0-320 EGT fluctuating on #3

[moll780]

yesterday went for a flight to houston from austin and on the way back the EGT #3 fluctuated wildly, from -50 through 1800. the cht and egt's for the others were stable and fine.
I'm thinking there is an issue with the sensor.
tomorrow i'll pull the cowling, but any suggestions what to look for?

RV-9A, o-320 with 311 hrs since new. dynon d10. OAT time of first fluctuation was around 62F, other egt's between 1200 and 1300, LOP. tried running rich, lowering throttle, increasing airflow (pitching down) etc.. it would still ride up then down.

thanks

[glasserw]

Originally Posted by moll780

yesterday went for a flight to houston from austin and on the way back the EGT #3 fluctuated wildly, from -50 through 1800. the cht and egt's for the others were stable and fine.
I'm thinking there is an issue with the sensor.
tomorrow i'll pull the cowling, but any suggestions what to look for?

RV-9A, o-320 with 311 hrs since new. dynon d10. OAT time of first fluctuation was around 62F, other egt's between 1200 and 1300, LOP. tried running rich, lowering throttle, increasing airflow (pitching down) etc.. it would still ride up then down.

thanks

I think you will find that the EGT probe needs to be replaced. Remove from exhaust and you may find the tip significantly worn or wires bare. I have 400+ hours on my -4 and over the last year have now replaced all four. Suggest you pull the others to get an idea of how long the others may last.

[Jamie]

The problem is almost assuredly the probe. See this thread.

http://www.vansairforce.com/communit...ight=Dynon+egt

Oh yeah, my ksavionics probes referenced in the thread are still working great!

[turbo]

i dought you have a worn out probe in 300 hours. check your connections.

[Jamie]

Originally Posted by turbo

i dought you have a worn out probe in 300 hours. check your connections.

Ed, read the thread I linked to above. Lots of guys have burned through Dynon-supplied probes in less time, including me. Some less than 100 hrs. My new probes from ksavionics are still doing great. My anecdotal conclusion is that they are far superior to the probes I received with my Dynon EMS.

[moll780]

I took the cowling off this morning and found what I think is cylinder 3 (right rear) EGT probe was little loose. i tightened the hose clamp about 2 full turns just to check how loose.
i then removed the clamp and checked the probe and its still whole.
so back on it went.
I'll get a chance to check its function sometime tomorrow or this weekend.
I may go ahead and buy a replacement set anyway and swap them out at the next annual unless this resurfaces again.
thanks for all your input!

[RONSIM]

I started to replace them and then decided to check the wiring connections under the cowl --- sure enough, two of them did not have good crimps --- no more problems in over 100 hrs.