Smiths temperature gauge

[Captain flint]

Just fitted a Smiths water temperature gauge,but can't get it to work!
I have shorted out the gauge through the sensor wire and get full deflection on the dial,
doe's this mean the gauge is O.K?
I checked out the sensor ,and reads around 1400 ohms cold and around 120ohms at boiling.
When sensor is put in cup of boiling water gauge does not move past 30 degrees centigrade
Really my main question is,do I need a compatable Smiths sensor,as the one fitted is an
unknown make.
Thanks for looking.
Martin.

[PAULJ]

Hi, the supply to the gauge needs to be a steady 9 v you take the power from the volt stabilizer that feeds the fuel gauge.
Mine packed up recently and I replaced it with this

http://www.ebay.co.uk/itm/281471438713? ... EBIDX%3AIT
Works a treat and will supply three gauges.

[Boomlander]

Quite correct, I had to fit a solid state voltage stabiliser to Jethro before the new temperature gauge would read correctly.

[bmcecosse]

But that's not the problem here - it is an incompatible sensor.....

[Trickydicky]

For anyone wanting to get busy with a soldering iron, here's a article on how to make your own voltage stabilizer.
http://www.britishv8.org/articles/mgb-v ... ilizer.htm

[alexmcguffie]

Your problem is the wrong sender for your guage. Whether you are supplying it from the voltage stabiliser is another question.

As for the solid state stabilisers (regulators) be very wary of them. They might work ok when driven from an alternator but there is a good chance they will go pop when driven from a dynamo. The one in trickydickys link has no input or output capacitors which a 7810 device should always have - even more so if supplied from a noisy voltage source.

[PAULJ]

Sorry mist the bit that said Im using a stabilizer. When my stabilizer failed the other week the fuel and water gauge was reading less than half what was expected

[bmcecosse]

That's odd - if it failed to 12 volts (instead of the regulated 10 volts) the readings should have gone UP not down.... Maybe it failed to give lower volts.. did you attempt to measure the output ?

[PAULJ]

No, was the wife's car. She came home one day and said she had just filled the car up with fuel and the gauge was reading half. Also she said the temp gauge was always on cold. I looked for a stabilizer but could only find land rover or mini ones that have a different mount. Then I saw the electronic one so thought Id give it a go. Works spot on. I cant see how a stabilizer would give a low voltage. Isn't it a by metallic strip that controls the voltage. it would have to speed up to reduce the voltage. Perhaps Im wrong. it happened once before.... I think

[bmcecosse]

Yes -that's what I think too - therefore it's likely to fail to 12 volts (contacts sticking IN) which would give high readings... or to fail completely with 0 volts.

[PAULJ]

If I haven't ditched it ill put 12v across it see what comes out. Anyway how's the bloke who submitted the original post getting on ????

[katy]

You may need to put a load on the output to get a proper reading.

[bmcecosse]

And not use a digital voltmeter.

[Captain flint]

Many thanks all,next step to get a proper Smiths sensor and tap
Into voltage regulator on rear of speedo.
Will let you know in the week.
Grateful for all the input as usual!
Martin.

[Theo_NL]

Just fitted a Smiths water temperature gauge,but can't get it to work!
I have shorted out the gauge through the sensor wire and get full deflection on the dial,
doe's this mean the gauge is O.K?
I checked out the sensor ,and reads around 1400 ohms cold and around 120ohms at boiling.
When sensor is put in cup of boiling water gauge does not move past 30 degrees centigrade
Really my main question is,do I need a compatable Smiths sensor,as the one fitted is an
unknown make.
Thanks for looking.
Martin.

I have the same problem, and as in this thread (and many others) was suggested: connect it to the voltage stabiliser. But...
I have a gold speedo, without voltage stabiliser. My fuel gauge is working properly (at least full = full and empty = really empty as I experienced last week again ). The gold speedo is probably not the original one (1965, with alternator, neg earth), it should be black? And do the black speedo have the voltage stabiliser?[frame][/frame]

[bmcecosse]

Yes! It's not part of the speedo- just happens to be a handy place to keep it - beside the fuel gauge.

[Theo_NL]

And the gold speedo does NOT have a voltage stabiliser?
So for the temp gauge i need to add one?

[bmcecosse]

Indeed - yes.

[mike.perry]

As long as the speedo has the correct TPM it does not matter what colour it is. 1504 speedos are available in gold (948 cars) and black (1098 LCV) and 1408 speedos are available in gold (early 1098 cars) and black (late 1098 cars)

[Theo_NL]

Thanks for the reply. I will have to order a voltage stabiliser for the temp gauge.

My temp sensor is giving 1400 Ohm when cold, and 70 Ohm when hot. The temp gauge however (connected to a 10V external supply) is still showing 35C with a resistor of 150 Ohm and approx 80 C with a resistor if 6 ohm. Are sensors available for this range?