EDM 700 CHT probe question

[BaldEagle]

I finally got one of those boxes from JPI and pulled the engine data for the last 6 months.  These are the most recent two flights: I need to replace the CHT probe on cylinder 2, yes?  Anything else I should check first?  Bad ground, cable?  Airplane needs to go into the shop soon anyway to address a couple of other minor squawks, but I thought I'd reach out here first, as I like an excuse to pull the cowling off and poke around.  I did notice in the logbooks that the previous owner had replaced a CHT probe recently and I think it was for the same cylinder (I need to double check), which is why I'm thinking possible grounding or other issue.

[carusoam]

Why replace without finding out why it is behaving the way it is?

It is certainly misbehaving.  Proactively swapping it out should work. Unless something is broken further upstream...

You will quickly learn if your #2 TC is actually mounted on your #2 cylinder.

Go for it.

CHT probes are not in the same environment like EGT and TITs are... they typically last a lifetime...

Of course, if this TC gets removed a lot for maintenance reasons, like a spark plug gasket type CHT TC does... expect to need to swap it out... with a better design, see piggy-back TC from JPI...

PP thoughts only not a mechanic...

Best regards,

-a-

[Steve W]

If the cylinder 2 and cylinder 4 wires are connected to the harness at roughly the same point, you(of course I mean an A&P) can easily swap the wiring under the cowling so 2 feeds #4 and 4 feeds #2 and make sure that the problem is with the probe and not the wiring harness between the connection and the instrument.

[larryb]

These sensors run both + and - all the way to the jpi. So a bad ground is not a consideration. What is a consideration is the connection of the sensor to the jpi harness. There is a star washer that is supposed to go between the terminals. This is specified in the jpi install manual which I would suggest reading. If the connection checks out then swapping the sensor, as already suggested, is a good way to isolate the issue.