Fuel gauge issues.

[sogood]

Mentioned this before but still no resolution. My fuel gauge pegs full when I switch on the ignition. It's a new Faria gauge and it does this even when the sender is totally disconnected.
I've checked for shorts etc and all the relevant wiring checks out fine. The gauge replaces an old non functioning gauge. It seemed to be stuck on half full. I went with Faria to match the other gauges on my boat. Any thoughts appreciated.

 

[jhebert]

Check the negative circuit path for an open somewhere.

Is the gauge illumination circuit activated?

 

[Scott Danforth]

there are four wires to connect to a fuel gauge.

I = ignition and is a purple wire
S = sensor and is a pink wire
GND = ground and is a black wire
L = lamp and is a blue wire

 

[alldodge]

Mentioned this before but still no resolution. My fuel gauge pegs full when I switch on the ignition. It's a new Faria gauge and it does this even when the sender is totally disconnected.
I've checked for shorts etc and all the relevant wiring checks out fine. The gauge replaces an old non functioning gauge. It seemed to be stuck on half full. I went with Faria to match the other gauges on my boat. Any thoughts appreciated.

Disconnect the pink sender wire from the back of the gauge, it should not move from empty.

If it does let us know

 

[Fed]

Disconnect the pink sender wire from the back of the gauge, it should not move from empty.

Unless it's a European gauge.
I got caught out by one that was fitted to a boat I bought & no amount of swapping wires can fix it.

 

[sogood]

Thanks for the input guys. I think the last poster might be near the mark. From the various suggestions I was given, I did the following; Ran a new (temp) ground from the gauge. Result, still pegging full. With the ground disconnected, the gauge doesn't move. Disconnected the Pink sender wire at the gauge. Result, gauge pegs full. Ran in a new (temp) pink sender from sender unit to gauge. Result, still pegs full. Disconnected the pink sender wire at sender. Result, still pegs full. Disconnected the ground at the tank/sender. Result, still pegs full. For what it's worth, there is no continuity between the black ground at the sender unit and the green wire connected to a tab on the top of the tank. I cleaned up this green wire connection, which was dubious and bolted it down good and tight. No change.

​Then I removed the sender and found that it worked, but in reverse! So that when the tank is empty, as it is now, it reads full, but when I move the float/arm through its' movement, the gauge reads empty. Likewise for all points in between. So, could I have the wrong sender for the new gauge? The sender is definitely connected up correctly, spade connector on black ground and pink sender wire connected to the threaded post .Given that the boat is American, but now living in Ireland, where I sourced my (European) Faria gauge, might I have an incompatibility issue? It's all that I can think of now. Any thought much appreciated.

 

[alldodge]

Either need another sender or another gauge. Might try to get a US standard gauge because the rest of you gauges work that way. In any case no matter which way you go it will work without issue.

 

[sogood]

Looks like it will be a new sender so. The gauge is new.

 

[Fed]

Here's a little chart for any other gauge problems you may come across.
Note the reverse function of the OMC Vs Mercury trim gauges, the boat I bought had a motor change so at the time I had 2 gauges working in reverse so that led me along the path of wiring problems. I should have realized the PO was an idiot.

 

[sogood]

My replacement sender arrived yesterday and I fitted it today and now all is working as it should. Thanks for the responses and input.