MG Car Repair: gas gauge, gas gauge, earth ground

Question
Barrie,

My gas gauge doesn't work or is incorrect most of the time!
Could this be caused by a faulty sending unit in the gas tank? How can I test the system to find my problem? (1977 MGB)

thanks in advance

pete

Answer
Hi Pete
If the gas gauge does not read at all, then you probably have a minor wiring fault.  If the gauge only reads some of the time then the sender inside the tank has failed and you need to fit a new sender.  Try removing the wire from the sender and touching it to earth (ground).  The gauge should shoot up to the full mark almost immediately, proving that there is nothing wrong with the wiring.