67 Gas Guage/Sender.

[Richard S.]

Thanks to those who have provided previous help here I am making some slow progress. As of last night, with Guage and Tank Sender correctly hooked up, and the ignition key in the "on" position, I touched the "S" terminal on the back of the Guage with a grounded probe. The Guage needle moved from the 1/2 position, where it always stays when the Tank is more than half filled, to the 3/4 position. The Tank is 3/4 full now.
1)Should the needle have moved to the Full mark when I grounded the Guage even though the Tank is only 3/4 full?
2)Can I rule out the Guage as the problem?
3)As the Tank Sender is well grounded(twice),is the problem in the grounding of the Guage or in the wiring?
Any thoughts are,as always,very much appreciated.

[Bill Clupper]

Re: 67 Gas Guage/Sender.

The gauge itself does not rely on a ground in the IP. There is a yest procedure in the '63 Service manual that inplys you will get a "full" reading by grounding the brown wire (S terminal). If you do that and the gauge does not read full, replace the meter in the IP. With the tank empty, you should read from 87-93 ohms of resistance between the two terminals in the sender, and near zero with the tank full. Tis should let you figure which end of the car to look at.

[Richard S.]

Re: 67 Gas Guage/Sender.

Bill, I've done that test and a number of others as well.The tank is not empty and I can't empty it just now. When you say "meter" I take it this is the actual "guage" itself.....and "IP" is instrument panel. I'm grounding the "S" terminal but the "GUAGE" does not go to "full", it does however go to the "correct" position, which it did not before. Also throwing me off the track is the fact that just after the restoration was complete last summer the guage did work once or twice when I filled the tank.....then just started to show only 1/2 full when the tank was filled and worked fine from 1/2 full to empty. And I know the 63 service manual says this condition should be a bad ground at the Sender...but I've grounded it twice back there and still the problem.
Thanks for your help.

[Bill Clupper]

Re: 67 Gas Guage/Sender.

How are you grounding it? What do you mean by "correct" position? The only ground that is of any inportance is the one to the tab on the meter, from the wiring harness, Any other ground is useless in this system. What is the condition of the terminal in the wiring harness and is there any corrosion on the tab? There should be a noticable force required to seat the single connector on the tab. If the tank is full, or at 3/4 you can still measure the resistance and interpret liniarly the 0-to 90 ohm range to verify the tank unit and look for the corresponding reading on the IP gauge.

[Richard S.]

Re: 67 Gas Guage/Sender.

I'm grouding it as described in my first post...by touching a grounded probe to the connected "S" terminal on the back of the guage. The harness connection is connected to the "S" terminal as required and is tight. "Correct" position of the needle means the guage shows the tank is 3/4 filled, which the tank is.
Sorry for the confusion.

[Bill Clupper]

Re: 67 Gas Guage/Sender.

If you have access to a sensitive ohmmeter, I would check the resistance in the wire from each post on the tank to the same color wire on the IP wiring. The resistance should be about 1 ohm or less. If not, check for corrosion at the harness side of the tank connection, or in the Body to IP connector over by the Drivers side kick panel