Gauge problem

[Johncracknell]

My fuel gauge under reads and the temperature gauge over reads, I think they both played up about the same time, anybody have any clues ?

[foster461]

My fuel gauge under reads and the temperature gauge over reads, I think they both played up about the same time, anybody have any clues ?

 

Both of those instruments rely on a working voltage stabilizer, the widget that is attached to the rear of the speedo.

 

Stan

[Stoker]

Hi John

 

I think you will find it is your voltage stabiliser which is screwed to the back of the speedo so I'm afraid it means removing the speedo to replace

I have just done mine and got a very nice solid state one on e bay for £8

 

John

[john.r.davies]

Both gauges work the same way, they run the currant from the sensor through a bimetallic strip, which heats, bends and moves the needle.

If they get too much current, they overread and vice versa.

The volts stabiliser supplies both, so if one is overreading and other under, then it's NOT the stabiliser!

 

An underreading fuel gauge is either:

fuel in float - there's a hole in it.

Stuck float arm - gauge cannot move the rheostat over full range

Rheostat windings worn/corroded

 

,The temp gauge is a thermistor, an solid state electronic device whose resistance changes with temperature. In Triumphs it goes down as the heat rises, but they can. especially modern repros , go off and give wildly inaccurate readings.

 

Inspect the first - you will need a new gasket for the tank afterwards

get a new temp sensor - cheap as chips, and may only last that long.

 

John

[foster461]

John is correct, there is a big difference between failed at the same time which would point to a component they have in common and failed about the same time which could just be coincidence. What does the temp gauge read if you pull the wire of the temp sender and ground it ?

 

Stan