TR2/3/3A TR3 gas gage

[Deleted member 451]

My 59 TR3 gas gage reads full at anythng over 1/2 tank. What is strange is that it goes from 1/2 to full all at once and returns the same way. It's not a big deal just annoying.
Any Ideas? /ubbthreads/images/graemlins/crazyeyes.gif

 

[martx-5]

The float assembly in the gas tank could be the culprit. It's a variable resistor, so remove it and check with an ohmeter and see if the same thing happens as you move the float arm.

 

[Geo Hahn]

Mine was similar. The sending unit was okay, but one of the fine wires in the gauge had broken disabling one of the 2 side magnet coils that work in competition to move the needle.

I would have been shopping for a new gauge but instead found these fabulous pages that detail the diagnosis, disassembly, repair, assembly and calbration of the gauge. It's for an MGA but that's essentially the same gauge as the TR3.

https://mgaguru.com/mgtech/electric/fg_01.htm

I didn't build the elaborate tester but did pick up enough of an assortment of resistors to jury-rig the resistance for the variuos levels. Now my gauge is perfect.