Gas tank sending unit

[Guest Chris Becker]

Hello!

I'm a first time user and have a question about getting my gas gauge to work properly. I installed a new sending unit in my 51 Dodge pickup, put in six gallons of gas, and the gauge reads "full." Is there something else I need to do to get the gauge to work properly?

[bob westphal]

How did it read before you installed the new unit? Do you have two wires or one on the sender? If so, they could be bacwards. Or you could have the wire shorted out. What does the gauge read with the sender wires unhooked?

[norrism1]

Chris. With the sending unit out and connected to a 6 volt source and Ohm meter. The reading at "empty" should be 10 ohms and at "full" it should read 90 ohms.

[Plymouthy Adams]

Do not use ohm scale with voltage applied..spell this fried meter

Using volt/ohm meter you can check for continunity between the input and base of the sending unit,(ground) and while in ohm mode (no power applied) there should be as he states 10 ohms at one end and about 90 ohms at the other with a smooth changing across the scale as you go from one end to the other...this checks out only the sending unit...to check your guage, you can do it two ways..ignition on disconnect your wire at the sender..guage will read zero..ground your wire and watch to see if the needle will start to rise..if it does, remove from ground at about 3/4 mark to allow it to cool off..this check both the wire and the guage.. the other method is to connect a 10 ohm resistor to ground and read scale with ignition on...connect 90 ohm resistor to ground and read scale..should be full deflection. If neither of the test shows anything you may have an open wire between the gauge and sender or bad ground at the tank..repeat test with a jumper wire to a good known ground..

report your findings...

[norrism1]

Chris,

Sorry for the mis-information about the voltage with the ohm meter. I have GOT to think about it and preview before I hit the submit reply.

Tim, Thanks for catching my scew up.

Norris