#3 Cylinder loss of temp data on takeoff?

Strange issue last weekend...

The previous weekend I flew from Portland, Or to Phoenix, Nv with no issues - except that pesky occasional fuel pressure drop that so many experience.

During the week, I upgraded Dyon EFIS and EMS from 3.0 to 5.6 Software.

During flight from Vancouver, Wa to Friday Harbor - both takeoffs saw my #3 Cylinder lose all temperature data CHT/EGT) but then regain temperature after a few hundred feet?? Also of note, not once did I have a fuel pressure drop in 2.5 hours of flight. I have ordered a Kavlico fuel pressure sensor already - but hasn't arrived. But strange I didn't see the issue over 2.5 hours.

But what worries me is the CHT/EGT drop to zero on take off. Engine seemed to run fine with no change in RPM/etc..

This week I will remove cowl for oil change anyway - so will check temp probes/etc..

pjoshyjosh said:

But what worries me is the CHT/EGT drop to zero on take off. Engine seemed to run fine with no change in RPM/etc..

This week I will remove cowl for oil change anyway - so will check temp probes/etc..

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Instrumentation error. Sounds like it's in the electronics rather than the probes and wires, if you lost both at the same time.

RV7A Flyer said:

Instrumentation error. Sounds like it's in the electronics rather than the probes and wires, if you lost both at the same time.

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That's what my original thought was - and strange it happened after a SW upgrade. But still don't want to look past a real issue without further investigation.

I had that once and found that my EGT connection at the engine side was loose. I disconnected, applied more electronic lube, tighten the female side of the blade connector slightly and it fixed it.

pjoshyjosh said:

That's what my original thought was - and strange it happened after a SW upgrade. But still don't want to look past a real issue without further investigation.

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Particularly with CHT, if the drop was sudden or instantaneous, think about it...the physics involved in heat transfer would indicate that it's a false reading, as there's no way to dissipate that much heat that quickly.

When I see rapid changes in temperature readings of any kind (and particularly when they are rapidly fluctuating), I'm pretty sure they're not real just because of the physical properties of the thing being measured.