How to test an Exhaust Temperature Gauge - aka - Pyro EGT gauge

Author: Autobox  

Exhaust Temperature gauges are very easy to test to see if they are working correctly.

Maybe you wish to test it prior to installation, or you are having some issues after installation. 


1. On a work bench away from the vehicle connect the gauge up to a 12 volt source

2. Attach the temperature sensor (probe) to the gauge.

3. With a BBQ Gas Lighter heat the probe end - being careful not to burn yourself.

4. Within a minute the gauge should rise and the temperature on the gauge should read 4-500 degrees celcius

Testing an EGT Gauge

The temperature sensor does occassionally fail in a gauge but this is not often. The most common causes of an Exhaust Temperature gauge not working is wiring or incorrect installation.

If your gauge is erractically jumping around or measuring maximum temperature this is most often the cause of a damaged sensor. The inner cables of exhaust sensors are very fine and can be damaged if the cable is twisted or bent backward and forward too many times.

 See example of a twisted cable in exhaust sensor.

Exhaust Sensor incorrectly installed

Other examples of we have seen of causes for an exhaust temp gauge to read low readings are:-

1. Gauge has been installed in the blanking (enclosed) area on the exhaust - not the exhaust gas area

2. Poor earth on the gauge wiring

3. A cable has been pulled out of the plug on the back of the gauge. 

4. Both exhaust probe wires are frayed and rubbing together. THis is a common cause of gauge temps fluctuating all over the place.


Exhaust Gauge bouncing around after it rains, or you have washed the vehicle.


This is normal, when Exhaust sensor are saturated with water. You will get false readings until the sensor dries out.

All exhaust sensor (regardless of brand) are not water proof, to stop this occurring customers can insulate the sensor wiring with split tubing, like they should be doing anyway.