R

Rupester

Well Known Member
Took off today with everything looking fine ... All numbers in the green. Got to about 2500' climbing for 3500' when I got an engine alarm .... "EGT spread too wide". looked at the EGTs quickly and saw that all were 1100 to 1200 except #3 which showed 1470 and still climbing. Yikes ... Never had an EGT go wacky like that. I called for landing and soon after pulling the power back, all EGTs were around 1150. I landed with everything looking oK.... Taxied to the penalty box and did another runup .... Everything normal. Mag/plug check was fine. Took off again and had no problem whatsoever. Flew for 1.9 doing flight testing stuff. No issues. Anyone have an idea ? (BTW, 32.4 hr Hobbs when I took off the first time. )
 
Best guess would be a plug off line from a # of different reasons. Could have been nothing more than a fouled plug that cleared itself. Could be other ignition related.
Would have been good to do a mag check while the egt was spiked. Dont get nervous when an egt spikes. Take a moment to troubleshoot from a safe spot overhead.
 
Loose connection

if you see this behavior again and its spikes up closer to 2000 degrees, suspect a loose connection particularly at the crimp connection.
 
A mag check would have been a good idea. As mentioned above these can easily be identified by doing that under power, the one failing will show up with dropping egt while others rise, and a bit of rough running.

It is important to note that a faulty plug will fail under load in the engine yet pass the traditional bomb tester.

As a guess the bottom plug on that cylinder may have lead ball buildup.
 
Thanks much, gents ...

... I'll pull the plugs next week. This weekend is the HopsnProps gig in Oshkosh ... I'll be there until late Sunday. (FYI .. not taking 385TE, for lack of 40 hrs)
 
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