Calibrating gas gauge to sending unit 1967

[Al R.]

Is there an easy way to calibrate the gas gauge to the fuel sending unit on a 67? I've checked the archives to no avail. Gauge was cleaned and checked when the cluster was restored by a well known restorer. The original sending unit was also rebuilt by a well known highly recommended restorer. New gas tank and wiring harness. The gauge just will not register FULL when the tank is full. It only goes to 3/4. Need it to work correctly. Not sure what it will read when empty. I did see where you could short out the wires individually at the sending unit to make the gauge read full or empty, but is this the way to eliminate either the gauge or the sender as the culprit or a way to actually calibrate the two. The restorer that rebuilt the sender did tell me he calibrated it for the 0-90 ohm settings.

[Keith B.]

Re: Calibrating gas gauge to sending unit 1967

Sent PM. Need help with this as well

[Al R.]

Re: Calibrating gas gauge to sending unit 1967

I plan to call the sender restorer tomorrow to see if he has any suggestions. One problem--the work was done in Jan. 2012, but car was not completed until May 2014. It was not filled completely until last weekend. Still working out the bugs on her. Work schedule does not permit as much time as needed. Hopefully only 2 issues remain with her, other than the fuel gauge. Will get there one day!! Maybe!!!

[Neal K.]

Re: Calibrating gas gauge to sending unit 1967

I have a similar issue. Recent rebuild of sending unit and gauges on my 67. Fuel gauge indicates just below quarter of a tank of fuel but tank ran dry on my way to the gas station before I realized the gauge was not reading correctly. Please post what you find out as it will likely be of help to others.

[Ken A.]

Re: Calibrating gas gauge to sending unit 1967

Sender should read 0 to 110 ohms for gas gauge to read properly on a C-2. If not replace sender.

[Rick A.]

Re: Calibrating gas gauge to sending unit 1967

agree with Ken - also, make sure to check GROUND as many times this is the bane of the problem with the gas gauge

[Larry M.]

Re: Calibrating gas gauge to sending unit 1967

Sender should read 0 to 110 ohms for gas gauge to read properly on a C-2. If not replace sender.

Ken:

How did we get the number of 110 ohms?? Every article I have read over the years indicates that for the C2 cars this resistance is 0-90 ohms.

My 1967 car (26,000 miles) gas sender read 0-90 ohms when I pulled and replaced the gas tank a few years back. Gas gage still reads correctly at 1/4 and 1/2 and at full.

Need some help understanding this.

Larry

[Ken A.]

Re: Calibrating gas gauge to sending unit 1967

GM revised specs due to numerous complaints of "less than full" readings over the C-2's life span. Senders were revised again for the C-3's & the C-2 sender was deemed a failure by GM. If you still have an old sender, note that ethanol is eating it up as we talk. Zip & LI sell the new GM approved sender. Just because you read otherwise, doesn't make it so. Remember, the internet is 60% false.

[Leif A.]

Re: Calibrating gas gauge to sending unit 1967

Remember, the internet is 60% false. 100% of the time.

[Edward B.]

Re: Calibrating gas gauge to sending unit 1967

With the sending unit removed from the tank check that movement of the float arm through its complete arc corresponds to a swing from "full" to "empty" on the gauge. If so, it is possible that the float when installed in the tank is reaching the upper limit of its travel before the contact at the other end of the float arm gets to the "full" position on the resistor winding. Bending the float arm downward should allow for a proper range of motion for the contact point. Of course, bending the rod too much will result in the float bottoming out before "empty" point is reached on the resistor winding. This adjustment may take several tries before "full" and empty" read properly on the gauge.

[Larry M.]

Re: Calibrating gas gauge to sending unit 1967

GM revised specs due to numerous complaints of "less than full" readings over the C-2's life span. Senders were revised again for the C-3's & the C-2 sender was deemed a failure by GM. If you still have an old sender, note that ethanol is eating it up as we talk. Zip & LI sell the new GM approved sender. Just because you read otherwise, doesn't make it so. Remember, the internet is 60% false.

[Al R.]

Re: Calibrating gas gauge to sending unit 1967

Mine also runs on non-ethanol. I did not have time today to contact the sender rebuilder. Tomorrow may be worse time wise, but hopefully , I'll be able to call by Fri. will also try to ground out the wires this weekend to check that phase. I was also contacted by 1 other member on this site that has the same problem w 3/4 registering when the tank is full that had his sending unit rebuilt by the same person. Co-incidence, by chance ----ORRR?

[Keith B.]

Re: Calibrating gas gauge to sending unit 1967

I'm having the same trouble and have checked the ground and other trouble shooting methods. Still haven't solved it. Due to time restraints I have yet to contact the rebuilder of the sending unit.

[Jim D.]

Re: Calibrating gas gauge to sending unit 1967

If you still have an old sender, note that ethanol is eating it up as we talk. Just because you read otherwise, doesn't make it so. Remember, the internet is 60% false.

In the case of ethanol caused problems, I'd up that number to around 100%.
Why not say who restored your sending unit? Mine for my 65 was restored by John Wolf. I used ethanol gas and it read full when full, empty when empty and was accurate in between the two. I don't know if he restored its resistance to 0-90 or 0-110. Regardless, another B.S. post about ethanol causing problems.
Come to think of it, my wife came down with a nasty cold yesterday and I had just filled the tank with more ethanol poison. I'll bet there's some out there that think the two are related.

[Donald H.]

Re: Calibrating gas gauge to sending unit 1967

I have attached a John Hinckley article that I had in my file. It give a technique to check the gauge function.

Don