Fuel Gauge Reads empty

[Hurls]

I recently purchased a 2013 F250 with duel fuel.(Westport Wing System) I bought it from a friend who had driven since new. The truck sat for 3 months before I purchased, and the CNG tank was empty when parked. The system worked before it was parked, I know because I test drove. I filled up with CNG and the CNG fuel gauge reads empty. The shutoff valve on the tank is open. I am guessing a communication problem or a filter problem? The truck is equipped with a toggle switch that can turn the CNG on and off. Could a short in the switch cause this?

Thank you very much.

[joe_kan]

I am not familiar with the Westport Wing System but the multitude of CNG vehicles I've owned over the years would seem to point to the high pressure part of the system either not getting fuel or the sensor for reading high pressure is either not working or has a wring issue. I'd measure the fuel pressure if possible and if this looks good then see what kind of signal you are getting from the pressure sensor. When you say the shutoff valve on tank is open - how do you know or is it a manual valve? The GFI electronic valves tend to stick if not used for a long time...