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EGT display on EFIS - 1 of 6 cylinders displays differently

PostPosted: Sun Dec 09, 2018 6:32 pm
by BillinDurham
In the beginning, all 6 cylinder’s EGT bar graph, as sensed by the EIS and displayed on an HX (and now on an HXr as well), looked and functioned normally.

At some point cylinder 6 displayed no bar graph value when relatively cold while the other 5 cylinders’ bars displayed nominal values. Once reaching the normal range of values, the 6 bar began displaying normally.

I probably caused this my inadvertently making a settings change in the EFIS or even perhaps the out of sight EIS. It’s as if the 6 bar is simply setup differently but I can’t make any sense of where such setup change can be made.

I’ve also replaced several EGT probes over the years, which could have had an effect but i have difficulty seeing how that might occur.

Any advice on where to look or how to troubleshoot appreciated!

Re: EGT display on EFIS - 1 of 6 cylinders displays differen

PostPosted: Wed Dec 12, 2018 7:34 am
by GRT_Jeff
There is no setting that can cause one of the EGT inputs to behave unlike the others. This has to be something going on in hardware. It could be a weak connection or failing probe. The EGT/CHT Basic Troubleshooting section in the EIS Troubleshooting Guide may help for checking the probes and wiring.

Re: EGT display on EFIS - 1 of 6 cylinders displays differen

PostPosted: Tue Dec 25, 2018 2:34 pm
by BillinDurham
I have yet to go through the troubleshooting guide. After reading it, I will probably end up swapping in a new probe which I suspect will fix it.

However, I’ve attached 2 photos:

1) The first shows a cruising situation with the EGT set to display changes relative to a point in time. Cylinder 6 ‘1F’ appears to work normally.

2) The second shows the same cruising situation with EGT set to display the actual temperature. Here one can see that
Cylinder 6 displays a temp ‘220F’ that is impossibly low.

Any comments welcomed.
2388F62C-76C2-42F8-B24C-0DF39F8BE280.jpeg
2388F62C-76C2-42F8-B24C-0DF39F8BE280.jpeg (778.65 KiB) Viewed 1329 times
4A42A300-A258-4875-A3DB-7DC18E622FEA.jpeg
4A42A300-A258-4875-A3DB-7DC18E622FEA.jpeg (842.04 KiB) Viewed 1329 times

Re: EGT display on EFIS - 1 of 6 cylinders displays differen

PostPosted: Wed Dec 26, 2018 5:42 am
by Bobturner
The normalize mode just shows how the CHT has changed since the mode was first selected. Evidently #6 was at 219, it’s now at 220, so it’s changed one degree. Most likely a new probe is needed; they live a hard life.