Confirm an EGT issue?

[ChiefPilot]

I've been watching a funny EGT issue for the last couple of flights and am looking for either confirmation that I'm going down the right path.

Symptom is that EGT on #4 will go from ~1350ºF (which is within 30º of the other cylinders) up to 2000ºF over the span of a few seconds, stay there for a bit, then come back down. During this time, the engine sounds normal and other observable and logged engine parameters do not appear to fluctuate - CHT #4, for example, remains constant. The engine itself is a parallel valve IO-360 w/dual P-Mags and has run about 320hrs since new.

My first suspicion was a bad connection, as cleaning the connector seemed to alleviate the problem but then it recurred again after a few flights. The EGT probe itself looks ok (i.e. not burned away as some other pictures of Dynon probes have shown). Next step is to swap it with another cylinder.

My theory is that the probe itself is flaky, based on all other engine parameters being normal. Does that theory seem sound?

Thanks!
Brad

[Kahuna]

Originally Posted by ChiefPilot

Next step is to swap it with another cylinder.

Thanks!
Brad

As long as what you mean is that you will unplug it and move it. What your looking for is to see if its the probe or the wires. Unplug it, swap with another, will do that. Its probably what you meant, but swap cylinders, by moving it without unplugging it wont tell you anything in this case.

[Greg Arehart]

Yep, swap the connector wires and if the problem (apparently) goes to another cylinder, it is probably the thermocouple connection in the probe gone bad.

Greg

[ChiefPilot]

Yes, swapping connectors is what I was referring to. I should've been more specific.

Thanks!

[LettersFromFlyoverCountry]

I had the same problem with an EGT probe. I'd bet dollars to donuts that you'll find this is what your problem is.

[eddieseve]

Re crimp your connectors, I had an EGT where one of the connectors had come loose causing strange readings.

Cheers

[PCHunt]

Electronics International has come out with a new connector for EGT, CHT, etc. Rather than crimping terminals on, and then connecting the terminals, you simply put the two wires in and tighten the set screw. Eliminates several joints, and easy to install with no special tools.

See: http://buy-ei.com/portfolio/olc-1/