Fuel Gauge Reading

I finally got around to wiring up my fuel gauge. It’s a stand alone 2” gauge. Brand is equus. Sender is brand new. Crown or omix, i can’t recall which.

I know everything is working, as I had about 5 gallons in my 10 gallon tank and the needle on the gauge was right in the middle. Then I filled the tank and the needle went all the way to full.

so here’s the issue. I’ve driven 25 miles since filling up, and the gauge is still pinned at “full.” The bobber on the tank sender isn’t visible when I look down the filler neck, so I assume it just takes a few gallons for it to start moving downward and sending a signal to the gauge. Is that normal?

 

I have same setup and although I haven’t had it rolling yet I have ran it for a while and am curious about accuracy too. Looking forward to hearing from others.

 

I have the Omix sender in my '69 with the stock gauge and see the same behavior. When full, it takes a while to move. Mid and empty seem reasonably close.

 

Did you match the sender to the gauge as per the ohms that it reads at?

 

gauge is equus 7361 - Range: Empty = 73 Ohm, Full = 10 Ohm

sender is crown j0914850 - Empty 70-80 ohms, full 8.5-10.5 ohms

 

Measure the resistance to ground and see if it has changed. The gauge won't move unless the resistance of the sender changes.

You can adjust these senders by bending the rod and/or moving the stops. Use your multimeter and follow the changes. You can also test the response of the gauge with fixed resistors. Each value is less than 10c at Mouser or Digikey. Add clip leads and you have a tester.

I bought these a while back - https://www.amazon.com/gp/product/B07SB14WPZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 They are fine. Likely you can get them for half as much on eBay if you'll wait for them to ship from China.



Build A Gauge Tester

 

I'd also guess that the float sits right on the surface. If you fill the tank completely, the level will have to drop about the height of the float to see any change. Measure the tank and you can get an estimate of the volume drop needed to see any change.

 

Did you ground your Tank? I ran a wire from a sender screw to a known ground, and it fixed mine. Mine has 4 gallons when it shows empty, seven gallons fills it back up. Good Luck.

 

I’ve been trying to drive the Jeep as much as possible to see what kind of mileage I’m getting. So far, I’ve gone 93 miles on this tank of gas (verified by gps) and the gauge is reading somewhere between 1/4 and 1/2 tank full. It took about 40 miles before the gauge moved below 100% full.

But even though the gauge isn’t 100% accurate, the good news is that I’m getting at least 10 miles per gallon. Probably closer to 13 or 14 mpg, which I’m plenty happy with. That’s better mileage than my TJ.

 

Seems like your gauge is pretty accurate, or close enough, and 13 to 14 mpg isn't bad either! I had a similar problem with my 3A years ago and had to fiddle with bending the arm a couple times to get it close to accurate. The gauge in my stock '56 CJ5 is fairly accurate as well. I came to learn, the hard way, that once I get between E and about 1/8 of a tank I should fill up soon and stay off extended slopes where the remaining gas sloshes into a corner away from the fuel line outlet