bad CHT probe

I replaced my Cylinder #1 CHT probe in 6/2019. The new probe has now also gone bad. Seems a little too coincidental.

Looking back through data, this new probe was perfectly fine until about this past March. I can see from that point on it's been getting progressively "jumpier" on each flight. It's especially bad when power is high. EGTs are all stable and well behaved.

Anybody have any idea what might be causing my #1 CHT probes to go bad?

I have had similar issues, as well as the original builder of my RV7. #1 never works. I thought, and still do it is a poor connection/Wire crimp. Just need to go to mech and borrow a D-Sub pin crimper and re wire it sometime soon.

Jon

RV8JD said:

Dynon probes by any chance?

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Yes they are ???

Try cutting off the connectors and replacing them with standard Fast-tabs. Add a piece of #20 wire in the connector with the probe wire - makes for a better crimp connection.

Carl

RV8JD said:

Dynon probes, both CHT and EGT, have a bad rep. I've had a few of both fail. Some say it's the connectors and/or the crimps, so try Carl Froehlich's suggestion.

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Thanks. Will do.

RV8JD said:

I saw your other thread regarding your question on EGT #1, and wondered if you fixed your CHT #1 issue?

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I replaced the CHT probe. Problem was even worse. Then I rerouted the probe wires away from the plug. So far so good. Compared to the other CHT probes #1 wires were running very close to where the ignition wire enters the plug. Perhaps #1 is electrically noisier due to the other issue. ??

The EGT issue has been exactly the same since first flight. I think the two problems are Probably unrelated or only indirectly related. But who knows.

Thanks for noticing, by the way. This really is a great community of builders all looking out for each other.