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  #1  
Old 06-05-2017, 07:59 PM
24Golf's Avatar
24Golf 24Golf is offline
 
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Location: Madison, MS
Posts: 139
Default EGT Fluctuation P-MAG or something else??

Please see link below:



My #4 EGT started fluctuating in climb and cruise on a recent flight. It has ALWAYS been smooth just like the other EGTs in the chart. I have checked the intake tubes, cleaned the injector, re-crimped the sensor wire and bore scoped the cylinder and still get this unusual fluctuation. Today I did an in flight mag check - see chart. Any ideas, It appears to fluctuate in climb and cruise, but smooths out during decent??

Thanks!

Engine: Lyc IO-320
Dual P-Mags / BR8ES Plugs 8 hours old
850 hours Total Time
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Vans # 91642
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  #2  
Old 06-05-2017, 08:38 PM
CamTom12 CamTom12 is offline
 
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Location: Huntsville, AL
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Quote:
Originally Posted by 24Golf View Post
Please see link below:



My #4 EGT started fluctuating in climb and cruise on a recent flight. It has ALWAYS been smooth just like the other EGTs in the chart. I have checked the intake tubes, cleaned the injector, re-crimped the sensor wire and bore scoped the cylinder and still get this unusual fluctuation. Today I did an in flight mag check - see chart. Any ideas, It appears to fluctuate in climb and cruise, but smooths out during decent??

Thanks!

Engine: Lyc IO-320
Dual P-Mags / BR8ES Plugs 8 hours old
850 hours Total Time
Have you pulled the sensor to inspect it? I've heard of some types literally wearing out over time.

How's your CHT for that cylinder? Normal? Have you checked your exhaust valves for wobble/tightness in a while?

Just guesses, but I fixed your picture link!
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  #3  
Old 06-05-2017, 09:21 PM
erich weaver's Avatar
erich weaver erich weaver is offline
 
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Location: santa barbara, CA
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Swap sensors with another cylinder and see if the problem follows the sensor then you either have identified the problem or ruled out the sensor.
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  #4  
Old 06-06-2017, 06:11 AM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 10,897
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This is unlikely to be P-mag related. The reason is the P-mags fire two plugs at the same time, in your case #2 and #4. Thus, if you problem was P-mag related, it would most likely show up on two cylinders.

However, it is possible you might have a bad sparkplug in #4 or a loose plug wire.

Based on the graph you posted, it got worse when running on just the right P-mag, so I would start there and trace down the plug and plug wire to the #4 cylinder.

Check your PM's.
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  #5  
Old 06-08-2017, 07:39 AM
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24Golf 24Golf is offline
 
Join Date: Sep 2007
Location: Madison, MS
Posts: 139
Smile Sensor Issue

Thanks for the input, looks like it was just a sensor issue. Yesterday we changed both plugs in #4 (cheap & easy since cowl was off), and swapped the EGT sensors #2 & #4. Apparently during the swap (#4 was hard to get out), we put the #4 probe "out of its misery" . When we cranked up, the #4 readings were swinging wildly while the #2 readings were normal. Ultimately the #4 reading went to a big red X, so I have a new probe coming.

Should have done this in the first place, but several folks (including myself) thought the sensor failure mode was "all or nothing" not a few degrees of variation.
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FLYING 10.15.2010
BLOG: http://2flyamerica.com/
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