Unrealistic engine temperature indication during start-up

[sdreagan]

The EGT indication on startup climbs to over 300 degrees even before fuel is introduced on startup. To review, external power is applied, and external air is made available but not applied with the Ground Power On call. Then depressing the big start button opens a valve that allows external air into the engine causing rotation to begin (RPM). At 5% the throttle is Right-Clicked inboard to begin firing the igniters, then at 15% another right click moves the throttle to the idle position introducing fuel to the mix. So now all three start ingredients, necessary for combustion, are present. Combustion will now occur and the EGT will begin rising. It will increase steadily, and fairly quickly to over 400 degrees, to as much as 425 to 440 depending on many factors including OAT, and the condition of the engine being started. Then when engine RPM catches up, say to over 40 to 45 percent it begins pulling outside air into the engine, which cools the EGT preventing it from going above 455 degrees. Then, EGT falls finally settling at about 340 degrees, which is the steady state idle value. That's what should happen. What does happen is that as the igniters are started (First right click on the throttle, second step in the process and prior to fuel introduction) the EGT rises to 340 degrees and then does not react to combustion when fuel is introduced during step three of the start process. The link is to a short video.
https://1drv.ms/v/s!AlwQEzXCJXxZheNsb2AQ1OW-6VWpQw?e=QajZf2