EGT PROBE PROBLEMS

[ZK-LCM]

During a test flight yday my No 3 EGT temp went off the scale (1111 deg C) & stayed there even when the engine cooled down after shutdown.
My RV6 is powered by a zero-hour O-320-D1A & features a D100 EFIS, & a D120 EMS. It has done approx 14 hrs test flying so far & the engine has been running very well, smoothly with stable very T's & P's.
Upon closer inspection No 3 probe was found to have a relatively thick carbon buildup. Removing the carbon the temp dropped to ambient, but on reassembly reverted to >1100 deg C.
Has anybody had such experience, and/or can suggest what typical affects would be of carbon build up on the thermocouples.

Thank You
Graham
New Zealand

 

[MikeD]

Could be a bad probe, a bad connection or a problem in the EMS.

Check the spade connection crimps. If still reading incorrectly, swap the spade connectors from #1 EGT with #3 EGT. If #1 is reading incorrectly then it’s a bad probe. If #3 is reading incorrectly then the problem is either in the harness or the EMS.

FWIW, my EGT probes lasted 10 years before I had to replace #4. The replacement lasted less than a year before it failed.