fuel sending unit help

[garyt]

i am trying to figure out the wiring to a 1951 chevy truck. ok I have converted over to 12 volts on my truck I have a rci fuel cell with the sending unit in the cell, I connected the sender wire to my newly rebuilt gauge on the terminal marked sender I then connected the 12 volt wire from the ignition to the other terminal on the gauge, I then grounded the sender as suggested to the frame. I get backward movement when I lift the float and its very very little movement on the gauge. what did I do wrong, anyone got a schematic for a dummy or an idea what I did wrong. I think I have 90ohm sender and 90 ohm gauge

[1project2many]

Well, you maybe didn't do anything wrong. First thing though, double check that the body of the sender is properly grounded. Check resistance to ground or use a test light connected to B+ and try to ground it at the sender body. No light probably means no ground. If the sender's properly grounded, test the gauge. Disconnect the sender wire and see if the gauge goes above full. Ground the sender wire and see if the gauge goes to empty. If you don't get the right results you'd better question the gauge and the 12V wire that's attached.

If gauge is ok then do a simple test of the sender. Connect one end of test light to battery + and the other end to the terminal on the sender. Then ground sender body and move float arm. Light should get brighter as arm gets near empty. Make sure to use a test light with a regular bulb, not an LED.

[_Ogre]

if you have a multi meter do the same tests as 1p2m suggests for the sender
should read 0 at empty and 1 at full with a smooth run from empty to full

for the gauge use a jumper wire to ground the sender terminal the gauge should read empty
reverse the ignition wire to the sender terminal and do the same test, it may be wired backwards
also make sure your ignition wire is 12v

[garyt]

thanks guys will try all that you have suggested tomorrow, much appreciated on some direction to my problem, again thanks

[solidaxel]

Is the float arm attached to the movement with a screw.
You may have to move the arm to the other side of the movement so it reads 90 to 0.
I hope that makes sense, if you can get the needle to move the problem is with the tank sender