Gas gauge doesn't work

[Paul S.]

I am finishing a restoration on a 1966 . I have already installed a new tank and sending unit. As soon as i turn the key on the gauge goes to full ( tank is almost empty).i did not replace dash harness or rear harness or the gauge . One other note , as soon as i take the ground off at the tank the gauge does go down , but not to the proper level . What do you think ? Gauge ? Wiring ?

[Richard G.]

Re: Gas guage dorsnt work

I had the same goofy readings issue. It turned out to be the tank sensor.
The China manufactured gauge, I purchased, had the wiring pinched and shorted to the cover. Right where the wire entered under the cover it had not been positioned correctly at the slot when the cover was crimped on. This shorted the wire to ground.

The resistance between the terminals at the tank should be about 90 ohms full and with an empty tank the float is down and the meter drops to between 3 and 0 Ω.

There is a nice article called:
Inside the mid-year fuel gauge and sending unit
With Photos by Tim Welsh (Buns) and Dave Zuberer (DZVette) Diagrams by Tim Welsh and John Hinckley (JohnZ).

If you can get a copy it will help you fault find the system.
Rick

[Michael J.]

Re: Gas guage dorsnt work

Here's a link to get the article Rick mentioned: This is the article, but don't download anything.
https://studylib.net/doc/18310128/mi...d-sending-unit

Here is another good one:

http://www.ncrsmac.org/garage/Wiring%20and%20Bench%20Testing%20the%20Mid-Year%20Corvette%20Instrument%20Cluster%20-%20Zuberer%20&%20Welsh%20-%20rev%205-19-2.pdf