Fuel Gauge Issue

[bmiller269]

I've been trying to figure out a fuel gauge issue can someone that may have had this issue give me some help? The issue is that all of a sudden BOTH gauges read full when you turn the panel on. In flight sometimes one or the other gauge will slowly show a proper reading, but then go back to full pin pegged. I thought it was a ground issue but have ran a test wire to the ground terminal with no change. Someone told me it was the sending unit but both at the same time. Seems Unlikely. Any Help Thanks

 

[rvbuilder2002]

Some additional info would be helpful


What are you using for fuel gauges, what type of level sensors, etc. ?

 

[bmiller269]

They are van's gauges and sending units are probably what van's sold as the builder got everything form them.

 

[rvbuilder2002]

The senders have a resistance of about 240 ohms when the tank is empty and about 30 ohms when it is full.

So if the sensor wire for the gauge is shorting out to ground it would make the gauge read full.

I would start by inspecting the full length of the sensor wires and looking for anyplace they could be intermittently shorting out.

 

[BobTurner]

The one thing two gauges share is probably the power source. Most likely there is a single wire from a power source which is then split into two bias resistors, each feeding one fuel sensor. I'd check for a bad connection on the power wire. If it's open the gauges will read full. Also check that there is in fact voltage on that wire when the master is on.

 

[bmiller269]

OK I'll check some of this out tonight. Thanks For some Ideas.