Technical Doblo 1.9cc 2013 Diesel Gauge always showing full

[UFONED]

FIAT DOBLO DIESEL 1.9cc 2013

We filled right up to max with diesel a few weeks ago now, and we have done several journeys since; but the fuel gauge keeps showing full. I guess we have done approx 150 miles since filling up. The needle drops when I turn off the engine, and hits the full level when I turn on the engine. Its not an area I am femalia with, so am hoping it can be simply resolved. Seen videos on how these things work on other vehicles but not on the Doblo. I am hoping someone has the answer and also what Ω values are needed and where to access the wiring to achieve the information.
Its a 1.9cc converted Doblo back in 2013 to an ambulance. I had heard that when they do these conversions the fuel tank is changed (but that is on hear say)? And now its a camper van.

 

[Greasytrucker]

Have you just bought this or do you know the gauge has only just started doing this? I’ve have numerous vehicles that if you brim the tank they take a couple of hundred miles to come off the full. Might just be how the gauge is on that particular vehicle

 

[UFONED]

Have you just bought this or do you know the gauge has only just started doing this? I’ve have numerous vehicles that if you brim the tank they take a couple of hundred miles to come off the full. Might just be how the gauge is on that particular vehicle

Thank you for taking the time to reply. We have had the vehicle for a couple of years. More or less sat there most of the time, so we have used it for general running about to keep it going. Have to say the fridge is very handy in the hot summer to store the cold stuff. I do know it should be lower than stated, which is why I need the Ω settings and where the relevant wiring is situated. The Ω figures will tell me roughly the amount in there if the gauge is working. If the gauge is stuck which I am guessing it is, then I need to know how to change it or mend it.

 

[Greasytrucker]

My guess would be faulty sender unit on fuel tank as most issues I’ve had with fuel gauges over the years have been linked to these. Plenty of Doblo owners on here to tell to how to access relevant bits!