Fuel gauge

[TBG]

My fuel guage has started to wildly flicker from just below full until it reaches half full and then settles down,any ideas? D

[nmauduit]

voltage instability (check your instruments 10V voltage stabilizer - easier said than done I know), which can be increased from mechanical vibrations if it is a original one (vibratory stabilizer) - I suppose this happens only when the engine runs...

[oldelanman]

If it works correctly when the fuel tank is below 1/2 full then I think that rules out a problem with either the voltage stabiliser or the gauge itself ... more likely to be the sender unit worn out I would say.

[nmauduit]

If it works correctly when the fuel tank is below 1/2 full then I think that rules out a problem with either the voltage stabiliser or the gauge itself ... more likely to be the sender unit worn out I would say.

I would I thought that too, but considering the mechanical voltage stabilizer operation is load dependent (and fuel gauge current varies quite a bit between full and empty) I'm not so sure (also the frequency at which the gauge needle typically wiggles is quite high and steady in my experience, and would not easily reflect the wave frequencies in the tank - though a worn sender would not help proper operation of course). I suspect this may have to do with a harmonic frequency match between the stabilizer and the gauge at some point, enhanced within a certain range (and possibly with engine vibrations)...

[TonyA]

I had problems with erratic fuel level indication: turned out the float was perforated and half full of fuel, so wasn't swimming on the fuel as it should: Replacement floats are available but I stupidly shelled out 70 quid for a complete guage..! TOP TIP: take it out and check it mechanically and electrically before rushing out to replace...Tony

[Andy8421]

My fuel guage has started to wildly flicker from just below full until it reaches half full and then settles down,any ideas? D

If the gauge is flicking wildly, then it isn't the later thermoelectric type and doesn't have a voltage stabiliser, so ignore comments about that.

With the Elan's hopeless wiring, about anything is possible, but if the gauge is OK below half full, then the most likely component at fault will be the sender. There are two types, make sure you get the correct one.