Strange board temp reading

[M-Tech]

I noticed today that my board temp reading is 135c, this isn't normal.
Last night it was OK (reading ~20c).

What could have happened and how can I fix this?

Tried to reload the firmware but it didn't help.
If I remember, when I updated the firmware for the first time, the display went blank.
Now when reloaded the firmware it displayed  = (upper display) and Y (lower display).

And also when I select lower display to display EGT Celsius it still displays board temp in Fahrenheit.
And when I select board temp F it displays EGT C and the reading is off by as much as the board temp reading is off (showing wrong).

AFR seems to show normal values.

[rob@vems.co.uk]

Are you setting these display settings using MegaTune?

[M-Tech]

I used MegaTune and also the button on the gauge.
When I start the gauge with default settings (up - afr, down - board temp c) and press the button on gauge,
then it shows me egt c as I suppose from the reading.

[M-Tech]

Today when I was driving home from work, it did go back to normal reading for one or two ignition key cycles (on-->driving-->off).

[rob@vems.co.uk]

Really strange...  Let me know if it goes wrong again.

[M-Tech]

After these two ignition cycles it went back to the same wrong reading.

[rob@vems.co.uk]

Are your EGT wires touching together?  If not twist the two together to form a thermocouple junction.
If this doesnt work then it could be a noise issue, which we'll move onto later.

[M-Tech]

I'm always twisting the wires together when I'm not using the EGT sensor.
I don't like to see the maximum temp reading while the wires are not twisted.
And I also supposed it would  be good idea to twist the wires cause the sensor should be like a variable resistor.
Of course I'm isolating it from all other metal materials.

It's not the first AFresh gauge I'm installing and no other has had this kind of problems.

The gauge ground is connected directly to the engine and +12v is connected directly to the battery through a relay.
My MegaSquirt is connected to the same grounding points (all tough different wires and lugs) and no other problems have occurred.
I was using Innovate LC-1 before I bought the AFreshTiny and I had no problems with the LC-1.

I'm pretty convinced that ground and power connections should not be an issue.
Of course all connections are soldered not crimped.

[rob@vems.co.uk]

Probably best to report this issue to who ever you bought from and see about getting a replacement, giving the serial number of the unit.
Send them the link to this forum so they can see the bug and what we've tried to do to fix it.

Rob