Pyrometers malfunction

[dordtrecht5]

I'm needing some help with my pyrometer. I have a Hewitt Industries pyrometer and it was working up until a couple of days ago. I haven't taken it out to check anything yet, but this what the deal is: the gauge will barely register anything until the truck gets some solid egts, around half throttle for a bit so it would be around 600-700 degrees. It will pop up to 500 and then start falling to about 300. It won't go above 600 degrees. When I accelerate it will climb very slowly, but then fall if it's just part throttle. At full throttle it will only push the needle backward.

Does anybody have any clue as to what is going on with this thing? Do I need to buy another?

 

[BlkMax]

It may be a bad thermocouple. You could try putting a volt meter on the leads and see if you get a steady voltage increase as the temps would normally increase. If you get nothing, or it is erratic, then you probably need a new sensor.

If you do an internet search, you can probably find the correlation between the output voltage and the temperature for a type K thermocouple (what is probably used for your sensor).

 

[baggedLB7]

My edge probe has done this twice to me in a year now and I changed the probe ea time and it fixed it for me.

 

[dordtrecht5]

Ok. I appreciate the input. Time for a new probe then.