wandr
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| posted on 16/11/17 at 10:47 PM |
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Digital water gauge problem
Hi all , I have fitted a simoni digital water temperature gauge and have a strange problem that the gauge reads 40 degrees when the engine is stone
cold, demon tweeks have told me they think it is an issue with the sender and said put PTFE tape around the thread, this has not worked sender is
brand new, earth for the gauge is good and it is wired to live ok, when I disconnected the sender wire completely it still read 40 degrees, any one
have any ideas?
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ian locostzx9rc2
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| posted on 17/11/17 at 07:26 AM |
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Faulty gauge I guess
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coyoteboy
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| posted on 17/11/17 at 07:51 AM |
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What did they hope ptfe tape would do?
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ian locostzx9rc2
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| posted on 17/11/17 at 08:05 AM |
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That’s a mystery!
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pekwah1
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| posted on 17/11/17 at 09:39 AM |
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My digital temp gauge (not a simoni) is identical, seems to have a minimum reading of 40 degrees also.
It doesn't really bother me to be honest, works perfectly well otherwise
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MikeR
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| posted on 17/11/17 at 11:30 AM |
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absolute guess here but ...
The gauge is reading a resistance value from the sender. Either the sender base / starting resistance is the same as 40 degrees OR the gauge
doesn't do any values below 40 degrees.
Is it really a problem?
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coyoteboy
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| posted on 17/11/17 at 12:47 PM |
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Often they'll match the curve to the operational range so you get better accuracy at that location, at the sacrifice of the extremes you
don't care about. So it is distinctly likely it's just how it's meant to work. But if it's a matching gauge you'd expect
that to have no readings below 40C just so customers don't ask!
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ian locostzx9rc2
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| posted on 17/11/17 at 01:00 PM |
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Seems a rubbish if it starts at 40 degs but I guess as long as it’s accurate when you want it to be that’s the most important thing .
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David Jenkins
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| posted on 17/11/17 at 02:20 PM |
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I think PTFE tape could stop it working, if the temp sender uses the engine block as the earth return. It's a vague chance, but I'd only
use PTFE if there were any signs of water leaks.
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wandr
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| posted on 17/11/17 at 03:12 PM |
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Hi all, the PTFE tape was suggested by Demon tweeks as they thought there might be an poor earth path from the sender but it does it with or without
so maybe it's just meant to start at 40, doesn't really matter I guess, by the sound of some posts I might get another and it will be
exactly the same, I
haven't used digital before so I was assuming that they would all start at zero like standard gauge types, many thanks as always for all your
help and replies
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02GF74
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| posted on 17/11/17 at 06:48 PM |
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Most gauges aren't marked and you assume that when the needle is at the minimum position that represents 0 degrees. I'll bet it does
not.
Also the water temperature when the needle starts to move is probably well above 0.
If the gauge shows correct temperature when engine has warmed up I. E. Thermostat has opened, it is working correctly.
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dmrider_10
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| posted on 5/12/17 at 06:32 PM |
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Just for info, I have a different type of digi temp gauge and it operates the same from 40 degrees plus
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CosKev3
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| posted on 5/12/17 at 07:51 PM |
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Yeah most cars coolant gauges minimum reading is 50 degrees,if you plug diagnostics in you will see the true temp,and the gauge starts to rise at 50
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SteveWalker
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| posted on 5/12/17 at 09:20 PM |
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quote:
Originally posted by CosKev3
Yeah most cars coolant gauges minimum reading is 50 degrees,if you plug diagnostics in you will see the true temp,and the gauge starts to rise at 50
On lots of cars you can enter a test mode without any diagnostic equipment and get a display of all sorts of readings. I have used this on various
vehicles to see the water temperature, voltage, litres remaining and much else. On one car, using the odometer to display speed in kph - as the
secondary red markings on a black background were unreadable in sunlight.
For instance, holding the trip-meter reset button while turning the ignition on on a Ford Focus goes into test mode and each press advances the
function (gauge sweep test, warning lamps, software version, battery voltage, water temperature, etc.) all displayed on the odometer LCD. While
pressing and holding BC until it beeps on a Vauxhall Zafira changes the radio display to show multiple items of information and other buttons move
between the screens.
I'm sure most cars have hidden features like this.
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