook the ground wire to a more solid ground spot (e.g. the frame (on a spot without paint) and check again. If it reads fine now the gas tank isn't properly grounded. Correct this problem by adding a wire (out of side) to from the gas tank to a spot on the frame (e.g. using a gas line clip bolt).

If it is still not working as it should check the gauge.

greetings,
Rob.

[Jim T.]

Re: C1 Gas gage reading is inaccurate

Just drive it, from what you mention you are not going to run out of gas if you fill it up when it gets on the empty mark. I have been driving my 68 since about 1975 with the same movement of the guage like yours and have never run out of gas.

[Jimmy Johnson]

Re: C1 Gas gage reading is inaccurate

Jim,

I had a similar problem with my 59. It would read no more than 1/2 tank when it was full and would not return to empty when I turn the switch to off. I had my wires hooked wrong on the ignition switch. There are two red or pink wires that are almost exactly the same color that plugs into the switch. I reversed these two wires and it fixed the problem. Also it is real easy to put the switch in upside down, which was why I had the wires in the wrong place to start with. I would check this out thoroughly before I tore into my tank. Good luck.

Jimmy

[Eugene B.]

Re: C1 Gas gage reading is inaccurate

Gents,
There is a good article about C1 fuel gauge/sender problems in the December 2004 issue of the Corvette Enthusiast magazine. It is in the section called techbench and the author is John Hinckley.

Hope you find it interesting.

Regards,
Gene

[Dennis A.]

Great Article . . . *NM*