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Date: Sun, 26 Aug 2012 10:53:43 -0400
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Subject: Re: [LML] Spiked CHT
From: Charles Brown <browncc1@verizon.net>
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Robert, I would guess intermittent partial injector clogging, here's =
why:

1.  I have never seen a thermocouple fail by 100 deg or so; in my =
experience they either work or they don't, with max scale readings =
either way depending on how they're wired.

2.  In 150 hours on my 550 I've had two partial injector clogs that have =
driven up the associated EGT (and CHT down) each time.  I've been quite =
thorough with fuel flushing and filter cleaning, and never get any =
sediment out of the tanks (so the fuel from my airport is clean), but =
somehow contaminants got through.  In each case, I could see the =
blockage and I extracted it by blowing air backwards through the =
injector.  My engine's normally aspirated, yours is turbo but that =
shouldn't make any diff.  Your problem responded to enrichening and =
leaning, which seems to indicate a mixture-related issue, not a =
thermocouple problem.

3.  In a Mooney 252 (TSIO 360) I had EGT jump on one cylinder, it turned =
out to be a stcking exhaust valve.  Mixture changes did not affect that, =
so I don't think that's your problem.

Charley Brown
Legacy #299  150 hr

On Aug 25, 2012, at 7:56 AM, Lancair wrote:

Last week I had been cruising LoP and during the power back for landing
Cyl #3 suddenly jumped 125F and sent the Chelton lady shouting into my
ear.  That would not be unusual if I had failed to either further lean
or go full rich but in this case I had leaned and the other 5 cylinders
were OK.  I leaned way back and really lost power and then went full
rich, and it finally settled down.  On the return flight I reduced power
and carefully kept leaning and had no problem.   Yesterday it was deja'
vu all over again.  Powered back on approach and only #3 went nutso
until I leaned even more.  On the return flight there was no recurrence.


Does this sound like a problem with the injector, with the thermocouple,
or ? ? ?

Robert Simon
ES-P N301ES
(TSIO550)