Fuel Guage Intermittent Fault - Vitesse Mk2

[Paul H]

Fuel Gauge slowly  goes from say 1/2 full , to reserve or empty . All very graceful indicating im dropping fuel everywhere and initially very disconcerting !! . After a period of time say 10 mins its climbs back up but not to correct reading , goes back down again , then climbs back to normal . This doesnt happen on short journeys and generally after 20 miles . Because of the graceful way the needle drops I dont think its a cable issue - In the last 300 miles its only happened twice 

Incidentally the temp guage is an aftermarket  and works fine 

Any ideas 

Paul 

 

Edited September 18, 2017 by Paul H
added text re temp guage

[Pete Lewis]

check the sender earths on the tank

check the output from the voltage stabiliser,    check its earthed ok on the speedo 

its normal for the needles to move slowly . as the are damped by the bi metal operating spring, any break in supply gives a quietly descending needle 

the sender may also have a fault  in its windings , when the tanks low remove it and test the readings with a multi meter set on resistance