tonite i hooked my gauges up and seem to have a problem getting an egt reading. the light comes on so my power source is good. the probe in in the manifold. i have checked everything twice and am wondering why i am not getting a reading. the boost gauge works fine. when i turn the ignition off the needle drops below 0. and then when i start it goes to 0 but never moves? anyhelp or ideas would be appreciated. autometer phantom btw.
thanks

 

It seems like my EGT gauge did something funky like that when the braided sheathing was shorting the signal out. Also, are you certain the polarity is correct?

 

i havent cheked that. i will. wait how would i check that?

 

On mine the wires were color coded and the little booster box was marked for polarity.

 

mine doesnt have a booster box, its all screws into the back of the gauge

 

Much smarter design than my autometer, but I'd think polarity still matters.

 

I may be telling you something you already know, but the EGT probe wires connect to a thermocouple at the tip. The wires are color coded because they are both made out of a different material. When temp rises/lowers, the difference in material composition creates a potential difference between the two, usually in the millivolt range. Anyways, you must be careful when installing to not break the wires. They are usually a small guage and because of their composition, more brittle than standard tin plated copper wire. Check your wires!

Also, polarity does matter, greatly. Also, be careful if you are using a gauge and a thermocouple that didn't come as a matched set. If you have pulled a guage from here and a probe from there, they could be very incompatible. There are many types, J, K, ....... difference being the material composition of the two conductors. Each gauge is set up and expecting to see a certain probe.

Working with millivolt ranges, it sure doens't take much to short them out. Always use grommets around sharp corners and through the firewall.

Let me know if you don't get it.