fuel sending unit? or fuel gauge?-gctid362384

[Guest]

when i turn the key my gauge jumps to full no matter how much gas i have the float on the unit is free and moving. i took out the unit and moved float up and down but gauge stayed at full so to me that says the sending unit is jacked up. Right? just need someones thoughts on it

[boatworkfl]

hicklife wrote:
when i turn the key my gauge jumps to full no matter how much gas i have the float on the unit is free and moving. i took out the unit and moved float up and down but gauge stayed at full so to me that says the sending unit is jacked up. Right? just need someones thoughts on it

Check your elec. connections, especially the ground.

[SuperiorDiver]

With the ignition on, remove the wire from the sending unit to the gauge. It will indicate either full or empty. Now ground the wire at the gauge. The gauge should indicate the opposite. If it does, the issue is the sending unit.

[2850Bounty]

The in-tank fuel sender is creating a variable resistance to negative. This is what gives the instrument it's value.

When you test the fuel gauge, use a test light to create the path to negative so that you do not damage the instrument.

Or if you can find a variable potentiometer of the correct value, you could use that.

You could even use another fuel tank sender outside of the fuel tank, completely circumventing the sender currently installed.

Connect it up, and raise/lower the float arm.

This should tell you if the gauge itself is working correctly or not.

Do NOT do any testing of any kind in/around an open fuel tank sender port!

[Guest]

I was getting false readings on both of my gauges. Turned out that the floats on the sending units were no longer floating! Swapped out both sender units and all is well.

[Guest]

thanks for the help it was the sending unit!