flyboy0681 Posted October 14, 2018 Report Share Posted October 14, 2018 I noticed this on the way home from a $300 hamburger yesterday. The other three cylinders were firing just fine, and the temp on this one was stable the entire time. IMG_3604.MOV Quote Link to comment Share on other sites More sharing options...
Piloto Posted October 14, 2018 Report Share Posted October 14, 2018 It is a connector problem on the probe lead. try cleaning the contacts. José Quote Link to comment Share on other sites More sharing options...
Guest Posted October 14, 2018 Report Share Posted October 14, 2018 Likely a bad connection. JPI says to install the lock washer between the ring terminals, something missed by many installers. Clarence Quote Link to comment Share on other sites More sharing options...
m20kmooney Posted October 14, 2018 Report Share Posted October 14, 2018 (edited) It certainly is a probelem!! Edited October 14, 2018 by m20kmooney Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted October 14, 2018 Report Share Posted October 14, 2018 Swap the probe connection between 2 and 4 and see if the problem moves. If the problem moves you know it is the probe. The exercise itself may fix it. Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 14, 2018 Report Share Posted October 14, 2018 50° F EGT oscillations that quickly...? unlikely without a valve doing something funny. so swap the probe wires first... Then look up sawtooth EGT patterns at Saavy... post your EGT graph here and load it into Saavy for pro advice... if the pattern is regular and sawtoothed, not randomly all over the place... expect sending a camera down the spark plug hole to gaze at the exhaust valve... Gazing will indicate a pizza looking design or something less appetizing... Check with paul... if I could remember his screen name @p.... PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Marauder Posted October 14, 2018 Report Share Posted October 14, 2018 Looks exactly like my loose probe issue. Check the connector between the probe and the harness. Quote Link to comment Share on other sites More sharing options...
flyboy0681 Posted October 15, 2018 Author Report Share Posted October 15, 2018 Thanks all for the quick reply. I'll check out the connection next weekend and report back. Quote Link to comment Share on other sites More sharing options...
THill182 Posted October 15, 2018 Report Share Posted October 15, 2018 Happened to me before, and was a sensor/connector problem. One question I have: If one of the cylinders really goes "cold", wouldn't your engine run rough? In my case, everything else worked and felt exactly the same, performance was the same, and I still got CHT readings (but no EGT). If one cylinder really goes, I would expect a great deal of imbalance, wouldn't I? Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 15, 2018 Report Share Posted October 15, 2018 If a 50° EGT oscillation was really happening... it could be as simple as a spark plug being failed. Then coming back on line... and then failing again... Each time the plug would fail... the corresponding EGT would rise. Similar to doing a run-up, but only for one cylinder... Interesting point... check the spark plugs in that cylinder for any signs of the word champion being printed on it anywhere or in the log books... The ever increasing resistance in Champion spark plugs doesn’t usually oscillate... As far as loose wires goes... a loose spark plug wire would be kind of unique. But could cause a similar dead plug situation... Now... could you, would you, feel it... probably... you would sense a strange minor change in the engine output and you would look at the jpi for confirmation... PP thoughts only, not a mechanic... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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