Fluctuating EGT AND CHT readings

Rocky_W

New Member
Joined
Oct 6, 2019
Messages
8
Hello

For years my EGT and CHT readings have been fine. Yes, I had to replace a burned-out EGT probe a couple of years ago, but that is it.

Recently I started to see fluctuating CHT readings and fluctuating EGT readings followed swiftly. This is on one cylinder only. With fluctuating I mean that the values almost constantly move up and down. The reading on the other cylinders remain stable. The sensitively of this fluctuation seems to depend on MAP / RPM settings.

I couldn't find a similar thread on here. Mostly it is about an issue with one of the two parameters but not both at the same time.

What could the cause be? Because it fluctuates so quickly I suspect it is an electrical issue. But is it simply a coincidence that the CHT and EGT seem to be impacted at the same time?

I would appreciate some direction before I start the fault finding process.

Thanks

Roger

IMG_5230.jpg
 

preid

Member
Joined
Jan 22, 2010
Messages
754
Location
SoCal
Are you saying the cht has a quick change in temperature? If so it’s the probe. CHT is a slow moving probe.
pull the files and load to savvy than post, it will help in seeing the actual changes.
what Happens when you do a Mag check? Does that same cylinder show a different change than the rest? For example, left OR RIGHT Mag CHECK shows a decrease in EGT or a slight change compared to others. Do the Mag check at the leanest possible position when doing it, all Mags should go up really quickly.
 

HFMan

Member
Joined
Aug 28, 2019
Messages
81
When mine did that, it was a bad pin connection on the large connector plugged into the EMS module. The wire had actually pulled out of the pin (or rather nearly pulled out). I would agree it is very odd that this happened on two of your sensor inputs.
 

kellym

I love flying!
Joined
Sep 29, 2013
Messages
273
Usually the connectors. I use OLC-1 or OLC-2 connectors and have found zero problems on every installation I have used them on.
Absolutely correct. Buy them direct from Electronics International in quantities of 5 or more and get the allen wrench and shipping free for the outrageous price of $1 per connector. I have my fuel flow, all EGT, all CHT and now my GPS250 connected with them. Rock solid, low resistance connections, and reusable anytime you need to change a connection. I don't know a better way to connect any wires #18 and smaller.
 
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