Peter R. wrote:

Ray Andraka wrote:


Is your JPI set up for the correct probe type?


Could you expand on this? I do not know the answer and if this might be
the case, I would like to be able to approach my mechanic with an educated
question.



There are two types of thermocouples used for EGTs. K type and J type.
Each has a different coefficient for output voltage vs temperature. If
you have JPI probes, then that should not be a problem. If you used
other probes, they might not be the correct type, which would give
readings that are scaled.

Another possibility is if the probe wires were extended with wire other
than thermocouple wire, the junction between the thermocouple wire and
the extension wire will add an additional thermocouple to the loop,
introducing an offset voltage at the instrument. The offset voltage
will translate to an offset temperature indication that is proportional
to the temperature at the junction.