Erratic CHT Reading

[drferrell]

I'm stumped. I have a Dynon Skyview with the EMS module. A few weeks ago my #4 CHT started acting up. At times it reads minus degrees , other times it reads very low, jumps around or doesn't read at all (red X over the label). The EGT readings for #4 are normal. The other 3 cylinders read normal.
It usually starts working fine after a few minutes of flight.

So today I replaced with the CHT probe with a new Dynon probe and I still have the same issue with it. Any hints on what could be going on? I did not replace the female barrel fitting the probe bayonets to., I was wondering if that could causing a ground issue?

All advice appreciated! Thanks

 

[kurtfly]

Most likely a broken / intermittent wire. check any bayonet connections and also check the D 25 connector at the EMS module for a pushed in pin or socket.

kurt

 

[preid]

since you mention that it goes away when warm, and you have a new CHT probe, you’re in right direction by replacing the connectors on #4 EMS side.
But usually your symptoms are a loose connection, or maybe a broken wire, as already mentioned, so
start by swapping 4 with another known working probe( just because you have a new probe doesnt mean it works . If the (working) probe works fine, than plug the new 4 into the other CHT connector. If you have a bad wire it will show, bad probe, same, than take it from there. bad wire / replace connector. No use replacing the connectors on wire before confirming that’s the issue.
best of success troubleshooting.
let us know how it works out and what it was.

 

[drferrell]

Thanks for the advice. I replaced the female barrel the bayonet connects to and also cut out the spade connectors and soldered the wires together. Viola! Not sure which of those 2 actions solved the problem but it's working perfectly now. Yay! My guess is that one of the spade connectors had a poor connection. When in doubt ... solder it!