My passenger side gas tank had a high side pinhole leak in it, so I pulled the gas tank and fixed the leak.
Now, both tanks register full although both are slightly less than half full.
I have replaced my fuel gage with a known good one and the problem persists.
I also used a spare fuel sender and connected directly to my fuel gage, bypassing the fuel selector switch. Same result. The fuel gage reads full at all times, even as I move the sender arm up and down.
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Do the fuel gauge go to full when the ign is turned ‘on’ irrespective of switch position, David - and with both fuel senders disconnected…?
Have you checked resistances on the tank units with wires disconnected? Did you ensure that the spare fuel sender’s resistance did indeed vary as the sender arm was moved. Indeed, does the gauge show ‘zero’ when it is disconnected…? Did you do anything to the set-up apart from plugging in the replaced tank’s sender - and was everything working correctly before…?
As the gauge requires ground to show anything - showing ‘full’ means it is directly grounded…somewhere. The changeover switch just switches between two separate wires to the tank units - and cannot cause a ground fault when disconnected from the gauge…
Unless all senders are faulty, this is an the electricky problem - hence all the questions…
Electricky. The adjective form to describe wires in Jaguars.
Electrickery: The noun used for the process in Jaguars wiring.
The wires in my car continue to educate yet confound me.
The sensor in the tank is a basic electrical device. A variable potentiometer. Provides a ground leg that is progressive or linear. I’ve not looked at mine,
The way to test one removed from the tank is done with a power source and a VOM or merely with a VOM.
1 . Provide 1v to one side and ground to the other. Sweep by moving he float. measure volts in as to volts out,
Or merely use the resistance feature of the VOM. Repeat, sans power. Ohms at one position move and see if the ohms change. .
And, of course a careful visual inspection for breaks in the winding.
See Jaguar publication S57. The great schematic. Trace the wires from sensor to guage. An unwanted ground along the way?
A very long wire from the sensor to the guage jumping the car circuitry. Any better response?
