Lane A indicates high EGT before start - up

by Ross rynehart in 912iS Technical Questions 7 years ago

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Re: Lane A indicates high EGT before start - up

by Ross rynehart » 7 years ago

Ross rynehart

1 9 0

Hi Richard,

That's interesting information about the new sensor in the 915. I saw a 915 engine in one of the sti's on the Team Kitfox site - will be interesting to hear about the performance. And the flyin looked like fun. I will make an enquiry to the local Rotax dealer about those new sensors. They certainly sound like an improvement - I agree with you about the design improvement - I wonder if they are exchangable/compatable with the ones on the 912is?

On your point of carrying a spare - I also thought about that. I assume that the sensor is providing info to the computer to adjust fuel mixtures? Could be a problem in remote areas.

thanks for the infor.

r

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Re: Lane A indicates high EGT before start - up

by Bill Hertzel » 7 years ago

Bill Hertzel

13 1.95k 7.96k

Losing an EGT Probe is a Non-Event.
The EGT is informational only, it is Not used by the ECM to adjust Fuel mixture.

The Lane will display an alarm if the EGT goes out of range but will not take any action to adjust the mixture.
This is why the engine continued to operate normally when the EGT probe died.

If the ECM saw a cold exhaust due to a failed sensor and tried (incorrectly) to adjust the mixture in an attempt to correct the problem, that cylinder would have gone over-rich and started missing.
As it was, the ECM tried to isolate the bad injector on the apparently Cold cylinder and found that neither one resolved the problem.
The ECM concluded that it had no solution, and the Solid RED was displayed to get the pilot's attention so that he could take appropriate action.
In this case, the appropriate action was to continue to the destination and replace the probe when convenient.

The RED light made you look at the panel. Without it may have never noticed the Cold Exhaust.
You saw one EGT showing a cold exhaust, but the engine was still making full power.
The conflicting information should have formed the conclusion that the probe was lying.
I know it looked serious at the time, but it really was a non-event. Both ECMs were still operating.

If you saw the RED Lamp and the engine started missing, The Cold EGT reading would have informed you of the problem's location.
In either event, the ECM takes no action to adjust mixture other than toggling injectors.

Bill Hertzel
Rotax 912is
North Ridgeville, OH, USA
Clicking the "Thank You" is Always Appreciated by Everyone.

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Title	Category	Replies
Loose EGT probes	912 / 914 Technical Questions	3
High EGT	912 / 914 Technical Questions	12
Cylinder 1 EGT drop out	915iS Technical Questions	0
915is > 250 RPM drop on lane check	915iS Technical Questions	1
RPM issue, first start, new engine	912 / 914 Technical Questions	8

Lane A indicates high EGT before start - up

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