Technical Grounding AutoMeter gas gauge

Installed an AutoMeter 2516 gas gauge along with an Attometer Fuel Level Sender 3262. Talked to Attometer and they said to change my 73/10 Hudson setup to a 240/33ohm sender and gauge to eliminate problems, but because of a difference of 6 hole tank and 5 hole gauge, I would need an adapter ring. Hooked up as per instructions along with aluminum adapter ring, even added a ground wire from one of the sending unit screws directly to the frame.....will not register higher than just above empty.
Changed wires, tested voltage and ohms, took unit out of tank and when grounded well, it read correctly at all levels while moving float by hand. Put it back in tank and it still won't read.
Seems like I need a better ground (maybe because of adapter ring ? )
Does anyone have a suggestion for getting a better ground?
Thanks

 

It sounds like your ground should be adequate. Is there a possibility that there is a baffle in your tank obstructing movement of the float ??

 

I second Geezer's idea.
Just a note on my experience:
On my 32 Ford, I installed all Autometer gauges. Great stuff.
When it came to the fuel gauge, it wouldn't work at all.
Took the tank back out. I had NOT installed a tank ground.
Called Autometer. Guy says hook up a ground wire to the
ground lug on the sender. I say there is no grounding lug.
He says sure there is. I send him a pic of my new sender.
He is amazed. No lug. They send me a new sender with lug.
Gauge now works well.
Everyone's happy. I got the only sender ever made without a
grounding lug. See, my luck is still holding....
Jim

 

The float is hitting anything inside the tank is it? I've seen the ones that go in from the rear where you can pull them out without dropping the tank, the senders are set up for the top access the float may not get full travel.

 

The tank has the sending unit hole in the front of the tank and the arm and lever of the unit go in at 45degrees. I can take it in and out through the hole without dropping the tank. The arm and float level extend inside toward the back, I bent everything to form an arc that would allow for the full/empty up/down action but I do have to admit that I don't know where the baffles are located inside.

 

Well, I checked the tank for baffles in the way of the float and there aren't any. I shortened the length of the arm and float rod anyway.....still won't read past 1/16th full

 

Ground is definitely my problem, I just can't get a good ground at the tank, I guess.

 

try running a temp ground from the sender itself to the negative batt post

 

Remove sender and solder a wire to the surface of the flange then connect the other end of wire to the body or chassis (you do have good ground there ?). If that does not work you'll need to do what's said below and run a dedicated ground. Also, is your gauge grounded correctly ?