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  #1  
Old 12-30-2014, 11:40 AM
spatsch spatsch is offline
 
Join Date: Nov 2014
Location: Denison, TX
Posts: 308
Default High CHT event on one cylinder

I uploaded my Dynon logs for the last 12 hours of flight time to Savvy today and found an unusual CHT graph I am looking for feedback on. First some background. This is a new IO-360 which has about 50 hours on it now. Usually CHT of all cylinders track each other well and stay below 400F.

Now to the graph in question. The graph below shows two short flights (I plotted the DALT so you can see when I was flying). Looking at CHT of cyl. #2 it starts departing from the other cylinders during the first flight and then really departs when I was taxing to take of again before the second flight. I didn't notice that during the flight (my CHT alarm WAS set to 500....) . FYI you can ignore the short spikes in the CHT those are cause by my radio transmitting.



Now after the event everything went back to normal and I have flown 10 hours since without any anomaly. Never saw that issue before or since. E.g. the next flight:



Any idea what that was?

Oliver
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  #2  
Old 12-30-2014, 12:15 PM
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dynonsupport dynonsupport is offline
 
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Notice how noisy it gets when it's anomalous? That makes it look like a bad probe or connection. Real temperatures can't move that fast. I'd look carefully at your crimps and pins for that channel.

Also, you can send us your EMS module if you want it updated to get rid of the EGT/CHT spikes with the radio transmission.
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  #3  
Old 12-30-2014, 12:20 PM
RVDan RVDan is offline
 
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Possible probe going bad?
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  #4  
Old 12-30-2014, 12:28 PM
spatsch spatsch is offline
 
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Quote:
Originally Posted by dynonsupport View Post
Notice how noisy it gets when it's anomalous? That makes it look like a bad probe or connection. Real temperatures can't move that fast. I'd look carefully at your crimps and pins for that channel.

Also, you can send us your EMS module if you want it updated to get rid of the EGT/CHT spikes with the radio transmission.
Good point. Will check the wiring. I did use a harness so I really only had to crimp two connectors for that sensor but I guess there is nothing saying that the harness I bought was perfect to begin with so will check the whole thing... .

Will contact you about updating the EMS model. Didn't know there was a fix available.
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  #5  
Old 12-30-2014, 04:45 PM
N427EF N427EF is offline
 
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Can't be much help with your EGT anomaly.
Couldn't help but notice your CHT alarm was set at 500F
Not sure if the word "was" means you have changed it since but if you haven't
Do so and set it somewhere between 400 and 450 whatever suits your temperature range.
Knowing that you hit 500F is of little use after the fact.
Best to keep your temps somewhere below 380F so my alarm is set at 400F.
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  #6  
Old 12-30-2014, 06:23 PM
spatsch spatsch is offline
 
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Quote:
Originally Posted by N427EF View Post
Not sure if the word "was" means you have changed it since but if you haven't
Do so and set it somewhere between 400 and 450 whatever suits your temperature range.
Yes changed it already as my CHTs stay below 400 in normal operations I set it to 400.

Oliver
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  #7  
Old 12-31-2014, 09:01 AM
barryrv10 barryrv10 is online now
 
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To be on the safe side, borescope that cylinder. Blue Skys
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  #8  
Old 12-31-2014, 09:20 AM
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ColoRv ColoRv is offline
 
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I'm in the camp of bad sensor or connection. Temps can't do what that display is showing...means display error. Engine sounded and felt fine...right?
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  #9  
Old 12-31-2014, 09:25 AM
David Paule David Paule is offline
 
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It might be worth pulling the cowl and taking a look to make sure that nothing's physically loose.

Dave
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  #10  
Old 12-31-2014, 11:49 AM
spatsch spatsch is offline
 
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Quote:
Originally Posted by ColoRv View Post
Engine sounded and felt fine...right?
Yes. It not only sounded/felt fine it also performed fine. Didn't show it on the plot I posted but manifold pressure, rpm, fuel flow, climb rate etc.. . were normal during the flight.

Haven't head time yet to carefully trace the sensor cable as was suggested but will do so next. I did have a quick look under the cowl but didn't see anything obviously wrong.

After thinking about it for a while I do agree that the temps can't change that quickly in an engine. So it must be the connectors, cable, probe or EMS module. One odd thing is that I have flown 10 hours since. I would have expected a loose connector or broken probe/EMS to act up again in that time period.
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