Fuel gauge query...again

[MilesA]

Until the lower windings on my fuel sender broke, my fuel gauge was pretty accurate. I have now realised that the gauge is a later bi metal one (slow movement of the arm) with a butchered face from the magnetic version to accommodate the slightly different arm position. I had thought that these needed a voltage stabiliser to work accurately but have never seen one in my 3A.

 

Have I misunderstood this (that's entirely possible!)?

 

I have sourced a matching original sender and magnetic gauge (instant arm movement) so if a stabiliser is buried in the car wondered if it will interfere with the performance of these items.

 

Miles

[boxofbits]

Hi Miles

 

The stabiliser unit was normally installed at the back of the dashboard or bulkhead sides area, but if your guage had just two connections it's likely that a stabiliser was not fitted, as there was an extra connection on the guage for this.

 

Worth checking your circuit diagram in the WM just to confirm connections are as original spec.

 

Regards

 

Kevin

[RobH]

There are only two connection terminals on both types of gauge so you cannot tell by that.

 

The 3A did not have a stabiliser but it should be easy to check if one has been fitted by measuring the voltage at the fuel gauge supply wire. If the voltage is steady and equal to the battery voltage then there is no stabiliser. If a standard bimetallic type has been fitted the voltage will be varying at a regular rate. If a modern semiconductor type is fitted the voltage will be steady but a bit lower than battery voltage - around 10v.

 

I don't know what effect there would be running a magnetic gauge from a 10v supply; since the gauge is self-compensating for voltage it might work OK even though 10v is lower than the voltage it was designed for. It depends on what margin of adjustment is available.